Urban Traffic: A Function of Land Use 9780231899093

Table of contents :
Foreword
Preface
Contents
Figures
Tables
I. Orientation: Land Use and Traffic Problems in City Planning
II. Relating Land Use to Traffic
III. The Structure of Movement: Spatial and Temporal Organization
IV. Components of Movement Structures: Individual Movements of People
V. Systems of the Movement of Persons
VI. Systems of Movement of Goods and Materials
VII. The Influence of Movement on Land Use Patterns
VIII. Relating Movement of Persons and Goods to Land Use: Selected Explorations
IX. Toward Improved Methods of Traffic Analysis
Appendix A. Methods and Procedures of the Field Investigation
Appendix B. Classification of Items Pertinent to the Study of Movement
Appendix C. Channels of Marketing
Glossary
Index

Citation preview

URBAN

TRAFFIC

A Function of Land Use

Publications

of the Institute

Urban Land

Use and Housing

Columbia

University

for Studies

URBAN

TRAFFIC

A Function of Land Use

by and

COLUMBIA

UNIVERSITY

R O B E R T B. MITCHELL CHESTER

PRESS,

NEW

BAPKIN

YORK

1Q54

COPYRIGHT

Library

1 9 5 4 COLUMBIA UNIVERSITY TRESS, NEW

of Congress Catalog Card Number:

54-6483

PUBLISHED IN GREAT BRITAIN, C A N A D A , INDIA, AND B Y GEOFFREY CUMBERLEGE, OXFORD UNIVERSITY

YORK

PAKISTAN

PRESS

LONDON, TORONTO, B O M B A Y , AND K A R A C H I

MANUFACTURED IN THE UNITED STATES OF A M E R I C A

FOREWORD

of research, the Institute for Urban Land Use and Housing Studies has focused on two broad aspects of city life. The first field of studies is concerned with the behavior of real estate markets (two volumes have already been published and two more will be published soon). The second includes studies in the dynamics of urban land use: the manner in which people coming together in cities utilize land, the activities that proceed on the land, the structures that are erected to accommodate these activities, and the spatial arrangements of these activities and structures along with the streets and open spaces. But since cities rarely remain static, an understanding of the ways in which they change and the causes of these changes becomes vital if urban man is to shape his environment intelligently. I N FORMULATING ITS PROGRAM

Changes in the city proceed at an irregular rate. Particularly during periods of rapid growth, the structures created in the past and the needs of the present conflict. Perhaps one of the most dramatic, undoubtedly one of the most discussed, and surely one of the most frustrating, of these conflicts has manifested itself in the problems of moving persons and goods, and of the vehicles that transport them through the city with safety, dispatch, and efficiency. Although rapid and sometimes astonishing advances have been made by automotive, highway, and other transport engineers, the subject of city structure and growth has received insufficient attention from the social scientist and engineer. Time, technology, and changing patterns of human activities have created problems resulting in traffic congestion. Despite valiant efforts of persons responsible for the management of traffic in our cities, areas of congestion develop faster than they can be removed. In addressing themselves to this problem, the authors of this study have sought to penetrate the façade of traffic, with its vehicles moving or waiting to move. Traffic has been analyzed in terms of its underlying causes—the necessity for people to move, and goods

vi

FOREWORD

to be transported, from one place to another. Some of these movements are regular and predictable, others are sporadic and only predictable in the mass. But all movements can be viewed as falling within certain large systems, which in turn are manifestations of organized systems of urban activities. These activities are land based. Each of the various types of establishments constituting bases of activities has its own particular relationship to the movement of persons and goods in all its aspects. It is to explore these relationships, the various methods of analyzing them, and techniques of collecting information about them that this study was undertaken. T h e preface to this volume contains a brief history of the research project and the authors' acknowledgments. T h e officers of the Institute would like to take this opportunity to add their thanks to the many individuals and agencies that gave so generously of their assistance and advice, particularly to the officials and staff members of the United States Bureau of Public Roads, who participated in the original research project which preceded the preparation of this volume. In addition to this report, the Institute has presently in progress two other studies on the dynamics of urban land use. A study of residential mobility—an important aspect of the urban process— undertaken in conjunction with the Bureau of Applied Social Research is now in manuscript, and publication is expected shortly. T h e other study describes the structure of central business districts of cities and how they change. In this project new concepts and methods have been proposed and utilized to study i) the functions of the central district; 2) the ways in which changing function influences the general location of business enterprises, government agencies, and other types of establishments; and 3) the nature of the connections between establishments that explain their locational relationship to each other. Among the principles that have guided us in formulating the research program of the Institute, several have been of primary importance. First, it was felt that the Institute should not be concerned with projects of ephemeral interest or with the replication of work already undertaken. Rather it was felt that the Institute should devote itself to "basic research"—studies which seek to dis-

FOREWORD

VÜ

cover the underlying principles and relationships, and the modifying influences which govern urban land use and improvements. It has frequently been necessary to re-examine or reformulate existing concepts and to enunciate new ones, in an attempt to evolve an intellectual structure within which fruitful empirical research could be undertaken. Second, it was felt that problems in the real world could not be adequately studied from the point of view of any single discipline. Instead, it was necessary to call upon the resources of all relevant disciplines in seeking approaches to the problems to which the Institute has addressed itself. A glance at the membership of the Advisory Board and an examination of any of the studies prepared by the staff members reveals the variety of fields that contribute to the work of the Institute. In this study, for example, materials, concepts, and methods have been drawn from the fields of traffic engineering, economics, sociology, psychology, social psychology, marketing, and several others. Third, we have maintained that not only must research utilize and contribute to the body of existing knowledge, it must also provide a basis for future work. This means that a fruitful study, be it empirical or theoretical, asks as many questions as it answers, and points the way to new fields of study. Thus, while each study may be an entity in itself, it also constitutes a link with the past and a guide to the future. Another implication should be noted. T h e additive nature of a research study is reflected in ramifications that transcend its immediate purpose and that consequently can be utilized to implement research in other aspects of the field. In the work of the Institute, for example, data on land use from the central district study have been used in the study of the movement of persons and goods. Housing Market Analysis drew upon data from the residential-mobility study, information on home-to-work trips from the movement study, methods of measuring real estate transfers devised in Housing Market Behavior in a Declining Area, and techniques (in adapted form) from the central districts study. In this study of the movement of persons and goods the authors have been guided throughout by the principles delineated above. In a direct sense, cities are confronted with the necessity for solv-

viii

FOREWORD

ing traffic congestion and attempting, through more refined methods of prediction, to prevent it in the future. In a more profound sense, traffic arteries and the means of physical communication can provide a powerful instrument through which the growth or renewal of the city can be directed, and a more pleasant and efficient arrangement of land uses secured. It is our hope that this study constitutes a step toward this long-range objective, through transmitting an insight into the choreography of city life. ERNEST

M.

CHAIRMAN

FISHER OF THE ADMINISTRATIVE

BOARD AND DIRECTOR

New York, July, 1953

PREFACE

V O L U M E represents the further development of an unpublished report by the same authors under the title, "Systems and Structures of Urban Traffic," which was prepared in the Institute for Urban Land Use and Housing Studies in 1950 as the result of a cooperative research project of the Institute and the Bureau of Public Roads of the United States Department of Commerce. T h e project sought to enlarge some early studies which had been undertaken by the staff of the Bureau of Public Roads as a part of its regular research program and which dealt with the "traffic generating" characteristics of various land uses. These studies exemplified the Bureau's growing concern with the problems of highway location, design, and use in urban areas. From the beginning, this investigation was conceived as an exploratory or experimental phase of a larger research program, the purposes of which were: "(1) T o measure the movement of persons and the movement of goods associated with various characteristics of selected land uses and combinations and patterns of land use . . . ; (2) to measure vehicular and pedestrian street traffic, parking or unloading of vehicles and use of public transportation related to the above movement of persons and goods; and (3) to develop and test hypotheses, methods, and techniques of study which may be useful in subsequent similar studies in other cities; to test the adequacy of and possible modifications to standard internal and external surveys of the origin and destination of traffic for this purpose." Within these general purposes of a research program, the specific objectives of the exploratory phase on which this is a report, were: (1) to develop and test a conceptual basis for the project; (2) to test the feasibility of finding answers to various questions which may be asked; (3) to develop and test techniques and procedures for securing and analyzing data; and (4) to develop statistical tabulations and maps which will be needed in the precise formulation

THIS

x

PREFACE

of further research on the subject. In the course of the study numerous experimental questionnaire forms were used. A set of these is available for reference in the office of the Institute for Urban Land Use and Housing Studies. Philadelphia was chosen as the location of the research for several reasons. In the first place, a metropolitan survey of the origin and destination of traffic was nearing completion in that area under a joint agreement among the Pennsylvania Department of Highways, the United States Bureau of Public Roads, and the City of Philadelphia. In the second place, the Institute had a close working relationship with the Philadelphia City Planning Commission which was much interested in the proposed study and offered its cooperation, as did the Chief of the Bureau of Traffic Engineering in Philadelphia, and the Pennsylvania Department of Highways. Finally, the Philadelphia City Planning Commission had under way a major analytical study of the central district of the city in which the personnel of the Institute were acting in an advisory capacity. It was believed that the two studies would complement each other, which proved to be true. T h e description of movement within a city, with all its complexity, is relatively simple compared with its explanation, for its sources and consequences ramify throughout the fabric of human action in the urban setting. Explaining movement is necessary if we are to progress from perception of the current phenomenon to a reasonably sound projection of its future nature, influenced as it will be by city growth and development, and other factors. Such projection, with a sounder basis than we have enjoyed before, is essential to an improved quality of highway and city planning. Those who have conducted this study started with a limited perception of the range of inquiry into which the simple early questions have led. They emerge with the conclusion that a major field of urban studies is opened up when one begins to question the sources and influences shaping the movement of people and goods in cities. Change in land use is the reflection, sometimes delayed, of more fundamental changes in what people do on the land, in the manner of their doing it, and in the means and processes they employ. T h e problem of movement of people or of goods between or

PREFACE

Xi

among land uses is an aspect of the basic problem o£ systems of action within time and space. Discovery of the functions of persons and goods movement in these systems of action, the kinds of things people do, is the key to understanding why or when movement will change. The stroller on the city streets can observe what seems to be an indistinguishable maze of movement all about him. If he goes to a planning office and consults the reports of traffic surveys, he can see this movement measured and its general appearance described in ways that give it some form. But if he asks why, he still cannot discern within that structure any systems which relate cause and effect, which will enable him to understand its sources and determinants. He feels the need to assemble groups of individual kinds of movement which he can examine in relation to what inspired them, and toward what ends they were made. The development of a way of looking at movement, and the end of understanding how and when it may change, is the subject of the first part of this report and a major objective of this study. We often smile now when we see maps drawn by early explorers in the new world. The present study and report may be considered an early map of a new area for urban research. Those who have conducted the study and drawn the map as they have perceived that area earnestly hope that within a few years its territory will have been explored by many others and that this first rough diagram will soon become outdated by the results of other work. In accordance with the cooperative agreement between the Bureau of Public Roads and Columbia University, responsibility for much of the work on the study, which is the basis of this volume, was assumed by the university acting through the Institute for Urban Land Use and Housing Studies. Both parties agreed to contribute both personnel and funds, and a close working relationship was maintained throughout. Because of their previous experience in related inquiries, and because they were engaged in the analysis of the Philadelphia central district for the Philadelphia City Planning Commission, the firm of Alderson and Sessions was engaged by the Institute to assist in project formulation and to undertake field work under Institute supervision.

PREFACE

Xll

T h e authors take this opportunity to acknowledge the important contributions made to the study by Messrs. W r o e Alderson and Robert E. Sessions, and to a number of their staff members during the study, particularly Dr. Ernest Jurkat, Dr. Charles Goodman, Mr. Albert Eisenstat, and Mr. Theodore Nowak. A m o n g many others whose assistance added greatly to the study, particular acknowledgment should be given Dr. Reavis C o x of the University of Pennsylvania; Mr. Edmund N. Bacon, Executive Director, Mr. Paul Croley, Assistant Director, Dr. Hans Blumenfeld, and Dr. Dorothy Muncy, of the Philadelphia City Planning Commission; Mr. Robert A . Mitchell, Chief of the Bureau of Traffic Engineering of Philadelphia; Mr. H. G. Van Riper and staff members of the Pennsylvania Department of Highways; Mr. Victor H. Pelz of the Traffic A u d i t Bureau; and Dr. Robert K. Merton and Dr. Kingsley Davis of the Bureau of Applied Social Research at Columbia University. T h e authors thank especially all those who have kindly allowed their work, both published and unpublished, to be drawn upon for this report. Particular mention is due the members of the staff of the Bureau of Public Roads, particularly Mr. H. S. Fairbank. Because of his vision the study was undertaken and under his general supervision the Bureau's part in it was conducted. Mr. E. H. Holmes, Mr. J. T . Lynch, and Dr. J. T . Stegmaier of the Bureau participated directly throughout. O n the part of the Institute for Urban Land Use and Housing Studies, the work was aided by various members of the Institute staff, especially Mr. John Rannells, who participated in the preparation of the original report and of this volume, and who designed the figures and graphs, and supervised their preparation; and Dr. L e o Grebler, who discussed and reviewed the study as it proceeded. T h e authors wish to offer special thanks to Dr. Ernest M. Fisher, Director of the Institute and friend, for his wise counsel, assistance, and unfailing patience. ROBERT B. CHESTER

New York, July, 1953

MITCHELL

RAPKIN

CONTENTS

I. O R I E N T A T I O N : LAND USE AND T R A F F I C PROBLEMS IN CITY PLANNING The Guidance of Change in Land Use and Traffic Dealing with Urban Traffic at Three Levels Tools of Traffic Analysis Summary and Conclusions II. R E L A T I N G LAND USE T O T R A F F I C The Changing Nature of Land Use The Change in Urban Patterns The Locational Requirements of Establishments The Nature of Traffic Components in the Analysis of Traffic Summary

3 3 6 7 11 13 13 14 16 16 17 19

III. T H E S T R U C T U R E OF MOVEMENT: SPATIAL AND T E M P O R A L ORGANIZATION Forms of Mass Movement Spatial Characteristics Temporal Characteristics Summary

20 21 23 31 35

IV. COMPONENTS OF MOVEMENT STRUCTURES: INDIVIDUAL MOVEMENTS OF PEOPLE Establishments and Their Members Trips: Their Varieties and Characteristics Determinateness of Goals Roles in Which People Travel Summary

37 38 39 53 56 58

V. SYSTEMS OF T H E MOVEMENT OF PERSONS Systems Based upon Processes of Action Systems Based upon Kind of Trip Systems Related to Kind of Establishment or Area Systems Related to Areas of Assembly Summary

60 61 62 69 83 87

xiv

CONTENTS

VI. SYSTEMS OF M O V E M E N T OF GOODS AND MATERIALS Systems Based on Kind of Establishment Systems Based on Processes of Action Systems Based on Kind of Commodity Summary VII. T H E I N F L U E N C E OF M O V E M E N T ON L A N D USE PATTERNS The Locational Role of Movement The Friction of Space Linkage and Proximity An Illustration of Land Use Pattern Dynamic Relationships Changing Movement Requirements The Relocation of Firms or Households Changes in the Activities of Establishments at a Given Location Differential Growth Rates and Changes in Aggregate Activities Changes in the Available Supply of Space Changes in the Street System and Other Movement Channels Summary

88 90 93 100 102

104 106 108 110 115 118 119 121 122 122 127 129 132

VIII. R E L A T I N G M O V E M E N T OF PERSONS AND GOODS T O L A N D USE: S E L E C T E D E X P L O R A T I O N S 134 Traffic Analysis Methods 135 Journey-to-Work and Daytime-Population Studies 137 Studies of Persons-Movement 139 Some Selected Measures and Relationships 144 Assembly-Area Profiles 156 Relationship Between Truck Trips and Land Use 169 Summary 176 I X . T O W A R D IMPROVED METHODS OF T R A F F I C ANALYSIS Operations Research in Traffic An Analytical Model for Prediction Required Empirical and Methodological Research

178 179 181 182

CONTENTS

XV

APPENDICES A.

185 186 186

METHODS AND PROCEDURES OF THE FIELD INVESTIGATION

Preliminary Qualifying Interview Qualifying Interviews: the Questionnaire Experience with the Qualifying Interviews Differences among Establishments Case Studies Conclusion B.

CLASSIFICATION

C.

CHANNELS OF

OF

ITEMS

MOVEMENT MARKETING

PERTINENT

TO

191 195 197 200 THE

STUDY

OF

201 211

GLOSSARY

2!5

INDEX

221

FIGURES

1. Residence of Persons Making Trips to Subzone 00062

25

2. Origins of Truck Trips with Destination in the Port Richmond Industrial Area, Philadelphia, Pa.

26

3. Associated Destinations in an Assembly Area: Other Stops Made by Callers at a Department Store

27

4. Associated Destinations in an Assembly Area: Other Stops Made by Callers at a Retail Specialty Store

27

5. Associated Destinations in an Assembly Area: Other Stops Made by Callers at a Theater

28

6. Associated Destinations in an Assembly Area: Other Stops Made by Callers at a Small Service Establishment

28

7. District of Columbia Traffic Flow, Peak Hour, September, 1947

3°

8. T r i p Desire Chart, Sacramento, California

32

9. A n Aspect of Structure of Persons-Movement Based on T i m e and Purpose to and from Subzone 00062

33

10. An Aspect of Structure of Persons-Movement Based on T i m e and Mode of Travel to and from Subzone 00062

34

11. Destination Areas: Home-based Round T r i p

47

12. Destination Areas: Home-to-Work T r i p

47

13. Arrival Points and Bases in Central District for Callers at a Department Store

48

14. Assembly-Area Profiles: Retail Specialty Store

157

15. Assembly-Area Profile: Case I

159

16. Assembly-Area Profile: Case II

159

17. Assembly-Area Profile: Case III

160

18. Assembly-Area Profile: Case IV

161

19. Distance-Density Profile

163

FIGURES

XVII

20. Floorspace-Density Profile

165

21. Floorspace-Distance Profile

166

22. Zones and Groups of Zones Corresponding with P.C.P.C. Blocks 172 23. Floorspace and Number of Truck Trips

172

24. Floorspace and Number of Truck Stops

173

25. Percent of Floorspace in Each of Six Land Uses and Average Number of Truck Trips per 1,000 Square Feet of Floorspace 176 26. Simplified Diagram of Planning Analysis Process (to illustrate Problem 1) 180

TABLES

j. Mode of Transportation Used and Average Time Required to Arrive at Destination from Last Base, by Callers at a Department Store and a Theater

42

2. Distribution of Trips by Type, Average Number of Stops in Central District, and Percent of Trips Having the Subject Establishment as the Sole Destination, by Callers at Each of Four Establishments

49

3. Type of Establishment Visited by Callers at a Department Store and a Theater; Number and Percent of Total Stops; Percent of Total Stops Made at Other than the Subject Establishment

50

4. Average of Maximum Destination Distances by Type of T r i p Made by Callers at a Retail Specialty Store and a Small Service Establishment

52

Maximum Destination Distance and Number of Stops per Block Made by Callers at a Retail Specialty Store and a Small Service Establishment

53

Percentage Distribution of Trips Originating at Residence, According to Purpose of T r i p and Mode of Travel, Portland, Oregon, Internal Area, 1946

73

URBAN

TRAFFIC

A Function of Land Use

CHAPTER

I

Orientation: Land Use and

Traffic Problems in City Planning treats of the relationship between urban land use in its various patterns, and that daily movement of people, goods, and vehicles which we call traffic. It is commonly observed that various kinds of activity based on the land—called land uses— "generate" different amounts and kinds of traffic. It is also observed that a change in the amount of daily movement or in the facilities for it, or an expected change in the traffic at a particular site, has a considerable effect on the locational pattern of the land uses. T h e implications of these observations are of great importance to those who plan and undertake the development of urban land and buildings and to those who provide highways and transit facilities for the city. T h a t is why more knowledge is needed about the precise nature of the relationship between land use and movement and about the extent of their mutual effects. T H I S VOLUME

The Guidance

of Change in Land

Use and

Traffic

A l l cities and urban regions are continually changing, of course, though some change more rapidly than others. These changes may take the form of peripheral extension, the provision of needed utilities and services, or alterations in older areas. T h e change may be dramatic—the building of a major express highway or the large-scale redevelopment of a blighted section, for example; or it may be unobtrusive—the gradual, cumulative result of hundreds of minor actions by individual property owners and municipal officials. In whatever way the changes come about, their total effect may be observed over time in the rise of new neighborhoods or in the blight of old, in the building and extension of business centers, in the spread or rebuilding of slum areas, or in a centrifugal move-

4

ORIENTATION

ment of industry. These trends in land use change should be taken into account by those who make the decisions which produce them. T o a considerable extent the nature and timing of these decisions may be affected by various kinds of public action and control. Under police power are such measures as zoning or subdivision control, and the enforcement of building, fire, sanitary, and housing codes. Other measures include programs of public housing, the provision of industrial facilities, or the redevelopment of blighted areas with the assistance of eminent domain and subsidy. Other public actions, such as those resulting in the provision of services and utilities, and the construction of highways and transit lines, are also used to affect the nature, timing, and location of private development. Some of the measures available to the city planner or public official are direct, and their probable effects are relatively clear. Other measures affect land use change indirectly. T h e y alter the framework within which private decisions are made, and their relative effect is hard to assess. T h e planner knows from experience that a change in traffic channels or habits will affect the pattern of land use, but he cannot tell how or to what degree. T h e planner may wish to use highway and transit planning to help create a desired land use pattern. O n the other hand, he will want to avoid possible undesirable changes in the land use pattern that highway or transit improvement could cause. H e needs, therefore, to be provided with a better understanding of the functional relationship between land use and traffic. Another major concern of the planner is providing for the daily movement of people, goods, and materials through and within the changing city. Planning urban highways and other local transportation channels is a specialized but integral part of total city planning. Highway plans, to be most successful, must be coordinated with plans for land use development and redevelopment and with other elements of the urban structure. T H E THREE STAGES OF URBAN HIGHWAY

PLANNING

T h e development of a sound urban highway and related transportation plan may be divided into three stages. T h e success of the

ORIENTATION

5

results in the second and third stages depend largely upon the quality of planning in the first: 1. A major highway and local transportation network for an entire metropolitan area should be designed in relation to the general plan of the community. A t this stage the design should delineate only in general terms the specific locations and traffic capacity of the various channels. T h e later stages are intended to give greater specificity to these aspects of the plan. 2. Specific route analysis and general plans for individual sections, or channels, in the system should be developed. T h i s stage must be completed before decisions relating to financing and construction can be made. 3. A detailed design of highways and other channels of traffic and of improvements in the existing traffic network should be undertaken. T h e general plan for a metropolitan highway system, as for any element of a comprehensive development plan, is necessarily on a broad scale, without much attention to detail, and somewhat diagrammatic. It deals with major highways—the traffic channels that are of significance to the total metropolitan community. In subsequent comprehensive plans, the particular elements significant to each section of the city are given more detailed attention. From the point of view of between-city or into-city traffic, the entire urban metropolitan network is a terminal system that collects and distributes the long-distance traffic and provides it with terminal facilities. W i t h i n large cities the other function of the urban highway network—facilitating movement among parts of the metropolitan area itself—is much more important because of the volume of traffic. In urban highway planning, therefore, the needs of both kinds of traffic must be taken into account. A local transportation system, including its highway network, is essentially a service system, the function of which is to expedite the daily business of a community through reduction of the "friction of space." T h e capacity of that system may place an ultimate limit on the size of a city's population and the area over which it may spread. It is obvious that the transportation system should be planned as

6

ORIENTATION

a whole in order to serve the city's many activities with the greatest possible efficiency. These activities include the production and distribution of goods; the rendering of services to businesses and to individuals; the advancement of cultural, civic, and political interests; and the daily living and working routines of people. T h e location and capacity of the various movement channels should adequately provide for the amount and direction of movement of people and goods required by these activities. T h e nature, amounts, and locations of the various activities, however, are gradually but constantly changing. O n the other hand, transportation channels are expensive and difficult to change once they are installed. Their obsolescence is usually the most important factor in congestion. This fact poses one of the most important and difficult problems of transportation planning: how to make the most efficient expenditure of capital investments in major highways and other traffic channels by designs which provide for future as well as present requirements. It is apparent that the city planner must consider both sides of the relationship between traffic and land use. If he is chiefly concerned with the land use pattern, he must, nevertheless, consider the potential effect of a change in traffic facilities and habits. If the focus of his attention is upon serving traffic needs, he must be aware that these needs will change if the land use pattern varies. He requires methods of traffic analysis which will take the various effects of this relationship into consideration. Dealing with Urban Traffic at Three

Levels

T h e problems of urban traffic may be dealt with at three general levels. First and most immediate in every city is the regulation and control of traffic within given channels of movement that serve a given pattern of land use. This consists largely of the regulation of direction, speed, turning movements, and of parking and loading. It involves the use of accessory devices, such as traffic signal systems, safety islands, improvement of lighting, and physical provisions for the separation of different types of traffic. Another important phase is safety education and pedestrian control. Closely related is the adjustment of fare structures and schedules of public transit.

ORIENTATION

7

T h e second general level of traffic management is the provision and improvement of physical channels of movement, such as highways and public transit lines, and in the provision and improvement of the accessories to these channels of movement, such as stations, vehicles, terminals, and facilities for parking, loading and unloading, and transfer. This level of action is both urgent and expensive. In most cities, existing channels are critically deficient in providing adequate service even for present-day demands, and as a result, many of the resources available for planning, financing, and constructing traffic facilities are devoted to the amelioration of congestion. T h e third and most basic level of action for a long-run solution of traffic problems is the planning, guidance, and control of change in the pattern of land uses in the interest of efficiency. T h i s change may be guided (within the limitations imposed by other locational requirements) toward reducing the amount and distance of movement necessary between land uses having high rates of mutual interchange, removing gradually from areas of congestion establishments not functionally required to be there, and by separating land uses that generate conflicting or mutually antagonistic kinds of traffic, such as truck and passenger car. In the over-all pattern of land use, it may be desirable to change the proportion of land devoted to movement, parking, and loading. T h e second and third levels of traffic management are not strictly separable because the network of traffic channels and the pattern of location of residential and nonresidential establishments are mutually dependent variables. Change in the land use pattern causes a demand for adjustment in the network of traffic channels, and an improvement in a traffic channel not only results immediately in further locational shifts of establishments and the development of new areas but also increases the amount of movement among areas served by the channel. Tools of Traffic

Analysis

Methods of traffic analysis available at present are reasonably adequate for dealing with the first level of traffic management—its regulation and control within given channels of movement, serving

8

ORIENTATION

a given land use pattern. For the second level—the provision and improvement of physical channels of movement—some of the pertinent questions cannot be answered satisfactorily by present methods of analysis, if at all. 1 T h e third level, that of the planning, guidance, and control of land use change, receives very little assistance from presently available tools of traffic analysis. A t the first level, the primary need is for knowledge of existing traffic on various transportation channels—its amount, peak loads, direction, timing, and flow. Also needed is knowledge of the capacities of channels under varying conditions, requirements for terminal facilities, and probable effects of various regulations and devices. A considerable amount of research has been done to provide the basic knowledge required, and techniques for the requisite local surveys are fairly standard. 2 Present methods of traffic survey and analysis available for system planning, route analysis, and channel design give a fair picture of present conditions. Records of traffic movement by volume and direction over present channels are usually available. Separate data may be obtained for various types of vehicles and for pedestrians. "Typical-day" or "peak-hour" volumes are supplemented by "peakload" counts at critical locations. Extensive or limited surveys to discover the related origins and destinations of traffic are now a part of the standard procedure. In these surveys the places where trips start and end are charted, and the amount of movement between limited areas within the city is tabulated without regard to the routes followed. T h e results are used by engineers in estimating the extent to which new highway improvements are likely to be used by existing traffic and thus, perhaps, by how much the amount of traffic on existing channels will be reduced. 3 1 See H. W. Lockner, "Is Origin-Destination Data the Whole Answer?," in Highway Research Abstracts, XVIII (March, 1948), 23-29. 2 See for example: U.S. Bureau of Public Roads, Highway Capacity Manual (Washington, D.C., 1950); Traffic Engineering Handbook, ed. H. K. Evans (2d ed.; New Haven: Institute of Traffic Engineers, 1950); American Association of State Highway Officials, Institute of Traffic Engineers, and the National Conference of Street and Highway Safety, Manual on Uniform Traffic Control Devices for Streets and Highways (Washington, D.C., 1948); and Daniel O'Flaherty, "Simplified Methods for Travel Studies in Smaller Cities," Proceedings of the Highway Research Board (Washington, D.C., 1947), pp. 297-311. » Highway Research Board, Traffic Assignment (Washington, D.C., 1952).

ORIENTATION

9

T h e older type of origin-destination survey, made by stopping a sample of drivers at portal points of a cordon, is still used for some purposes and has been greatly improved by the combination "internal and external origin and destination traffic survey" (abbreviated O & D) developed in recent years by the Bureau of Public Roads with the collaboration of state and local officials.4 In these surveys a cordon line is drawn around the intensively settled urban area under investigation—usually somewhat beyond the city limits. T h e "external" part of the survey is made by stopping a sample of vehicles passing through the cordon on all major highways in both directions. T h e "internal" part of the survey is made by interview at a sample of all dwellings within the cordon and is for the purpose of discovering information about all vehicular trips of all residents on the day before the interview. Home interviews are supplemented by information procured from truck and taxicab operators. Based upon the "internal" phase of the O & D survey, comprehensive data on a comparable basis are available for the first time on such subjects as purpose of trip, time and day of week, and mode of transportation. T h e data do not include information on the nature of establishments at origin and destination, on routes followed, on pedestrian movements, or on frequency of travel. In general, however, the data present a reasonably complete picture of daily or hourly average movement by individuals, goods, or vehicles utilizing the existing channels within a static land use pattern. T h e O & D method concentrates on straight lines between origin and destination which, in summary, are drawn on maps and called "desire lines." It does not include a record of routes actually followed because up to the present it has been too difficult and expensive to tabulate routes by the business machine method. In the O & D study the survey technique has been much more * T h e O 8c D survey method is well described in a number of publications, including: Robert E. Barkley, Origin and Destination Surveys and Traffic Volume Studies, Highway Research Board Bibliography No. 11 (Washington, D.C., 1951); this study contains a review of the literature and an extensive bibliography. See also John T . Lynch, "Origin and Destination Surveys in Urban Areas," Proceedings of the Highway Research Board (Washington, D.C., 1944), X X I V , 239; and Oregon State Highway Department, 1946—Portland Metropolitan Area Traffic Survey Origin Destination Study (Salem, 1949).

10

ORIENTATION

highly developed than have the methods for its analysis and application. T h i s technique overcomes the principal limitation of older methods, which were based mostly on flow maps: Frequently, total traffic flow—a summation of individual trip routes—reflects the comparative desirability or adequacy of existing routes but does not necessarily indicate the route by which people want to travel. For the purpose of designing for future use of highways, the available data are insufficient. T h e y do not make allowances for land use change or for other changes in the daily activities of an urban area. Without more adequate data, assumptions must be made regarding possible changes in the total volume of traffic—assumptions based upon projections of trends in population, automobile registration, vehicle-miles, and truck use. Reasonably accurate forecasts of the increase in movement or the land use change to be expected from construction of a new channel of movement cannot now be made. Even estimates of the amount of diversion of existing traffic volume to a proposed new channel are little more than informed guesses. T h e methods of analysis which will be useful to the city planner in solving his over-all problems of the land use pattern and its relation to the general highway network will go far beyond the needs of the engineer, who is concerned only with a particular bridge or a stretch of highway. T h e engineer's problem is one of design and takes into particular account peak-hour loads and their variations over time. For example, in studies of Hudson River crossings, engineers for the Port of New York Authority have found that their problem is chiefly concerned with the journeys of commuters going to and from work and that this volume of traffic tends to vary with the activity of the national economy. T h e tunnels and bridges gather their traffic from widespread and diverse areas and serve a cross section of the city's activities. In this kind of problem great precision in measuring the effects of detailed land use change will be of slight value. T h e more general problem, however, remains. Studies of the location and the future capacity requirements of many individual highway and transit projects do require estimates of the effects of land use changes on the total traffic burden and of the effects of a

ORIENTATION

proposed traffic improvement on the land use pattern, particularly in regard to both kind and intensity of use. Summary and

Conclusions

In our constantly changing cities it is the task of the planner to guide the changes toward desired objectives. T h e public official can institute various actions and controls with which he may influence and direct change. He can, for example, determine the location and design of facilities for movement. But to do so intelligently he needs to understand more clearly the possible results of his decisions. He needs to be able to predict more accurately the effects of proposed highway and transit projects on the nature and rate of change in land use. Highways and other channels of movement are very expensive and should serve not only the needs of the time of their construction, but also the anticipated needs of the future. Over-design of facilities to accommodate a volume of traffic in excess of justifiable estimates carries the possibility of unnecessary extravagance. T h e picture of traffic movement which one can be certain will not be representative of the future—that presented by a past survey and its analysis—is the only one available with any degree of precision for present planning. T h e only dynamic analysis possible through present methods relies heavily on the analyst's judgment, which is based largely on empirical observations. T h e range of error in predictions based on such observations, even in predictions made by experienced engineers, is well known. T h e essential task of research in traffic analysis is to seek methods which give promise of greater predictability. Such research should take two major directions: (1) the development of improved methods of local analysis, better knowledge of the kinds of local information needed to supplement existing data, and techniques for data evaluation; and (2) basic research to build a scientific basis for new methods of local analysis. T h e improvement of general methods of analysis is a long-range undertaking. Before such methods can be developed for engineering use, their bases must be explored by means of research along a number of lines, all centering on the dynamics of urban land use.

12

ORIENTATION

T h e goal o£ these studies is to determine the extent to which it is possible to predict the mutual effects of traffic and land use. Obviously, to predict human actions in concrete situations even in large systems, is a goal which at the present time or in the forseeable future may only be approached, or at best attained but rarely. One approach to the problem of predicting the nature and amount of traffic is through research in the movement of people and goods which is associated with kinds or combinations of land use—the principal focus of this study. However, research of this type alone will not answer all the questions. It has not been possible within the limits of this investigation to give more than a passing glance at three other avenues of inquiry. T h e first of these is a study of the allocation of functionally required movement among available channels. T h e present inquiry has dealt to some extent with the collection of data describing people's behavior in choosing a transportation medium. However, to understand this subject considerable study will be required of the motivations that influence the making of choices. T h e second approach to the problem of predictability is a study of the increase in total movement which is due to the provision of a new or more convenient or more pleasant or less expensive channel of movement. Methods and techniques for such a study need further development. 5 T h e third avenue of inquiry is a series of studies concerned with the effect of the improvement of means of transportation upon the location of establishments and upon the amount of activity in which these establishments engage. 6 Some attempt has been made in the present study to explore this subject. It remains, along with many other questions which are introduced in later chapters, a challenge to the curiosity of the future. s T h e Connecticut Highway Department has made some studies of this problem. See Roy E. Jorgensen, "Influence of Expressways in Diverting Traffic from Alternate Routes and in Generating New Traffic," Proceedings of the Highway Research Board (Washington, D.C., 1947), pp. 322-30. « For example, see " A Study of Land Values and Land Use Along the Gulf Freeway," prepared by L . U. Norris Engineering Company for the Texas Highway Department and the U.S. Bureau of Public Roads (Austin, 1951).

CHAPTER

II

Relating Land Use to Traffic

"land use" (used so frequently in planning) has several specific meanings. It may refer to buildings or other improvements on the land, to the occupants or users of the land, to the major purpose of the occupancy of the land, or to the kind of activities on the land. Sometimes the term is employed without being defined specifically. In this study land uses are differentiated by the major activities of establishments based on the land.

T H E TERM

The Changing Nature of Land Use A city is essentially an aggregation of people living with one another, thinking and feeling, cooperating and competing, carrying on business and public affairs. T h e city has an apparent physical structure of buildings, streets, utilities, and open spaces, but behind this are the social, economic, and political patterns into which people are organized and through which they carry on their affairs— patterns of relationship among individuals and among such groups as families, business firms, social, civic, and cultural groups, or government. Some of these individuals and groups serve other individuals and groups in various ways: individuals may make a living by working for business firms; they require a large variety of goods and services; goods are produced in the factories and sold in the stores. These activities of individuals and groups are more or less institutionalized into regular procedures—systematic processes by which things get done. For example, goods are brought into a city and distributed among consumers by organized marketing processes through chains of functionally related wholesale and retail establishments. Likewise, education is accomplished through an organ-

14

RELATING LAND USE TO TRAFFIC

ized school system; a less f o r m a l l y organized medical profession cares for health. T h e s e social, business, a n d g o v e r n m e n t a l institutions are continually and gradually changing, as are the processes t h r o u g h w h i c h they operate. M o r e o v e r , as a city grows i n p o p u l a t i o n and activities, the roles that m a n y individuals and groups play b e c o m e m o r e h i g h l y specialized. ESTABLISHMENTS

AS UNITS

OF

LAND

USE

A l l activities take place o n the land. Individuals, households, a n d business firms r e q u i r e bases f r o m w h i c h to operate. A t these bases they f o r m establishments,

w h i c h are defined for this study as

individuals or groups o c c u p y i n g recognizable places of business, residence, g o v e r n m e n t , or assembly w i t h i n or u p o n units of land. Establishments are also considered to b e units of land use w h i c h may be classified according to their m a j o r activities. T h e spatial distribution of establishments at any o n e time, together w i t h vacant tracts, streets, a n d other common-spaces, constitute the land use pattern of a city. The Change in Urban Patterns Since the organizational relationships and processes of u r b a n activities and the i n d i v i d u a l s and groups w h o m a k e u p the city are c o n t i n u a l l y changing, the f u n c t i o n a l r e q u i r e m e n t s placed u p o n the land use pattern and u p o n the physical channels of m o v e m e n t w i t h i n it are also c o n t i n u a l l y changing. For a variety of reasons, h o w e v e r , it is difficult for the physical city and the land use pattern to change as r a p i d l y as d o the demands made u p o n them. T h e process of urban land utilization

involves three m a j o r steps.

T h e first step is the preparation of a parcel of land f o r " i m p r o v e m e n t " in order to m e e t the needs of an anticipated user. T h i s preparation may i n c l u d e the provision of off-site services and facilities, such as utilities, streets, and transit lines, and may i n v o l v e the demol i t i o n of previous structures on the site. T h e second step is "imp r o v e m e n t " of the parcel b y construction or b y alteration. T h e resulting land-and-improvements constitutes a u n i t of real estate b u t is n o t yet a " l a n d use" i n the sense in w h i c h the term is used

RELATING LAND USE TO TRAFFIC

15

here. T h e third step, by which the physical utilization of the parcel is completed, is the occupancy of the land and building space by one or more individuals or groups to form establishments as bases of operations. Obviously, the occupants may change from time to time without further alteration of the space occupied. Parallel to the physical process of land utilization there may be a series of legal and financial transactions involving shifts in title or tenure. Different people may own the land, construct the improvements, and occupy the space. Each of these steps, some of them involving "long-term" commitments, may be a separate transaction in the real estate market. Usually, various credit arrangements are added to them. Thus, the complex process of land utilization is subject at each step to competition for specific locations among would-be users. It is subject to the delaying effect of prior rights held by many different individuals or groups whose interests may not be in accord with the current competitive situation. Ideally, the physical structure of a community should serve not only the direct needs of individual users but also the requirements of the community as a functioning unit—one which, like all functioning units, needs articulation of its various parts for amenity and efficiency of operation. This additional interest has not often been faced squarely by land economists, who have generally assumed that thousands of decisions made by land users to serve their private ends will somehow, by laissez faire, combine to serve the common interests of all land users as a community. Actually, the extent to which this assumption is correct is not known from empirical study, but in practice a need for public measures, such as zoning to guide and control individual decisions in accordance with some accepted community land use objectives, has been recognized. Is it any wonder, then, that the land use pattern adjusts slowly to the needs of most individual users seeking locations for their bases of operations? There is an inevitable lag in the adjustment of a land use pattern to changes in the organization and processes of urban activities. In the long run the adjustment tends to occur, but pressure for change always precedes it. Thus far, relatively few devices are available to expedite the adjustment process.

RELATING LAND USE TO TRAFFIC

i6 The Locational

Requirements

of

Establishments

T h e present study suggests many questions which cannot be answered on the basis of present knowledge. O n e of these questions is suggested above: H o w does the movement of people and goods, or the need for such movement, act as a factor in determining the locational requirements of various kinds of establishments? A second question follows: T o what extent are these locational requirements reflected in actual establishment locations? These questions cannot yet be answered because the necessary research has not been done. T h e objective of this study is to suggest an analytical framework which may help to guide further study in this direction. In constructing this framework it has been necessary to consider the components of land use—individuals and establishments in action. W e shall go on to suggest that movement can be observed most fruitfully as movement to, from, and among establishments as bases of operation and as destinations, in any inquiry into the relation between land use and movement. The Nature

of

Traffic

Every automobile driver is conscious of the growing volume and complexity of traffic. T o him traffic is composed of vehicles either moving or waiting to move. Other automobiles, taxicabs, trucks, motor buses, and trolley cars compete for limited street space. W i t h i n these vehicles people are traveling (one or many in each vehicle) and goods and materials (of many kinds and in varying quantity) are being hauled. In some cities people and goods are being transported above and below the street surface in elevated and subway trains; and there are always pedestrians. Obviously, the concept of "traffic" needs specification for a study that attempts to encompass all of these components. As already indicated, traffic is the movement of vehicles transporting persons and objects whose movement is required for the interaction of establishments and individuals. Analyzing the factors that produce traffic is even more complex than analyzing the movement of persons and goods, for the amount and the type of traffic are a result of persons- and goods-movement, and a multitude of indi-

RELATING LAND USE TO TRAFFIC

17

v i d u a l choices d e t e r m i n i n g w h i c h means a n d w h i c h channels of transportation w i l l be used. Components in the Analysis of Traffic If analyses of the determinants of traffic are to be made, they must take i n t o account the various c o m p o n e n t s of traffic w h i c h r e q u i r e separate study. It is necessary, that is, to distinguish b e t w e e n the determinants of the various observable systems of persons- a n d goods-movement and the factors that d e t e r m i n e the choice of a m o v e m e n t channel. T h e basic determinants of persons- and goodsm o v e m e n t m i g h t b e expected to b e f o u n d in the a m o u n t and the n a t u r e of activities carried o n i n the daily life of a city. SYSTEMS OF URBAN ACTIVITIES

T h e activities characteristic of a city r e q u i r e the m o v e m e n t of b o t h persons and goods to and f r o m and a m o n g the establishments w h i c h serve as bases of operations. T h e absolute a m o u n t and the n a t u r e of this m o v e m e n t are d e t e r m i n e d b y the nature and v o l u m e of u r b a n activities. T h e activities i n t u r n may b e v i e w e d as resulting f r o m (1) the existence of certain basic and relatively invariant needs plus other needs or r e q u i r e m e n t s w h i c h change f r o m t i m e to time, (2) the organizational structure of interacting i n d i v i d u a l s

and

groups, and (3) the institutionalized processes—customary manners and routines of a c t i o n — w h i c h these i n d i v i d u a l s and groups e m p l o y . T h e activities characteristic of a city f o r m systems of action. Some of these systems of action (for e x a m p l e , the b o t t l i n g and distribution of m i l k ) are m u c h m o r e integrated and r o u t i n i z e d than others (such as the seeking of entertainment), and therefore the trends in movem e n t are m o r e predictable i n some systems than in others. T h e basic factors in the a m o u n t a n d n a t u r e of m o v e m e n t are f o u n d in the a m o u n t and n a t u r e of u r b a n activities (as systems i n u r b a n activities can b e discerned). B u t m o v e m e n t is also affected b y the locational pattern of establishments and b y the relative ease of travel, for these d e t e r m i n e n o t only w h i c h establishments, o r w h i c h groups of establishments, w i l l have relationships w i t h o n e another, b u t w i l l d e t e r m i n e also the degree of their interaction a n d the f r e q u e n c y of the m o v e m e n t b e t w e e n them.

i8

RELATING LAND USE TO TRAFFIC

I n passing it is w o r t h o b s e r v i n g that analysis of the systems of u r b a n activities suggests another proposition: the a d e q u a c y of the physical channels of m o v e m e n t of a city partly determines the a m o u n t of activity a n d thus the social and economic integration a n d the vitality of the city. T h e r e f o r e it m a y be said that the a m o u n t and nature of the m o v e m e n t of persons and goods to and f r o m an establishment (or a g r o u p of establishments) are affected in v a r y i n g degree b y f o u r factors: the n a t u r e a n d size of the establishment, its position a n d f u n c t i o n in the u r b a n organization, the spatial relationships between the establishment and other establishments in the land use pattern, a n d the existing channels of m o v e m e n t as related to the establishment. T H E STRUCTURE OF T R A F F I C

A l l the m o v e m e n t r e q u i r e d b y the activities of a c o m m u n i t y is translated into the structure

of traffic—the

result of choices m a d e

in d e t e r m i n i n g the m o d e of transport (for e x a m p l e , to drive or to use a p u b l i c transit facility), the r o u t e or channel of m o v e m e n t , and the time of travel. 1 T h e s e elements of the structure of traffic are interrelated, of course, b u t for analytical purposes they may be considered separately. T h e structure of traffic f r o m the p o i n t of view of its d i s t r i b u t i o n in time a n d space (its relative density at various locations at particular times) is d e p e n d e n t u p o n h o w m a n y p e o p l e choose to m a k e use of a particular m o d e or r o u t e of travel at a particular time. T h u s , i n constructing an analytical f r a m e w o r k w i t h i n w h i c h to study the relationships b e t w e e n land use and traffic, it is necessary to take i n t o consideration the structure of m o v e m e n t , its characteristics (and possible ways of m e a s u r i n g them), a n d its components, as w e l l as its organization into m e a n i n g f u l systems w h i c h m a y b e related to the organized activities of the c o m m u n i t y . It is also necessary to consider the n a t u r e of i n d i v i d u a l m o v e m e n t s and their relationship to the mass m o v e m e n t . A p p e n d i x B gives an idea of the n u m b e r of different items w h i c h m i g h t be taken i n t o account. i In this study "structure" is used in the sense of a complete picture (i.e., of traffic or of major components of movement) of a given area at a specific point in time.

RELATING LAND USE TO

TRAFFIC

!9

Summary

T h e pattern of land use reflects the locational requirements of a multitude of individual land users. It also reflects the requirements of the whole community for articulation of its activities into patterns making for efficiency and amenity. Both sets of requirements are factors in the composition, organizational structure, and institutionalized processes of action in the community. T h e influence of these factors in the determination of the land use pattern is limited by conditions imposed by the actual process of land utilization and by formal and informal community controls. In any study of the relationships between land use and traffic, the concept of land use is made more meaningful if consideration is given to the components of land use and to the individuals and establishments participating in organized systems of action. It should be remembered also that the amount of traffic in a city (i.e., the number of vehicles in the traffic stream plus the total traffic of the public transportation media) is a reflection of the total movement of people and goods through the various channels of movement. Thus, underlying the functional relationship of traffic and land use is the movement of persons and goods among establishments—a manifestation of various systems of urban action.

CHAPTER

in

The Structure of Movement:

Spatial and Temporal Organization of persons and goods may be studied in terms of the characteristics, components, and organization of movement in the mass, or in terms of the nature and properties of individual movements. In developing the analytical framework presented in this chapter the main focus has been on movement in the mass. It must be remembered, however, that mass movement is composed of individual movements and that some understanding of individual movement will throw light on the most productive way of looking at the mass phenomenon. The way to link the two approaches is to consider individuals and establishments in their various social roles, which taken together constitute the larger systems of action in the city. This scheme recognizes the sociologists' distinction between the individual's acting as a rounded person and the individual's acting in a role, that is, in a specialized capacity in a system of patterned relationships—the social structure. 1 The structure of movement for any geographic area (such as a business district) or channel of movement (such as a highway or a transit line) consists of all the phenomena, including the multitude of individual movements and their interrelationships with other movements, individuals, establishments, and places, that are observable at a particular time. Supposedly, this structure may be described in terms of an infinite number of characteristics and dimensions. One might conceivably detail the movements of all thirty-five-year-old males wearing blue suits and driving blue automobiles with white-wall tires. Actually, however, the description of a structure of movement for an area is most likely to be in terms T H E MOVEMENT

1

For example, Talcott Parsons, Essays in Sociological (Glencoe, 111., 1949), p. 34.

Theory

Pure and

Applied

THE STRUCTURE OF MOVEMENT

21

of composition, volume, distance, time, rhythms, location (such as areas of concentration and dispersal, routes, and physical channels), density, kinds of trips, and kinds of establishments at destinations and bases. T h e characteristics of the moving persons or goods may be pertinent. Such a description would give a picture of the total movement within a given period of time, but the description would vary with time. Although the structure of movement is concrete and is pinned down in time and space, a hypothetical structure, under given assumptions, may be constructed. It will be the task of research to discover what assumptions are pertinent and how they may influence a hypothetical structure of movement constructed as a basis for planning and design. Operating within the structure of movement of persons and goods within a given area are functionally organized systems of movement. These systems are said to be functional because they serve, or are functionally related to, organized systems of business or social action. They are kinds of movement and may be defined in terms of volume per representative unit of time without regard to absolute time or location. The daily movement of persons from home to work is such a system. Daily movement from home to work in a central district is a system related to an area of assembly. T h e daily home-to-work movement of salespersons in central-district retail stores is a subsystem based upon kind of establishment and occupation. In this chapter we shall consider the characteristics and measures of movement that may be useful in analysis, as well as the forms of mass movement and its spatial and temporal characteristics. Attention will also be given to components of the structure of movement —the nature and significance of individual movements of persons, goods, and vehicles which may be discovered within the total structure. In succeeding chapters we shall explore and analyze these components of the structure of movement and systems of movement in great detail. Forms of Mass

Movement

T h e movement of both persons and goods has three basic forms. T h e first form is an assembling movement, a converging on points

22

THE STRUCTURE OF

MOVEMENT

or areas of assembly. Goods of various kinds are assembled at factories for processing and packaging, at warehouses for storage, at terminals for change of transportation, and at various establishments in the marketing process for sorting, resale, and delivery. Individuals assemble at stadiums or other points for meetings, at establishments or business areas where they are employed, at shopping and service areas for transactions of various kinds. A variation in this form of movement is assembly by stages, in which assortments of goods or persons, previously assembled elsewhere, are brought together. The second major form of movement is dispersive movement, in which goods or persons are dispersed from points or areas of assembly throughout related areas of dispersal. Examples of this form of movement are the movement of goods from a final retail sales establishment to the location of final consumption and the movement of persons from a stadium or a large factory to dispersed locations of residence. The third form may be called random movement, in which goods or persons travel among dispersed locations. From the point of view of small individual establishments these movements might be classified as either assembling or dispersive. In the whole volume of urban movement each of these movements between small establishments is relatively insignificant. Taken in the aggregate, however, they are significant. Each of the three forms of movement may be discerned within the identifiable, related systems of movement, whether of goods or of persons, and these systems become key categories in the organization of the structure of movement. Although these systems can also be characterized as assembling, dispersive, or random, there are basic differences between them and the forms of movement of goods and persons. Goods are more or less expendable. Over a period of time they are consumed. Except for some kinds of goods-movement, such as those in which tools or equipment are moved around from job to job, most goods-movement systems are one-directional. Goods flow from point of origin to point of use or consumption, or from point of use to point of disposal. On the other hand, persons move about

THE STRUCTURE OF MOVEMENT

2$

from place to place, returning periodically to their various bases of operations. T h e stream of travel created by the movement of persons from home to work and back is like the ebb and flow of the tide. A housewife who goes shopping in a department store eventually returns home. T h e businessman who makes a sales call on a customer eventually returns to his office. If movements of goods to and from a shopping area are mapped, it will be found that the origins of inbound movement are different from the destinations of outbound movement and that the latter type of movement will be much more dispersed. But if movements of persons to and from a shopping area are mapped, it will be found that the origins of inbound movement and the destination of outbound movement are usually the same, except for some trips between bases such as home and work where the shopping stop was incidental. Whereas most goods flow is one-directional, most persons-movement (including interbase trips, such as trips to and from work) has the nature of a round trip. Only a very few systems of goods-movement, such as the circulation of library books, approximate the nature of most persons-movement. Goods-movement systems of this type are treated separately in the discussion of goodsmovement systems in a later chapter. T h e movement of individuals among, or to and from, their bases of operations is the most obvious distinguishing characteristic of persons-movement. These bases of operation are focal points from which to measure and describe personal movement. Although individuals change their bases of operations from time to time, as they move from one house, or one job, to another, these changes are relatively infrequent. T h e destinations to which people travel from day to day vary considerably. Spatial Characteristics Amos Pennyfeather lives with his wife and children in a Cape Cod ranch house in the suburb of Upsal Downs. Although he may not realize it, his home constitutes an establishment which is a residential base of operations for each member of his family. Each morning Amos is driven by his wife to the suburban station where he takes the 8 : 1 5 to town. From the train terminal he walks a couple

24

THE STRUCTURE OF MOVEMENT

of blocks to his office in the central district of the city. T h e office is another establishment of which Amos is a member, and serves as his work base. A great many other people converge on the same office at about nine o'clock. For all the individuals in this system of movement the office is a point of assembly. T h e central business district within which the office is located is an area of assembly for workers from scattered locations in the urban area. Another system of movement converges on the same area of assembly as the shoppers arrive. Goods to be used or sold are also moved to this area of assembly from factories, warehouses, and terminals. A R E A S OF A S S E M B L Y

AND

DISPERSION

For analytical purposes either an entire area, such as a central business district, or some section within it may be considered as an area of assembly for persons, goods, or vehicles. In Figure 1 the entire central district of Philadelphia is shaded. Within this district one subzone, for which data were tabulated in the 1947 traffic survey of the Philadelphia-Camden area, 2 includes about two blocks of frontage on Chestnut Street, part of a major shopping center. If the subzone (00062) is considered as an area of assembly, the residences of persons making trips to that subzone are located within a related area of dispersal. Figure 2 illustrates an area of assembly for goods—the Port Richmond industrial area in Philadelphia. T h e dots represent points of origin of truck trips to it, and the width of the line at interview station points on the survey cordon line indicates the number of trucks coming from outside the survey area into this area of assembly. Within an area of assembly, such as a trading or amusement district, the existence of a variety of establishments at which people can find a large number of opportunities to satisfy their needs on one trip, or can compare offerings in a number of shops before pur2 Pennsylvania Department of Highways and New Jersey State Highway Department in cooperation with the Bureau of Public Roads and the Philadelphia City Planning Commission, Philadelphia-Camden Area Traffic Study (Philadelphia, 1950), Vols. I and II.

Philadelphia City Planning Commi»sion PLANNING SECTIONS

FIGURE I . RESIDENCE OF PERSONS MAKING

T R I P S TO SUBZONE

00062

26

FIGURE 2 .

T H E

ORIGINS OF T R U C K RICHMOND

STRUCTURE

TRIPS

WITH

INDUSTRIAL A R E A ,

OF

DESTINATION

PHILADELPHIA,

M O V E M E N T

IN T H E

PORT

PA.

Source: Philadelphia Camden Area Traffic Survey, 1950

chase, is in itself an attraction to the area. T h e related establishments in such an area reinforce one another in attracting trade.3 T h e analyst may wish to determine the extent of an area of assembly which is related to a particular establishment. T o do this he may find the area within which are located all the establishments visited by persons on the same trip from a base of operations. Figures 3, 4, 5, and 6 illustrate areas of assembly in the Philadelphia Central District and the relationships of various establishments in the area to four selected establishments: a department store, a specialty shop, a theater, and a shoe repair shop. T h e data were secured by interviewing a sample of all persons calling at these establishments during a working day. A l l dots on these maps indicate s T h e human ecologist calls this relationship commensalism. See Amos H . Hawley, Human Ecology, A Theory of Community Structure (New York: Ronald Press, 1950), p p . 39 ff.

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fied thus: (1) movement within the marketing process, including production, distribution, and consumption; (2) movement incident to construction, maintenance, and repair; (3) movement incident to waste disposal and salvage; (4) movement incident to change of location of groups occupying or constituting establishments; and (5) other movement of special kinds. Probably the largest and most significant of these groups of movement systems are those in the marketing process. A n approach to their analysis is afforded by study of marketing channels and factors determining or affecting them, including the nature of middlemen in the process, the degree of vertical integration within channels, and the nature of commodities handled. Meaningful classifications of commodities for analytical purposes remain to be worked out. Most existing lists have been developed in connection with rate schedules, and the rough classifications used in marketing studies are not yet satisfactory.

CHAPTER

VII

The Influence of Movement on Land Use Patterns

S P A T I A L A R R A N G E M E N T of establishments emerges from the character of their mutual relationships and their relative positions and functions in the urban organizational structure. In a broad sense relationships (communication of one order or another) between establishments form a network over the urban scene. Every establishment must have some contact with others if it is to operate. Establishments vary in the number of contacts with others, and in the regularity and frequency with which these contacts occur. Within establishments the relative importance of some relationships will be considerably greater than that of others. If contacts through intermediate establishments are included, the network of relationships can be made to extend over the nation and across the face of the globe. For the purposes of analyzing the patternization of urban land uses, however, consideration must be limited to relationships that occur in a given urban area. There will be an attempt on the part of a given establishment to achieve maximum accessibility to others with which it interacts, if there is the need for face-to-face contacts of persons or for the movement of goods between them. This can be done by locating proximately, or along physical channels of movement that provide ready accessibility. Since each establishment has a number of ties to others that may be scattered spatially, it will be pulled in different directions. The ties or group of ties of greatest significance to the operation of the establishment will be an important determinant in the choice of location. Thus, relating movement of persons and goods to the location of an establishment and examining movement as a factor in the spatial distribution of establishments are not two problems but two aspects of the same problem. The locational choice of T H E

MOVEMENT AND LAND USE PATTERNS

105

an establishment is governed (among other things) by the location of other establishments and by the existing channels of movement. Essentially, movement as a locational force is reflected in an attempt on the part of an establishment to minimize the amount of movement necessary between it and other establishments with which it engages in transactions. Expressed in dollar terms, minimization of movement cost is not necessarily based upon distance or time, but upon variations in the cost (e.g., classified freight) of transporting goods or persons to and from the establishment. There are, of course, many factors and forces that prevent the optimum arrangement of land uses toward this end. Some of these relate to the type and availability of space at a given location, rent levels and land values, and cost of relocation. Others include such factors as tradition, inertia, long leases, legal limitations on use, and imperfect knowledge. An establishment may find that no space is available at its optimum location, that the available space is not suited to its use, that there are legal and social restrictions on its use, that rents or land values are too high, or that the cost of relocation exceeds the savings that may be effected. It may also be bound to its present location by a long-term lease or by inertia or tradition. Although attention in this study is focused on the manner in which the necessity for movement among establishments influences the locational distribution of land uses, this should not convey the impression that the other factors are of little, or even of lesser, importance. In fact, it is essential that allusion be made to these factors in the course of the development of the discussion. Major consideration, however, will be given to movement as a strategic factor in the determination of location and in the shaping of land use patterns. T h e first part of this chapter, then, discusses how movement systems relate to the location of establishments: Given the locational configuration of establishments and movement channels, why did certain types of establishments select their existing sites? What types of use tend to form cohesive groupings and what types tend to adhere to others? T h e second part of the chapter is concerned with dynamics: What are the forces that make for changing movement requisites and how do they influence the pattern of uses?

io6

The Vocational

M O V E M E N T AND LAND USE PATTERNS

Role of

Movement

T h e way in which the movement of persons and goods influences an establishment's choice of location is related to its functions and activities. It was previously stated that an establishment consists of a bundle of activities, each of which has its own particular movement requirements. Corresponding to these requirements are locational requirements, which conceivably may be the same for all activities of an establishment but which will usually show more or less variation. Unless an establishment is completely subdivided by function, only one location can be chosen. T h e choice of this location, other things being constant, will be governed by the function (and its corresponding movement associations) that is of primary importance to the establishment. Since the nature of the necessary movements associated with the primary function is the determining locational factor, it must be analyzed in some detail. One of the most fruitful ways of approaching the problem is to examine the movement systems that are related to the establishment in question. It has been suggested that systems of movement are basic instruments for analyzing the relationship between movement and land use. Systems are essentially abstractions and to be given substance they must be meshed with the location of establishments to which they refer. T h i s process takes the form of analyzing systems by type of trip in order to discover the type of trip that is associated with the primary function and the manner in which its characteristics influence the location selected by the establishment. J u s t as there are many activities conducted by an establishment, there is similarly a packet of movement systems associated with each activity and, of course, with the primary activity. An establishment engaged in the selling of goods will serve as the non-base destination for persons on round trips or as an intermediate destination for persons on interbase trips. For persons employed at the establishment, it will be a base for home-to-work trips and for round trips made during the course of the workday or on lunch hour. As a nonbase destination, movement to the establishment may consist primarily of visitors who are members of the general public, or it may

MOVEMENT AND LAND USE PATTERNS

107

be comprised of a highly specialized type of clientele. Although each of these systems may have conflicting locational requirements, the primary activity will determine the set of movement systems that are accommodated in the final choice of location. A single location, however, may be eminently suited to more than one activity. A department store that is centrally located may be readily accessible as a destination for round trips, as a non-based destination for home-to-work trips, or as an incidental stop in the course of a compound interbase trip. It will also provide accessibility to its employees on home-to-work trips. In analyzing the primary function in terms of movement systems, these focal questions are to be asked: What types of trips are involved in the movements associated with the primary function? Does the establishment serve its primary function as a base or as a destination, or both? If it is a destination, is it a primary destination or an incidental stop? What is the locational distribution of establishments that are trip origins if the primary function operates as a destination, or of trip destinations if the primary function operates as a base? If establishments which serve as origins or destinations for a given establishment are widely dispersed, then accessibility cannot be in terms of proximity; it must be expressed in terms of a central location that is readily accessible to all of these establishments. Here the choice of location is governed by the nature of the channels of movement. If the establishments that serve as origins or destinations are confined to a small area then accessibility can be achieved through proximity. Department stores, other outlets for shopping goods, banks, and other types of businesses that are in large measure primary destinations for persons on round trips and that have an area of dispersion widely scattered throughout the city tend to locate at places where passenger traffic facilities converge. Similarly, types of businesses that require the services of employees with specialized training or skills also seek central locations. Conversely, less specialized branches of trade and service, which have more concentrated areas of dispersion, distribute themselves outside the main shopping centers and are thereby more accessible to buyers in one section of the

io8

MOVEMENT

AND LAND USE PATTERNS

city. Convenience-goods establishments, which for the most part are visited incidentally in the course of a round trip or an interbase trip seek locations at important traffic intersections and along principal streets in all sections of the city. Establishments which are devoted mainly to the handling of large quantities of goods and which are both destinations and origins for goods shipped into and out of the city tend to locate in the transport zones of urban areas—the waterfront, at sites along railway lines, and in the terminal and switching districts. T h e industrial zone in large cities "is neither compact nor particularly central, but stretches out along water ports, radial rail lines, and belt railways." 1 Establishments that handle goods of less bulk that can be shipped by truck, the destinations of which are either scattered about the city or concentrated in the central business district, tend to locate on the fringes of the downtown area. The Friction

of Space

Up to this point, movement has been discussed only in terms of distance and time. In actuality the calculation is made in money terms—the cost of shipping goods and transporting persons, plus the time cost of moving persons. In this total, goods-movements will carry a heavy weight if there is a high goods-persons ratio, and persons-movement will be heavily weighed if the reverse is true. But transportation cost is not the only economic consideration. According to Haig, accessibility means "contact with relatively little friction." 2 Reducing the friction of space involves two classes of costs: the cost of transportation and the cost of site rentals. Haig maintains that these are connected phenomena: "Rent appears as a charge which the owner of a relatively accessible site can impose because of the saving in transportation costs which the use of the site makes possible." 3 Central sites afford maximum accessibility but these are limited in number. Establishments and activities which can make the greatest savings in transportation costs will bid 1 Edgar M. Hoover, The Location of Economic Activity (New York, 1948), p. 128. 2 Robert Murray Haig, Regional Survey of New York and Its Environs (10 vols.; New York, 1927), I, 38. s Ibid.

MOVEMENT

AND

LAND

USE

PATTERNS

log

u p t h e r e n t a l s f o r these sites, 4 a n d o t h e r s less a b l e t o p a y w i l l b e c o m p e l l e d to u t i l i z e less a d v a n t a g e o u s l o c a t i o n s . " T h e t w o e l e m e n t s , t r a n s p o r t a t i o n costs a n d site r e n t a l s , " H a i g has t e r m e d "costs of friction."

5

C h a m b e r l i n , h o w e v e r , takes issue w i t h H a i g ' s d e f i n i t i o n , a t least i n r e g a r d to r e t a i l uses: . . . rent is not paid in order to save transportation charges. It is p a i d i n order to secure a larger v o l u m e of sales. Buyers and sellers alike are scattered over a wide area. M o v e m e n t a m o n g them is so impeded that one place w i t h i n the area gives advantages in securing the custom of a portion of the buyers. It affords a market w h i c h is, to a degree, distinct f r o m the whole. T h e a m o u n t of product each seller can dispose of is n o t indefinitely large at the prevailing price. It is very definitely limited by location; if it were not, department stores w o u l d locate in o u t l y i n g districts, securing the same v o l u m e of business, and increase their profits b y the saving of rent. If we regard the whole area as one market it is clear that rent is paid because it contains elements of monopoly. Spatial differentiation results in d e m a n d curves w h i c h have a negative slope instead of being perfectly horizontal. 8 T h e s e seemingly contradictory views m a y b e reconciled b y refere n c e to t h e r o l e t h a t t h e f r i c t i o n of space p l a y s i n t h e p r o d u c t i o n 4 In the Loop district of Chicago the aggregate value of land in 1926 was one fifth of the total for the city, an area one thousand times as great as the central business district. Homer Hoyt, One Hundred Years of Land Values in Chicago (Chicago: 1933), pp. 336-37. Peak values in New York City in 1927 were to be found on Broadway, and on State and Madison in Chicago in 1930. R. D. McKenzie, The Metropolitan Community (New York: 1933), p. 234. In St. Paul maxifnum land values were at the principal points of traffic convergence. Calvin F. Schmidt, "Land Values as an Ecological Index," Research Studies of the State College of Washington, March, 1941, pp. 31-36. Similarly, at the turn of the century land values in the business sections of Council Bluffs, Salt Lake City, Duluth, Seattle, Atlanta, Toledo, Columbus, Richmond, Kansas City (Missouri), and Minneapolis were highest at the main traffic intersections. Hurd, op. cit., pp. 134-43. According to Spengler the effect of the construction of a new transit facility is neither direct or uniform. In his study of the influence of subway construction on land-value trends in New York, he concludes that "In some cases . . . land value changes . . . along or near traffic arteries . . . have been found to exceed 1,000 per cent. In others, actual losses have been experienced. . . . Moreover, in a large number of areas there has been a kind of indifference to the presence of transit facilities, the value of land along such routes behaving in no different manner than that for an entire section of which it is a part. . . . A transit facility . . . permits . . . an emergence of land values, the values being determined largely by other factors." Edwin H. Spengler, Land Values in New York in Relation to Transit Facilities (New York, 1930), pp. 130, 133.

5 Haig, op. cit., I, 39. • E. H. Chamberlin, The Theory of Monopolistic 1942), p. 215.

Competition

(Cambridge, Mass.,

1 10

MOVEMENT

AND LAND USE PATTERNS

functions of different types of establishments. Space, on the one hand, may be considered as an input factor that enters into the cost relationships in terms of rent, transportation, time (labor cost), etc.7 On the other hand, space can also be considered in terms of output; that is, a firm not only sells goods and services but also convenience. In this sense alternative locations will have different influences on the level of the demand curve, with more accessible locations tending to raise the curve, and less accessible locations tending to lower it. Here, too, the strategic factor is movement expressed in transportation cost. T h e cost, however, is not incurred by the establishment but by the persons who visit it. Cost to the visitors must include such elements as time, convenience, and pleasantness as well as dollar outlay. O n the whole, the relative importance of these input and output factors in the operation of specific kinds of enterprises constitutes a significant factor in the locational distribution of activities in an urban area.8 It should be noted that in most cases in which location is related to cost, the establishment's principal activity in terms of movement is as a base of operations. In those cases where location is related to demand, the principal activity centers around the establishment as a destination of one type or another. Linkage

and

Proximity

Factors that lead establishments to seek proximate locations serve to explain the clustering of uses that is characteristic of urban land use patterns. For certain types of movements and for certain classes of establishments, a high premium is placed on time (as an influence on cost or demand). When this is the case, interacting establishments require locations that are adjacent or in close proximity. T h e necessity for face-to-face contacts in the financial district and the large sums of money involved in transactions tend to keep financial institutions and their corporate customers within short walking 7 In this regard Walter Isard suggests the incorporation of a new factor in the production function. T h e new factor is "distance inputs," a mode of indirect labor, the price of which is measured in terms of transportation rate ("Distance Inputs and the Space Economy," Quarterly Journal of Economics, L X V (May and August, 1951), 181-98, 373-99. s It is assumed in this study, however, that establishments have already made their compromises between cost or demand factors and rent.

MOVEMENT AND LAND USE PATTERNS

1 1 1

distance of each other. In the garment center, the prevalence of subcontracting, the rapid adjustments in p r o d u c t i o n that must be m a d e i n response to changes in fashion, a n d variation i n orders also dictate tight spatial integration. W h e n this is c o u p l e d w i t h the n e e d f o r p r o x i m i t y to local outlets as w e l l as the c o n v e n i e n c e to out-oft o w n buyers, the present location of the garment center in N e w Y o r k is readily understood. C o m p a c t groupings such as these m a y be said to reflect the great n u m b e r of linkages a m o n g the clustered establishments. L i n k a g e , then, may be defined as a relationship b e t w e e n establishments characterized b y c o n t i n u i n g or f r e q u e n t l y r e c u r r i n g interaction. It is associated w i t h the m o v e m e n t of persons and goods b e t w e e n the l i n k e d establishments and generates a tendency o n the part of l i n k e d establishments to seek p r o x i m a t e locations. 9 T h e examples b e l o w present illustrations of the various types of l i n k a g e w h i c h may be delineated. 1 0 Establishments are l i n k e d if they participate in transactions inv o l v i n g the m o v e m e n t of persons and goods. A m a c h i n e repair shop and a factory that it serves are linked establishments. T h e smaller concern w o u l d tend to m o v e toward the larger, particularly if the smaller is the supplier and the larger is the customer. In cases of this sort the factory may be considered as a dominant m a c h i n e shop may be characterized as a subordinate

use and the use. A domi-

n a n t land use may also consist of a g r o u p of similar establishments, n o one of w h i c h is d o m i n a n t in itself (garment center i n N e w Y o r k ) . T h e g r o u p of establishments taken together, however, constitute a d o m i n a n t use. T h e m o v e m e n t b e t w e e n d o m i n a n t and subordinate uses consists of interbase trips in w h i c h the individuals operate in their roles as m e m b e r s of their respective establishments. 9 T h e concept of linkage presented here is similar to that suggested by Professor Florence. He says that "owing to intransportability of semi-manufactured materials or products or to the need of contacts for the interchange of knowledge, there may be linkage with the makers of a particular product or a variety of products." He further points out that if one of two linked industries is dispersed, the other will also tend to be dispersed (i.e., tend to have the same coefficient of localization). T h u s , although he does not state that establishments of linked industries will be proximate, it is reasonable to draw such an inference on the basis of the agreement between their localization coefficients. P. Sargant Florence and W. Baldamus, Investment, Location, and Size of Plant (Cambridge, England, 1948), p. 180. 10 For suggested indexes of linkage, see pp. 150-54.

112

MOVEMENT AND LAND USE PATTERNS

Linkage exists when an establishment serves the members of another establishment. Thus a restaurant or a barber shop near a large industrial plant draws its customers predominantly from the workers in the plant. Despite the fact that there may be no direct transactional relationships between the restaurant and the plant as establishments, nevertheless consistent and routinized personsmovement exists between them. The plant, in this case, may be considered as a dominant use, while the smaller establishments may be termed ancillary uses. Ancillary uses may be non-base destinations for round trips, or incidental stops on interbase trips. In these cases, the individual moves in a personal role, and not as a member of an establishment. Establishments are linked if they serve common customers. Macy's and a small specialty shop located on Thirty-fourth Street in New York City have customers in common. It is evident that a larger proportion of the customers of the specialty shop will also be customers of Macy's than vice versa. Macy's, by virtue of its great variety of merchandise, is able to attract large numbers of people, and the specialty shop capitalizes on the traffic. In this case Macy's may be considered as the dominant use and the specialty shop may be termed a satellite use. Macy's and Gimbels, however, by virtue of the fact that each can attract large masses of people in its own right, cannot be considered to be in dominant-satellite relation to each other. Macy's and Gimbels, having equal importance, can be termed codominant. Satellite uses are, as a rule, incidental stops for round trips destined to the dominant use. Codominant establishments may both be of equal importance as a destination for a particular trip, but in many instances one becomes an incidental stop for trips that have the other as their primary destination. Proximity among establishments frequently exists for reasons other than linkage. Establishments which are proximate but not linked may be considered as noncomplementary land uses. In fact, the side-by-side existence of nonlinked establishments may militate against each other's interests. For example, an establishment requiring the regular movement of a large volume of goods will im-

MOVEMENT

AND LAND USE PATTERNS

1 13

pede the operations of a next-door establishment that requires ready access to a large number of persons. Noncomplementary land uses which are not linked but which at the same time do not interfere with each other's movements may be termed compatible. Noncomplementary land uses which interfere with each other's operation may be considered incompatible. In actuality, however, few noncomplementary uses will be entirely compatible or incompatible. Consequently, these cases should be classified according to their degree of compatibility, i.e., the extent to which they interfere with each other. In the illustrations below, characterizations of compatibility are to be considered as indications of the section of a scale in which the cases are likely to fall, rather than as absolute designations. Establishments may be attracted to the same address or locality because of prestige reasons. Insurance companies and the Curtis Publishing Company occupy space in the vicinity of Independence Square in Philadelphia because of a desire to be associated with an important historical symbol. Before Curtis moved its printing and distribution operations to Sharon Hill, these uses were incompatible. Now that only some of the editorial offices are maintained at Independence Square, the establishments may be considered compatible. Curtis Publishing Company on the masthead of The Saturday Evening Post still gives its address as Independence Square, Philadelphia. Establishments may tend to proximity because they require space with the same or similar physical characteristics or rent levels. A n accountant and a wholesaler without stocks may locate in the same building despite the fact that they may never deal with each other. Establishments in this category will tend to have similar types of operations. These are compatible uses. Establishments may locate close to each other because they require the same general location. The New York Times and the Paramount Theatre are at Times Square for reasons of accessibility to a widely dispersed population. T h e Times wishes to be able to send its reporters and distribute each edition to all sections of town as expeditiously as possible. T h e Paramount wishes to be accessible

114

MOVEMENT AND LAND USE PATTERNS

to as many customers as possible. Because it shows first-run films and features prominent entertainers, its market is the entire city, not just one neighborhood. During the late evening hours when the newspaper trucks are loaded and dispatched at the same time that crowds are pouring out of the theaters, these uses are incompatible. (At 5:00 A.M., when there is no conflict of schedules, can these establishments be called compatible?) Establishments may be proximate because of historical accident. T h e Yankee Stadium was placed in the lower Bronx to be as close as possible to the residents of other boroughs. T h e Bronx County Court House was located two blocks away because its site—on a wide street in a pleasant residential area, and adjacent to two parks —was one of the few remaining in the built-up sections of the borough that provided a suitable setting for a public building. It may be argued that the concept of linkage should encompass all establishments that have movement between them and that proximity is merely a secondary concomitant of the necessity for transporting persons and goods. If proximity, however, is not stipulated as part of the definition, then there is no clear distinction between linkage and some aspects of movement systems. Systems of movement are said to be functionally related to organized systems of business or social action. One of the major orders of personsmovement is composed of systems related to kind of establishment. A l l major systems of goods-movement are also related to establishments as bases or destinations—systems based on process of action, systems based on kind of trip, and systems based on kind of commodity. Linkage, however, may be considered a subsystem of movement in which the destination-and-origin establishments are specified and proximity between them is stipulated. This distinguishes linkage from movement systems which are defined as kinds of movement . . . without regard to concrete time or location. Linked establishments will be characterized by movements among each other, while the non-linked but proximate establishments will not. T h e analysis of linkages provides a clue to the relation between land uses and traffic (via systems of movement), and proximate establishments, both linked and non-linked, provide a

MOVEMENT

AND

LAND

USE

PATTERNS

basis f o r a n a l y z i n g the s t r u c t u r e of m o v e m e n t , that is, the totality of traffic at a p a r t i c u l a r place a n d time. An Illustration

of Land

Use

Pattern

I n a r e c e n t study of the c e n t r a l district of P h i l a d e l p h i a an a t t e m p t was m a d e to r e v e a l the m a n n e r in w h i c h land uses a r r a n g e d themselves i n the d o w n t o w n area of that city. P r i m a r y emphasis was p l a c e d u p o n t h e w a y i n w h i c h the activities a n d their associated m o v e m e n t r e q u i r e m e n t s i n f l u e n c e d the l o c a t i o n a l c h o i c e of various types of establishments. F o r d e s c r i p t i v e a n d a n a l y t i c a l purposes all n o n r e s i d e n t i a l establishments i n the area w e r e classified i n t o six basic l a n d use types: 1. Retailing: Every type of establishment selling goods primarily to the customer; and including department stores and specialty shops with city-wide appeal and convenience stores serving the resident or daytime populations of the central city. 2. Manufacturing: A l l establishments engaged in the production of fabricated goods and ranging all the way from loft manufacturing to large factories. 3. Wholesaling with stocks: A l l of the lines of wholesaling maintaining stocks on the premises and selling to the trade out of that stock. Display rooms and warehouses are the facilities generally required. 4. Wholesaling without stocks: A l l intermediaries handling sales transactions without maintaining stocks on the premises. W h i l e this category includes brokers and commission men it is much broader. In a number of lines of wholesaling such as coal and lumber it is customary for the wholesaler to take ownership but not physical possession of the merchandise. T h e usual requirement is for office space. 5. Business services: T h i s category covers many activities in which the customers are other establishments and in which services are sold rather than goods. Law firms, advertising agencies, real estate, banking, insurance, and engineering are among the sub-classes. Business services account for a large percentage of the demand for office space. 6. Consumer services: T h i s is the broadest of all the six categories as to type of facility although it covers only establishments providing services to the consumer. It ranges from repair shops and barber shops to museums and churches with a wide range of public, personal, and professional service in between. It will be seen that this category, broad as it is, has a definite place in the pattern of relationships among establishments. 11 11 Philadelphia

Central District

Study (Philadelphia, 1950), pp. 5-6.

1 16

MOVEMENT

AND LAND USE PATTERNS

In analyzing the distribution of establishments, an attempt was made to arrive at the delineation of functional areas by designating every block in terms of its principal activity. Functional type was defined in terms of the combinations of activities and their relative dominance block by block. If two types of establishments together accounted for 50 percent or more of the nonresidential floorspace in any block, the block was taken to be characterized by that combination. T h e six types of establishments can be arranged into fifteen different groups of two each, but the calculation revealed that only three of the combinations were sufficient to account for over 90 percent of the blocks in the central city. T h e combinations were: 1) manufacturing and wholesaling with stocks; 2) business services and wholesaling without stocks; 3) retailing and consumer services. These patterns, gross though they are, reveal the tendency for certain types of establishments to sort themselves into cohesive areas within the central district in accordance with the functions and activities that they perform in common. In this sorting process many locational factors come into play and the exigencies of the movement of persons and goods rank high among them. Both manufacturing and wholesaling with stocks are classes of activity that require large amounts of space for the storage and handling of goods. T h e y seek low-priced space generally found in the older buildings which tend to be concentrated in the older sections of the area. Within this group there is a major subdivision. T h e establishments that deal with the downtown department stores and other types of retail shops are found on the periphery of the concentrated portions of the retail shopping area, and those that supply markets outside the area tend to locate at truck and rail terminals and along the river fronts. There are not only positive factors that draw these two types of establishments together; there are also forces that repel other types of establishments. Noise, odors, and other unpleasant characteristics of establishments fabricating, storing, or assembling large quantities of goods are, of course, among them. But perhaps the most repellent is the fact that the movements of large quantities of goods interferes with other types of movements. Large trucks block the streets, and the movement of goods from the buildings to the trucks as well

MOVEMENT AND LAND USE PATTERNS

1 17

as the temporary storage of crates and cartons on the streets impedes the free movement of pedestrians along the sidewalk. The second type of functional area consists of establishments devoted to business services and wholesaling without stocks. Both of these types of establishments deal with business rather than with consumers and neither handles goods on the premises. Both typically require and can afford accessibility and prestige in location. Their space needs are primarily for office facilities. As a consequence, the concentration of these establishments is to be found in the vicinity of Broad and Market Streets (in the newer buildings) and around Independence Square where the insurance companies seek to associate themselves with the historical symbol of the area. Retailing and consumer services are the two groups of establishments that constitute the third type of functional area. These two types of activity are held together primarily by consumer traffic. While they usually are found together they are not usually in balanced proportions. Large retailing establishments, by drawing consumer traffic, create opportunity near by for specialty shops and small service establishments. Large service establishments, such as public or semipublic institutions, create opportunity in the immediate neighborhood for small retail stores. Thus the locations of establishments and the patterns of location are influenced by the functions and activities of establishments (the principal activity in particular) and the movements associated with the conduct of these activities. Viewing these movements in terms of the systems of which they are a part facilitates the analysis of establishments in terms of bases and destinations, their relationships to the spatial distribution of establishments with which they interact, and the tendency for certain types of establishments to seek proximate locations. Other factors such as the quality of space or rent levels have also been noted, and in the analysis of a real situation these cannot be omitted. In fact, in many individual instances these may be of equal or greater importance. In an integrated study of locational influences, however, it is possible to deal with seemingly disparate forces within a modification of the framework presented by Haig's concept of the friction of space. In the original statement of the concept, transportation

n 8

MOVEMENT AND LAND USE PATTERNS

costs and rent are presented as balancing forces. If the desire to raise the demand schedule is placed alongside the incentive to minimize transport costs, then many of the other locational influences can be treated within this intellectual structure. Prestige, for example, can be considered as a demand factor in which the establishment seeking a prestige location does so in an attempt to maintain or enlarge its clientele. Dynamic

Relationships

Up to this point the discussion has centered around the manner in which the need for movement influences the present location and spatial distribution of establishments-—the static situation. B u t since land use patterns are constantly changing, a comprehension of the forces which bring about changes is of importance. In fact, one of the principal reasons for examining a static situation is to derive some insight into its dynamics. T h e question now is this: How are changes in movement requirements related to changes in the pattern of land uses? In order for the pattern of land uses to change there must be a change in the spatial distribution of activities due to a rearrangement of establishments or to an alteration in their activities. Since the vacant tracts, parks, and streets are integral elements in the land use pattern, changes in these will also, by definition, vary the pattern of uses. T h u s , changes in the distribution of land uses may come about through processes that alter the activities of establishments at a given location, the character of improvements on the land, or the street system and other channels of movement. T h e forces that lead to changes in land use can be segregated into two broad groups. T h e distinction between these sets of forces is to be found in the terms "accommodation" and "accessibility." T h e first includes such factors as changing space requirements or rent-paying ability or other reasons that relate to the physical setting—the building space—in which an establishment is housed. Technological, administrative, or organizational change or economic vicissitudes may so alter the activities of an establishment that it is impelled to seek a different kind, amount, or quality of space from that which it presently occupies. T h i s category also in-

MOVEMENT

AND LAND USE PATTERNS

1 19

eludes fortuitous factors such as the necessity to seek new quarters because the building in which an establishment occupies space is slated for demolition or because a lease cannot be renewed. Factors related to accommodations as a force bringing about land use change, as well as questions centering around the ability to pay for more satisfactory quarters or locations are, of course, crucial considerations. But here they are accepted as given since it is not within the scope of the present study to probe into questions regarding the nature of change in space requirements of establishments, or the character of activities that can desire the highest economic return from the use of a site. T h e second set of factors, those related to accessibility, is concerned with the necessity for moving persons or goods. These relate to changes in land use through alterations in the nature of an establishment's relationship to others, or in the spatial distribution of establishments with which it regularly interacts. T h e desire to secure accessibility to a different set or distribution of establishments is the underlying force in this set of factors. Changing

Movement

Requirements

Since the functions and activities of an establishment give rise to certain types and patterns of movement, changes in the internal structure of establishments can be expected to alter its movement requirements. Changes in internal structure come about as a result of variations in technology and in business organization. A striking example of this is to be found in the recent changes that have occurred in some branches of wholesaling business. With standardization of items and purchase from catalogue or through specifications, a large section of the wholesaling business is conducted without stocks and no longer requires locations that are readily accessible to water, rail, or truck termini. Instead business is conducted by telephone or personal contact from offices in the center of town, a location most convenient to customers and sources of business contacts. In retailing, there has been a marked trend from corner grocer to large supermarket. This has served to increase the volume and type of goods shipped to retail food establishments of the latter

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type, and has extended the destination area for and number of trips to each of these shops. Sometimes sheer growth in size will bring about a change in associated movement by enabling an establishment to subdivide its constituent function and to move one of the constituents to a new and more propitious location. Many manufacturing plants have maintained a head office and salesroom in the downtown district but have moved their fabricating functions to the peripheral areas. Department stores have separated sales and display from warehousing and storage, locating the latter in areas suited for goods-movements. In each of these cases the separation of functions or activity has altered the nature of the movement associated with the downtown establishment by changing the goods-persons ratio, the pattern of home-to-work trips and the nature of necessary contacts with other establishments. The second way in which change in movement relates to changes in land use is to be found in external relationships among establishments. This includes the response to shifts in the location of establishments with which a given firm, agency or household interacts, as well as the effect of changes in social organization on the number and type devoted to specific types of activities. The various types of linkage and the compatibility of non-linked but proximate establishments provides an important tool in the analysis of the external factors in land use dynamics. Any change in the location of a dominant establishment will tend to be accompanied by changes in the location of the subordinate, ancillary, or satellite land uses. Non-linked uses that compete for space but have mutually harmonious relationships regarding goods- and personsmovements, can be expected to remain in proximity, other things being equal. Incompatible land uses, on the other hand, interfere with the operations of both establishments and provide incentive for one or the other to move to a more suitable location. Once a change has occurred, even if the incentive for a shift in land use comes from forces not related to movement, movement relationships and requirements will be altered. Through the interplay of forces, a change in land use caused by a factor unrelated to movement may create a situation in which movement relationships

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are released as dynamic factors. A n example may best illustrate how such a chain reaction may be brought about. T h e telephone and other long-distance methods of communication and control no longer make it necessary for the management of manufacturing firms to be located in the factory. T h e production units can be placed in an outlying area and the administrative offices located in office buildings in the central city at places convenient for the assembly of persons. Hence the tendency for offices to pile up in big buildings and concomitant generation of persons traffic. This in turn will drive out uses like wholesaling with stocks that are unable to operate satisfactorily in heavy mixed traffic. On the other hand, uses like small job printing, telephone, stationary and some types of consumer services will be attracted to the area. In this illustration the interrelationship between changes in land use and changes in movement is indicated by a chain of events. T h e nature of this interrelationship will become clearer when the major processes through which land use change comes about are analyzed. The Relocation of Firms or Households Perhaps the first process that comes to mind when land use change is discussed is shifting of firms or households from one location to another. A bank or insurance company will move its headquarters from an old to a new center, as will other types of nonresidential establishments. Perhaps the most mobile type of establishment, however, is the American household. Estimates in recent years indicate that, on the average, over one in five changes place of residence each year. Unfortunately, similar estimates are not available for nonresidential establishments, but one may venture that the rate is considerably lower. T h e principal reasons why a firm or household may be attracted to a new location have already been indicated in large part (changes in movement requirements due to internal shifts in activities and external shifts in the location of establishments); but there are additional reasons for the relocation of establishments. For example, the existence of uses in the immediate area that impede the ready movement of goods or persons will operate as a factor to repel

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AND LAND USE PATTERNS

a given use from its present location. Changes in the street system or in other channels of movement may cause an establishment to change location. This factor is treated in some detail under a subsequent heading. Changes in the Activities Given

of Establishments

at a

Location

T h e second process by which land use change comes about is through changes that occur internally in an establishment that remains located at a given site. Retail stores, for example, have responded to a shift in the composition of traffic passing the establishments: Men's clothing stores located along the paths of people traveling to and from work have taken in lines of women's wear in recent years to capitalize on the increase in the number and proportion of women on home-to-work trips. Department stores have introduced grocery and other types of food departments on their street floors. Another type of internal change that results from a change in movement requirements is the subdivision of functions and the removal of one or more to other locations more suited to their movement requirements. T h e relocation of a constituent function or activity may come about because uses are incompatible or because the pattern of linkage changes. T h u s what might have been a manufacturing area at one time may now be an administrative district occupied by the main offices of manufacturing firms. Differential Aggregate

Growth Rates and Changes

in

Activities

A change in the land use composition of an area may come about because of differential rates of growth among establishments of various types, either in an urban area as a whole or in certain subareas within a city. This results in changes in relative proportion of establishments devoted to various activities. It is considered by some to be a more significant long-run process of change than the shifting of firms or households from one location to another. 12 12 T h e same observation has been made in regard to the shift in the locational distribution of industrial plants for the nation. From the experience of the years 1928

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123

T h e trend toward services and distribution activities has been observed repeatedly in studies of the entire national economy. 1 3 In the U n i t e d States, as in other advanced industrial countries, the p r o p o r t i o n of the labor force e m p l o y e d in agriculture has declined, the percentage in trade, finance, g o v e r n m e n t , and service occupations increased, and the r e m a i n i n g groups have changed little in their total share of the labor force. T h e same tendencies are to be seen in the distribution of national i n c o m e and aggregate payments by industry. A t the same time, it has b e e n universally recognized that the p o p u l a t i o n of the U n i t e d States has steadily b e c o m e m o r e urbanized. B u t w h a t may n o t have b e e n so evident is that the balance of activities w i t h i n the range of u r b a n life has been shifting steadily away f r o m p r o d u c t i o n toward distribution and services, a n d that this shift has had f o r m a t i v e influence o n the land use patterns in u r b a n areas. T h e structural change in the activities of the central district of Philadelphia, for example, is revealed by an i n d e x of the rate of net g r o w t h of the n u m b e r of establishments of various types. 14 F o r all types of establishments c o m b i n e d , the ratio b e t w e e n the total n u m b e r of establishments in 1906 and the n u m b e r in 1949 is equivalent to an i n d e x of 1.35. Variations f r o m this average indicate the extent to w h i c h various types of activities have shifted their relative importance in the i n t e r v e n i n g forty-three years. T h e

following

table indicates the indexes for five m a j o r types of establishments: Construction Manufacturing Retailing

.83 1.1a 1.16

Wholesaling Business services Consumer services

1.24 1.45 1.58

Because of lack of detail in the early records it was impossible to segregate wholesaling establishments h a n d l i n g stock f r o m those to 1933, it was concluded that "a very small fraction of industry has moved it location during this period." Carter Goodrich et al., Migration and Economic Opportunity (Philadelphia, 1936), p. 340. See also E. M. Hoover, Location of Economic Activity, chap. 9, " T h e Process of Locational Change," pp. 145-65. Hoover similarly maintains (p. 150) that "most shifts in the location of any specific industry are essentiallygeographic differentials in the rate of growth of the industry with the actual relocation of firms or plants playing a minor role." is See, for example, John D. Durant, The Labor Force in the United States, 18901960 (New York, 1948); and Simon Kuznets, National Income, A Summary of Findings (New York, 1946), Tables 11 and 12. 14 Philadelphia Central District Study, pp. 60, 101.

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which held title but not physical possession of goods. Data for a later period indicate the varying tendencies between these two types of establishments. Between 1934 and 1949 the goods-handling wholesaling establishments increased from 2,040 to 2,120, or 4 percent, while the nongoods-handling wholesaling establishments increased from 1,351 to 2,570, or 90 percent, during the same period of time. T h e change in these proportions is, of course, reflected in a shift in the composition of land use, and therefore is a change in pattern simply on the basis of a changed amount of land or building space devoted to each kind of establishment in aggregate. But in addition to the aggregative effects, the different types of establishments that lie behind the shift in proportions give additional impetus to changes in land use patterns. T h e demise of an establishment at one location and the birth of another at a different location may make for change in the pattern of land uses even if the new and deceased establishments were of the same types. But if these two are of different types, then the effect of the changing establishment m i x on the spatial distribution of land uses is accentuated. A n illustration of the manner in which land use change comes about as a result of growth and attrition in the number of establishments is provided by the Philadelphia Central District Study. 15 A historical study of the survival rates among nonresidential establishments over the period 1906-1949 was made for a sample of thirtynine blocks located in the central district. Data were derived by listing according to type of activity all establishments that were located in the sample blocks in the year 1930 and then tracing the change backward to 1906 and forward to 1949. In 1930 there were 5,038 establishments in the thirty-nine blocks studied, representing a large proportion of all establishments in the central business district. Of these, only 1,143, or 23 percent, were located anywhere in the central district in 1906, and only 1,542, or 31 percent, still existed in the central district in 1949. These data provide a striking is Data for this section were drawn from Philadelphia Central District Study, pp. 58-61; First Phase of the Philadelphia Central District Study, pp. 7-43 to 7-45 and from the two maps of CPC Block 18-102 (no page number); and Number of Central District Establishments in Each Block by Kind of Business, 1949; Supplementary Tables, Vol. 3.

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indication of the very large turnover of business establishments in the core area of a large city. T h e influence of the turnover of establishments on a small area is revealed by the land use composition of standard Philadelphia Planning Commission Block # i S - i o E for bench-mark dates of 1906, 1930, and 1949. T h e block is characterized by two principal functions, business services (predominantly insurance), and wholesaling. For the years of record the proportion of business service establishments to total establishments consistently declined from 68 to 58 to 32 percent, while wholesaling rose from 14 to 24 to 33 percent of total. T h e records further reveal that of 376 establishments in the block in 1930, 236 did not exist in 1906 and of these, 129 (55 percent) were business services and 64 (27 percent) were wholesaling. T h e distribution of the new firms tended to shift the balance in favor of wholesaling. Between 1930 and 1949, it was attrition rather than growth that accentuated the change in the established direction. In this nineteen-year period the number of establishments located in the survey block declined from 376 to 121. But of the 121 establishments in the block in 1949 only 11 had been in existence in 1930 and 110 were new establishments. T h e composition of the new establishments again was such as to shift the proportion in favor of wholesaling. It is interesting to observe the general spatial distribution of establishments over this period. Most of the enterprises which had moved to the survey block between 1906 and 1930 (and were still there in 1930) had come from a two-block radius, indicating little geographic movement of the focus of business services and wholesaling. By 1949 a shift in the location of the functional area was evident. Of the 108 enterprises which were in the survey block in 1930 and had moved to other locations in the central business district, 61 (56 percent) remained within a two-block radius of their original location while the remainder (44 percent) tended to cluster in a new and established concentration twelve to fourteen blocks away. It is thus suggested that a major process of land use change is to be found in the location of new establishments which reshape existing concentrations. T h e new establishments usually perform new types

MOVEMENT AND LAND USE PATTERNS of functions or variants of the functions of existing establishments. Moreover, a new establishment has the opportunity to choose a location most suitable for its purposes and, unlike an existing firm, is unfettered by the cost of moving, disruption of business, inertia, or the loss of goodwill associated with an established location. T h e effect of the birth and death of firms will also be magnified by the sharply varying space requirements of the existing and remaining firms. In the land use shifts resulting from the birth and death of establishments the role of movement is readily seen. Business firms may die for any of a host of reasons, one of which may be wrong location. For goods-handling firms, transportation costs may have been too heavy because channels of movement were inadequate or proximate uses were antagonistic. Retail shops or other types of establishments dependent upon visits from members of the general public may find that their location is inconvenient to the clientele they expected to attract or that persons who were "customers" in the past have moved to other areas. A new establishment has the advantage of being able to choose a location most propitious to its movement requirements, within the limitations of the rent level and the availability of existing space. But by the same token, since it has not as yet commenced operation, it cannot be certain that the interactions it expects with a group of predesignated establishments will materialize in the form anticipated. T h e original location is thus based upon estimates that contain a good measure of guesswork. T h e degree of uncertainty is diminished if an establishment is not the first of its type to locate in an area, for then it can make judgment on the basis of the experience of others. T h e shifts in the aggregate composition of land uses resulting from differential growth rates can be assessed only in part in terms of movement of goods and persons. T h e drift from the production of goods to the production of services is a national phenomenon that accompanies a rising standard of living. Within urban areas, the high cost of transporting goods through the congested city streets encourages the trend from goods-handling to persons-handling establishments, as it did in the central district of Philadelphia. If the

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127

c h a n g i n g m o v e m e n t pattern has n o t b e e n a cause it has surely b e e n a consequence of the altered character of u r b a n activities. Variations over time in the kinds of activities that are c o n d u c t e d in cities are extremely significant factors in the relationship b e t w e e n m o v e m e n t and land use dynamics. Changes in activities and in the establishments p e r f o r m i n g them alter systems of action and their corresponding m o v e m e n t systems. A m a j o r consequence is manifest in the r e a l i g n m e n t of establishments that constitute the bases a n d destinations of various m o v e m e n t systems. A n o t h e r c o n c o m i t a n t is a change in the daily rhythms of m o v e m e n t . T h e d r i f t f r o m goods- to persons-handling establishments brings a b o u t shifts f r o m goods- to persons-movement systems, and influences the pattern of daily variations in the v o l u m e of personsm o v e m e n t . W o r k e r s e m p l o y e d in goods-handling firms, for example, are usually r e q u i r e d to report earlier or leave later than the 9 A.M. to 5 P.M. employees of establishments d e a l i n g w i t h persons. Goods-handling establishments f r e q u e n t l y w o r k m o r e than one shift. T h u s the trend f r o m goods to persons activities will cause m o r e home-to-work trips to be concentrated d u r i n g the peak hours of travel or to coincide with trips for other purposes. E v e n w i t h o u t an increase in the total daily v o l u m e of traffic, congestion may b e aggravated at crucial periods of the day. Changes in the Available Supply of Space O n e of the most dramatic and readily observable factors in land use change is to be f o u n d in the construction of new buildings. A s a rule, the new structure is p u t to a different use than the structures that previously occupied the site. Occasionally the general category of use is the same, b u t there are differences in quality; for instance, a m o d e r n apartment b u i l d i n g replaces several ancient single-family structures. If the b u i l d i n g has been constructed o n vacant land then the n a t u r e of the change is obvious. A l t h o u g h new construction is the most evident means of increasi n g the total a m o u n t of b u i l d i n g space, 10 the space devoted to a In housing, for example, there are no years in which demolitions exceeded the volume of new dwelling units. A l t h o u g h there are no similar records for nonresidential structures, the same appears to be true.

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particular type of use may be increased within the limits of the existing supply. Many an old private residence now houses offices or stores, as a walk through the central district of any city will reveal. T h e construction of new buildings, however, is a condition rather than a process of change. Additional space either at existing concentrations or at new locations serves to facilitate the working out of other forces in process. It does this by making available additional physical accommodations both for enterprises that wish to move from their present locations and for new establishments. A new structure may provide a more strategic location for existing firms and for the estimated movement requirements of new establishments. If the structure has been built for the expressed occupancy of a stipulated establishment then its choice of location was in large measure governed by its movement requirements, expressed in terms discussed previously. W h e n establishments are attracted to new buildings because of the quality of space or the prestige associated with the occupancy of modern structures, they may form new foci of activities previously located elsewhere. Establishments that are either directly linked or linked in ancillary or satellite fashion will be attracted to the new concentrations. In fact, buildings frequently make provisions for this by constructing suitable facilities for the linked uses—witness the shops at any large rail or bus terminal or the doctors' offices on the ground floors of large apartment houses. Change in the available amount and type of building space is also brought about by direct governmental action in the fields of slum clearance and urban redevelopment. T h e motives for these programs are only indirectly related to movement. T h e i r primary purpose is to make decent, safe, and sanitary dwellings available at low rent to families in the lower ranges of the income distribution or to make strategically located land available for private reuse at a value in consonance with the new use. However, before any local redevelopment proposal can become eligible for federal grant or loan under T i t l e I of the Housing A c t of 1949, the local public agency must certify that it is in accordance with a master plan, which presumably has a section dealing with problems of movement, circulation, and transportation.

M O V E M E N T AND LAND USE PATTERNS

129

Although the bulk o£ local redevelopment programs focus on reuse of land by establishments, a few center their consideration on the street system and other movement channels. In Mobile, Alabama, for example, a proposed redevelopment site is directly in the path of the shortest connection between two major throughfares leading from a residential district to the industrial and dock sections." As the site is now laid out, traffic from the residential areas must weave through a tangle of narrow streets to reach the industrial areas. T h e Broad-Beauregard Streets project has as its major purpose the provision of a wide connecting street, which is expected to remove the present traffic bottleneck. Many other redevelopment proposals also provide for revision in the street system, but for the most part these are incidental to other objectives. Changes in the Street System and Other

Movement

Channels

T h e street system is, of course, a basic element in the land use pattern of a city. In many urban areas, the proportion of land occupied by streets exceeds any other use. O n the average, one third of the developed area of a city is devoted to streets. Street area amounts to 72 percent as much as the combined area occupied by private residential, commercial, and industrial building. 18 T h e importance of the street system, however, is not due to the volume of land that it occupies. T h e street system constitutes the framework of a city. T h e size, shape, and orientation of blocks, lots, and in some cases, of buildings are determined to a considerable degree by the street pattern. It exerts an influence on the pattern of land uses by establishing the basic avenues of accessibility. Streets not only provide for the movement of persons and the transportation of commodities, they also furnish light, air, and means of access to abutting property. Below the surface of streets are found most of the city's utility installations—telephone and telegraph cables, the distribution systems for electricity, gas, water, and heat, and facilities for the disposition of drainage water and sewage. IT A Preliminary Report on Urban Redevelopment for Mobile, Alabama (Mobile, n.d.), p. 7. is Harland Bartholomew, Urban Land Uses (Cambridge, Mass., 1932), Table 40, p. 105.

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T h e streets in the central business district of many American cities show little alteration from, and in fact may be identical with, those that served the area during a less populous and more leisurely time. Many of the early street systems were platted, but others just developed in random and casual fashion. This situation is aggravated by the fact that many cities have developed their entire street pattern by the mechanical extension of the original plat. Even the designed street systems, perhaps efficient in their day, have outlived their original purpose. T h e great number of crosstown streets on Manhattan Island at one time served the river to river traffic, while persons and goods were carried to the upper sections of the island by boat. T h e few north-south streets now carry the burden of traffic, and the narrow cross streets are inadequate as feeders, difficult for passage, and inefficient for access. T h e streets of a city appear to be one of the most permanent elements in the entire man-made physical structure. Once utilities are installed and the abutting lots improved, street widening or relocation is exceedingly difficult and very costly. T h e rebuilding of an entire street system, even for a small city, is virtually unthinkable. Changes in streets and the street system occur nevertheless, for the most part within the framework of the existing street pattern. Streets are widened or extended, or their use regulated. Less frequently some are closed or others opened. Only rarely are there drastic changes. These usually take the form of the provision of a new type of street—a circumferential highway or a parkway. Most of the important changes occur in other channels of movement—the addition of a subway system or an elevated route, the institution of a trolley or bus line. How do changes in channels of movement come about and how are the antecedents of change related to movement? It is, of course, quite obvious that changing movement requirements are the direct long-run cause for changes in the street system and in some of the other channels of movement. Changing movement requirements can be viewed in two ways, first in terms of variations in the volume of movement, and second in terms of variations in the kind of movement. Change in the volume of movement may result from city growth

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131

even in the absence of change in basic urban structure. Thus, the more intensive use of land brought about by the construction of a greater amount of building space per unit of land, or by more intensive occupancy of a given amount of space, will in and of itself generate an increase in the volume of movement. Changes of this order increase the total burden of traffic on the channels that serve the areas of intensive use and bring pressure to increase their capacity either by traffic management, street widening, or the provision of additional surface, subsurface, or overhead channels. Changes in the kind of movement on a particular channel occur as a result of shifts in the land use pattern. Goods-handling establishments in an area may give way to establishments dealing primarily with persons, or the reverse may happen, making for the necessity to adapt the streets or other channels to different traffic requirements. City growth may be extensive as well as intensive, with new urban developments forming on the outskirts of the builtup areas. In the transformation of vacant to occupied land or rural to urban uses, it is usually necessary to tie the new developments to existing concentrations with roads, bus lines, commuting trains. Perhaps the most significant influence on movement channels is the change in movement requirements brought about by technological advances in modes of transportation. T h e introduction and widespread use of the private automobile has been the greatest single factor in altering the functional requirements of the street system. T h e use of motor truck for commodities transport has liberated large goods-handling establishments from the rail siding and the dock, but it has created the need in other areas for special streets adapted to heavy truck traffic. Just as changes in kind or intensity of land use by establishments bring pressure for changes in the channels of movement, changes in channels tend to affect the distribution of establishments by altering existing paths of movement and avenues of accessibility. Even minor changes, such as traffic regulations which establish one-way streets or shift bus stops will have some influence on land use, particularly in regard to retail shops. Changes in channels can reduce accessibility as well as increase it. Congestion in a channel may render a street that was previously satisfactory inadequate for current

1^2

MOVEMENT AND LAND USE PATTERNS

movement requirements. These changing patterns of accessibility generate attempts on the part of establishments to locate more conveniently in relation to others with which they interact. Growth patterns are also influenced. The construction of a new road or the extension of a bus or subway line will lead to further development of outlying areas, particularly those directly accessible to the new channel. The interpénétration of influences is of particular importance to the traffic engineer and the city planner. T h e existing distribution of establishments of itself is not a sufficient basis for developing a program of streets or highways or subway construction. Nor can a projected distribution of establishments based upon the extension of existing trends suffice. The design of any new facility must take into account the land use changes that the additional or altered channel can be expected to bring about (as well as the additional traffic that the new facility will generate). Thus the design of a new channel or the redesigning of an existing channel of movement should be a process of iteration, in which the proposed facility, the existing land use pattern and its anticipated changes are brought into consonance. Summary T h e processes by which various land uses sort themselves out in the urban pattern are in large measure a function of the movement requirements of establishments. Specialization of urban activities makes it necessary for establishments and their members to communicate with each other, and consequently there is a pervasive tendency for establishments to make accessibility a major locational consideration. The pattern of land uses is thus a large dependent system in which choice of location of an establishment is made in terms of spatial distribution of others with which it interacts. For some this means access to the largest number of persons, firms, or households—a central location; for others it means convenience in regard to an inexpensive channel of goods-movement; and in still other cases it means actual proximity. The tendency for certain kinds of establishments to seek proximity is described by the concept of linkage which aids in understanding the clustering of like

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133

and unlike establishments that characterize land use patterns. The concept of linkage also enables the translation of systems of social and economic action into ecological terms. Shifts in locational pattern may come about as a result of changes in the movement requirements that are due to alterations in the internal activities of an establishment, to response of an establishment to shifts in the locations of others with which it is linked, or to differential rates of growth among establishments of various types. Changes in the movement requirements of an establishment or area will operate as a force to alter existing channels of movement. This relationship between the locational distribution of establishments and movement channels is reciprocal in character. A changing land use pattern will generate the need for additional physical channels of movement and new or changed traffic facilities will in turn encourage change in the existing distribution of establishments. This interpénétration of influences is significant in the attempts to rationalize the movement structure of an urban area. With further understanding it may also provide a basis for employing traffic channels as an instrument to secure a more efficient distribution of urban land use.

CHAPTER

v i n Relating Movement of

Persons and Goods to Land Use: Selected Explorations this study has been an exploration through a relatively uncharted field. Relationships between land use and the movement of persons, goods, and vehicles have been probed and concepts formulated. It is hoped that these concepts will provide a basis for a new analytical framework for the investigation of traffic and land use, and eventually contribute to the forging of new and more powerful tools that the planner may use in the direction and guidance of the physical structure of urban areas. I N ESSENCE,

T h e study has also encompassed the investigation, development, and testing of techniques and procedures for securing data. This has included a survey and appraisal of existing methods of traffic analysis as well as the investigation of new measures and methods. In the process of exploring the field many important gaps in knowledge were encountered, and as a result, suggestions for further study in limited segments of the problem have been presented. This chapter is devoted to a summary of existing traffic analysis methods, the presentation of some new measures of traffic and movement, and some of the more significant suggestions for further research. A statement of the methods and procedures used in field investigations appears in Appendix A. In terms of the framework of study presented in this report, the appropriate specific data for research in this field would measure and describe characteristics of the following: moving persons, the movement of persons, moving goods, the movement of goods, moving vehicles, the movement of vehicles, and the establishments among which movement occurs. In addition, of course, other in-

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135

formation is needed for background in any particular study undertaken on such subjects as land use patterns, the economic and social characteristics of an urban area, and characteristics of movement channels—highways, transit lines, and vehicles. Traffic Analysis

Methods

Traditionally, traffic analyses have been concerned chiefly with vehicles and their movement. Vehicles have been counted in motion and parked. Drivers have been interviewed at cordon lines, at individual highway points, and at parking places. Vehicle movements have been observed and summarized on traffic flow maps. ORIGIN A N D D E S T I N A T I O N

SURVEYS

Vehicle movement has been the major focus also in studies of traffic origin and destination. At first, such data were secured by interviewing drivers at a cordon line such as the boundaries of a central district or other urban area under study. This technique is still used, and is combined with the home interview method developed by the United States Bureau of Public Roads with the cooperation of a number of state highway departments. T h e combined internal and external O & D survey is by this time a fairly standard technique which has been employed in a variety of urban areas with populations ranging from 12,500 to over two and a half million. 1 DATA

ON

PERSONS-MOVEMENT

Information on moving persons gathered in O 8c D surveys includes age, sex, occupation, and industry (for all individuals over five years of age in each household interviewed, except those on pedestrian trips, which are not included). Persons making trips either as vehicle drivers or as passengers are included. On the movement of persons the data may show mode of travel, place of residence, place of origin and destination, purpose of trip, day of week, and time of departure and arrival. Route or frequency of travel are 1 For a detailed discussion o£ the O & D surveys and their significance for various levels of traffic analysis, see Chapter I, pp. 7-10. A n explanation of the desire line and contour methods of presenting O 8c D data graphically is given on p. 30.

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not included for either goods or persons. As in the case of goodsmovement, the nature of establishment at origin or destination of persons-movement is not given, nor are the locations of destinations other than those called "primary." Origin-and-destination data on persons-movement are procured by interview either at a cordon line or in places of residence. DATA ON

GOODS-MOVEMENT

T h e most developed form of the O & D survey does procure data other than that on moving vehicles. Data on goods-movement includes information on the commodities carried in trucks as well as the locations of their origins and destinations, but not on nature of establishments at origins or destinations, or the industries or businesses (or processes of action) for which the transfers are made. PARKING STUDIES

In more or less standardized parking surveys,2 data procured by interview at parking locations similarly include information on location of destination and purpose of trip; but again they generally do not include more than one destination, and for that do not indicate the nature of the establishment visited. Moreover, parking data about destination and purpose are generally taken for auto drivers only. Passengers, whose trips may be more important in determining parking location than those of drivers in some instances, are not interviewed. It is in the analyses of parking requirements, however, that the principal attempts to relate traffic to land use are found. In one of the most significant of these studies, Thompson and Stegmaier experiment with a method of using O & D data to analyze the "power of buildings of various types to attract traffic and create parking demand." 3 T h e number of persons who drove passenger 2 A number of reports of parking studies explain the techniques used. See, for example, Bureau of Public Roads, U.S. Department of Commerce, Parking Study Manual (Washington, D.C., 1949); Oregon State Highway, 1946—Portland Metropolitan Area Traffic Survey Parking Study Report, Technical Report No. 49-3 (Salem, 1949); Rhode Island Department of Public Works, A Parking Survey of the Providence Central Business District, 1945 (Providence, 1946); State of Washington Department of Highways, A Parking Study of the Central Business District (Seattle, 1947). 3 J. Trueman Thompson and Joseph T . Stegmaier, " T h e Effect of Building Space Usage on Traffic Generation and Parking Demand," in Proceedings of the Highway Research Board, XXVIII (1949), 320.

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137

automobiles to destinations in each o£ fifteen buildings and one shopping center were calculated from O & D data for Baltimore. On the assumption that each auto driver represented a potential parker and taking into consideration additional information on purpose of trip and average parking time, the parking requirements were calculated and expressed as ratios of a measure deemed most appropriate for each of the buildings. An interesting study of parking demand which utilized a concept similar to assembly area was undertaken by Pratt, in Bridgeport.4 In estimating the parking requirements of the customers of the major department store in that city, Pratt took account of the fact that visitors to the store were likely to have additional destinations in the downtown area. Because of a high proportion of individuals with "multiple destinations," it was difficult to assign the parking requirements of this group to any one establishment or building. He met this problem by administering a questionnaire to a sample of customers visiting the department store on an average day, collecting data on time of arrival in the downtown area, mode of travel, shopping destinations prior to entering the store and intended destinations after departure from the store. Utilizing this information, Pratt derived estimates of the need for parking space attributable to the department store alone. The estimates, however, are limited to the parking requirements of shoppers, and do not consider the amount of parking space required by the employees and executives of the store, nor the non-shopping visitors. The analysis of multiple destinations and the use of questionnaire techniques at a nonresidential establishment, are the significant contributions of this study. Journey-to-Work and Daytime-Population Studies Studies of travel between home and work and of the daytime population of central urban areas employ a large variety of different data sources and methods of data collection. Kate K. Liepmann, 8 for example, classifies previous journey-to-work studies and surveys into three general types: 1) official censuses taken in several Euro* Charles O. Pratt, " T h e Department Store and Parking," Traffic Quarterly, January, 1952, p. 116. 5 Kate K. Liepmann, The Journey to Work: Its Significance for Industrial and Community Life (New York, 1944).

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pean countries which included place of work as well as place of residence; 2) studies of the official records of railway and other transportation companies; 3) studies based upon data drawn from the personnel records of industrial establishments. Each of these types of studies, Liepmann maintains, allows only a partial view of the entire problem: Data provided by a Census reveal the demographic conditions relevant to the daily movements, but fail to throw light on the journey. Transport statistics, on the contrary, usually yield no further information than a few data on the journey; in one exceptional case only, railway records furnished the material for a comprehensive investigation. Monographs which are based on the personnel records of individual firms provide evidence of the effects of daily traveling on the workers' health and efficiency but neglect the demographic aspects.6 Liepmann attempts to overcome some of the major limitations inherent in the segmental studies by examining the journey to work from two complementary points of view: "conflux at the workplace," and "dispersion from the place of residence." T h e study of workers at their places of employment was undertaken for thirty-six firms which were members of the Industrial Welfare Society and six large firms located in London, Birmingham, and Oxford. Data were collected on distribution of the place of residence, age, and sex of workers traveling, time and distance of work trip, fares and cost of travel, and effect on health. T o study workers at their places of residence, Liepmann drew on the records collected in two largescale existing surveys: the New Survey of London Life and Labor, 1929-1930; and the London County Council survey of the journeys to work made by residents of the London County Council housing estates. Here the emphasis was placed on the number of workers in the household, the length of the work trip, variations in worktrip patterns within households that had more than one worker, and the importance of travel to work fares in the budget of a worker's family. In the body of the monograph these data, implemented by an extensive variety of collateral sources, are analyzed and discussed. While the journey-to-work studies focus on places of employment 6

Ibid., p. 111.

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139

or residence, studies of daytime p o p u l a t i o n investigate the daily a c c u m u l a t i o n of persons w i t h various purposes in a m a j o r area of assembly. T h e most n o t a b l e and detailed study was prepared by Breese w h o estimated and described the daytime p o p u l a t i o n of the C h i c a g o central business district in 1940, and the trends f r o m 1926 t h r o u g h 1946, p a y i n g particular attention to the factor of transportation. 7 T h e central business district was studied in terms of the region it serves, the f u n c t i o n it performs, the size and place of o r i g i n of the p o p u l a t i o n w h i c h visits it b e t w e e n the hours of 7 A.M. and 7 P.M., a n d the m o d e of transportation used. T h e distrib u t i o n of daytime p o p u l a t i o n w i t h i n the district is related to patterns of land use (classified into broad categories of b u i l d i n g type), land values (assessments), and the facilities of the transportation system serving the district. F o r this purpose the daytime p o p u l a t i o n was d i v i d e d into three m a j o r groups: emp'oyees, p e r m a n e n t residents and hotel guests, and " p e d e s t r i a n s " — a s s u m e d to consist primarily of shoppers. A m a j o r c o n t r i b u t i o n of Breese's w o r k lies in the c o m p i l a t i o n and organization of a tremendous mass of statistical data f r o m a w i d e variety of sources. As such, it provides a m i n e of i n f o r m a t i o n that can be used for the analysis of areas in w h i c h large masses of persons congregate f o r a variety of purposes. Studies

of

Persons-Movement

A t the b e g i n n i n g of our research it was believed that a study of the m o v e m e n t of people and goods associated w i t h land use w o u l d r e q u i r e some data not i n c l u d e d in customary traffic surveys. Furthermore, it seemed likely that some kinds of data c o u l d best be o b t a i n e d at establishments w h i c h served as individuals' nonresidential bases and as destinations. Finally, it was assumed that data o n goods-movement collected at nonresidential establishments w o u l d be needed to s u p p l e m e n t those available f r o m O & D surveys or other surveys w h i c h were focussed on truck m o v e m e n t . In the p l a n n i n g of field work intended primarily to test methods of data collection, account was taken not only of customary tech1 Gerald W . Breese, The Daytime Chicago (Chicago, 1949).

Population

of the Central Business

District

of

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EXPLORATIONS

niques for home-interview origin-and-destination surveys, but also of methods and techniques developed in traffic studies in Fort Wayne, Philadelphia, and Cedar Rapids. 8 Since it was believed that considerable experience had been developed in collecting data at residential establishments through home interviews and other methods, we decided to concentrate the limited resources available for this project on experimental studies at nonresidential establishments. T H E FORT W A Y N E STUDY

T h e first of the traffic studies mentioned above was conducted in Fort Wayne and its environs within Allen County, Indiana, by the Traffic Audit Bureau, Inc. during 1945-1946." T h e major purpose of the study was to discover the extent to which individuals traveling about the city were "exposed" to outdoor advertising displays at various locations. One phase of the project was devoted to a home-interview survey intended to discover patterns of outdoor travel for residents of Allen County. Within a selected sample, consisting of 1,300 homes in Allen County, all persons fourteen years of age or over were questioned concerning all travel made the previous day from home to some destination and back home again. Over 3,300 persons were interviewed. Information about the people traveling included data on age, sex, employment status, and grade in school. Each dwelling was classified in some detail by location, by average rental of residence in the block, and by race of occupant. Additional information indicated whether or not the family had a telephone and one or more automobiles. A trip was taken to mean all travel from the time a person left home until he returned home. For each trip, information was obtained on date, day of week, time period of start and end, primary destination by enumeration district, and purpose. In addition, the exact route followed on each trip, mode of travel used, and direction of travel were recorded. In order to tabulate route information, "checking points" were s Some of the research findings of these studies have been presented and discussed in Chapter V. » Traffic Audit Bureau, Methods for the Evaluation of Outdoor Advertising (New York, 1947).

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EXPLORATIONS

141

plotted on street maps of the city and road maps of the county. There were 1,527 checking points in the county, of which 146 were in the central business district and 364 were outside the city limits. Each checking point represented a distance of one block within the central business district, about two blocks on the average within the city outside the central business district, and about three eighths of a mile on the average outside the city limits. Each trip was traced on a map and each time a trip passed a checking point a card was punched to identify the checking point, the mode of travel used, the direction in which the individual was traveling and all of the relevant data about the individual traveling. In addition to the home interviews, traffic counts were taken at various points and automobile license numbers were checked over a period of time in an effort to determine the general areas from which people had come and the frequency with which they passed the various check points. A STUDY

OF THE PHILADELPHIA

DISPERSION

MARKET

In 1948, Reavis Cox conducted an exploratory study of the Philadelphia dispersion market with the objective of developing measures and indexes of market efficiency.10 T h e study emphasized construction of hypotheses, possible sources of data, and methods for data collection. It was assumed that the efficiency of operation of a dispersion market is, in part, a function of the amount of effort required from all who participate in marketing activities, including consumers. Consequently, a section of the study was devoted to experimentation with the collection of data from households on all their marketing activity over a period of time, including the travel of individuals. It was assumed that the locus of a consumer in relation to marketing outlets was not only his place of residence, but 10 In the planning and execution of the field work and resulting analysis on this section of the project, Reavis Cox, Professor of Marketing in the University of Pennsylvania, enlisted the participation of Alderson and Sessions of Philadelphia. T h i s description of the technique employed is condensed from an unpublished report dated December 31, 1948, entitled, "Experimental Study in Survey Techniques: A n Analysis of the Philadelphia Dispersion Market" for the Wharton School of Commerce and Finance, University of Pennsylvania, submitted by Alderson and Sessions, Inc., in Philadelphia. T h i s material has been included in the present report with the kind permission of Messrs. Cox and Alderson.

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also included places on his orbit of travel about the city during a day's activity. Accordingly, various means of obtaining this information were attempted, including a general interview survey. W h e n it developed that the interview survey could not be relied upon to indicate travel accurately over any extended period of time and that the person at home who happened to be interviewed could not adequately describe travel patterns of other members of the household, the interview method was abandoned and experiments were made with a panel method. A small group of households in each of three areas of Philadelphia agreed to keep travel diaries for each member of the household for standard periods of time varying from one to five weeks. Diaries were kept on forms provided, with space to enter day and date; time the individual left home; the means of travel (walking included); the destination or destinations, including kind of establishment and location; the time of arrival at each destination; the time the individual left each destination; the means of travel and the time the individual returned home. Another form used for maintaining daily travel records included the name of the individual, address, date of trip, and day of week. For each trip segment the following information was entered: mode of travel, direction, route (name of street or streets), destination (name of street or address), stops made, location and purpose, time arrived, time left, and expenditures made. T h e second form thus secured data on actual routes followed. If travel diaries were checked by field workers frequently and if each household were paid a small amount to keep the records, it was found that acceptable data could be procured and a large proportion of the households would be willing to participate. A few of the families, however, dropped out before the designated time, a circumstance which would have disturbed a scientifically designed sample. I n this Philadelphia project, however, no attempt was made to procure significant data on a sampling basis, the emphasis being placed on experimentation with techniques. Because of the small number of households in the survey, no great difficulty was encountered in tabulation or analysis of the data procured. For a number of households, travel patterns of individuals were

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143

mapped and some very interesting differences in travel habits were observed. During and following the panel period, participants were called together in "clinic" meetings where the techniques were discussed and the validity of the data was appraised. T H E C E D A R RAPIDS

STUDY

Following the development of the panel method for recording travel information in Philadelphia, the Traffic Audit Bureau enlisted the cooperation of Alderson and Sessions for a survey in Linn County, Iowa, which includes the city of Cedar Rapids. 11 Again the major purpose was to measure the exposure of the traveling public to outdoor advertising displays. A deficiency of the Fort Wayne study previously noted by the Traffic Audit Bureau was that coverage and rate of repetition had been measured for only one day's travel. T A B then sought to investigate the amount of repetition of travel of various kinds and at various locations over a thirty-day period. "This meant the measurement of population movements in terms of (a) the separate individuals who comprised the traffic streams passing an average showing." 12 As in the Philadelphia study, travel diaries were used and individuals were compensated for keeping them. A random sample of slightly over one percent of the families in the county, consisting of over six hundred persons, was selected. Three quarters of the persons in the sample lived within Cedar Rapids. No family was included in the analysis unless records were secured for all members ten years of age and over for the full thirty days. It is reported, however, that a high percentage of those approached consented to participate and completed the month's assignment—possibly a higher percentage than one would find in a large city. Each person included in the survey kept an exact daily record showing all trips made away from home, the exact route traveled street by street and block by block, the means of travel including walking, the time each trip started and ended. A separate record was kept for each segment of a trip, and the address and kind of estab11 Traffic A u d i t Bureau, Coverage, Showings (New York, 1950). 12 Ibid., p. 3.

Repetition

and Impact

Provided

by

Poster

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lishment at destination and the purpose of each stop were indicated. Data were tabulated to indicate the number of times an individual passed a location of interest to the sponsors of the study. Since a large number of trips was included, it was necessary to invent a method of tabulation. T h e usual tabulation methods for static data are not easily used for the recording of paths or routes of travel. A n ingenious system of templates was devised which simplified the tabulation. T o summarize the contributions of the Fort Wayne, Philadelphia, and Cedar Rapids surveys to the development of methods and techniques for securing and analyzing movement data, information in each case was secured only at residence bases. In the case of Fort Wayne, data for the previous day's travel only were obtained by interview. Information included travel by any means of transportation including walking, but was limited to a primary destination and purpose. In the Philadelphia and Cedar Rapids studies, a panel technique was devised by which participants kept travel diaries that allowed accumulation of information over an extended period— up to four or five weeks. In addition, actual routes of travel were noted as well as the location and nature of each destination and the purpose of each stop. This is the type of data needed for more complete analyses of systems and structures of movement in cities. It is to be hoped that further analyses of the Cedar Rapids data and other studies of similar nature will provide an important contribution to the study of movement of persons. It is to be noted that none of the three studies was concerned with the movement of goods, and only incidentally with the movement of vehicles. Some Selected Measures and

Relationships

In the course of this study an attempt was made to explore measures that would be useful in describing and analyzing systems and structures of movement related to establishments or areas. Several of these measures are presented in this section so that their potentialities may be evaluated through further experimentation by succeeding workers in the field. T h e first consists of a group of ratios, suggested by Wroe Alderson during this investigation, which are

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i n t e n d e d to measure various traffic and land use characteristics; 1 8 the second is a device for estimating the d i s t r i b u t i o n of trip destinations i n an area of assembly; and the third presents a m e t h o d of m e a s u r i n g the relationship b e t w e e n truck trips and land use. A l d e r s o n has d e v e l o p e d three pairs of ratios, each devised to measure some aspect of traffic, land use, or a relationship b e t w e e n the two. T h e first pair emphasizes the k i n d of activity or land use t a k i n g place at a location. T h e second pair attempts to measure the traffic generated at a site and adds the d i m e n s i o n of time and distance w h i c h is missing f r o m the first pair. T h e third pair deals w i t h the linkages existing a m o n g locations a n d the uses to w h i c h they are put. SITE EFFICIENCY AS MEASURED BY MINIMIZATION OF

MOVEMENT

Alderson's first measure is termed the "site-efficiency ratio." It p u r p o r t s to indicate the extent to w h i c h the m o v e m e n t necessary to b r i n g p e o p l e a n d goods together f o r participation in the activities c o n d u c t e d at a specific location are m i n i m i z e d . T h e proposed measure depends u p o n the relationship b e t w e e n virtual m o v e m e n t a n d actual m o v e m e n t , concepts w h i c h are analogous to v i r t u a l and actual displacement in physics. T h e definitions of v i r t u a l a n d actual m o v e m e n t may perhaps be best presented by direct q u o t a t i o n f r o m Alderson: Virtual movement may be defined as the maximum movement of goods and persons that might be directly induced by the activities transpiring at a site, stated in terms of the number of vehicles required to carry this volume of movement. Virtual movement takes no account of the features of a given site that may tend to minimize movement. It is the movement that might theoretically be required by the specified activities regardless of the site, or making the worst assumptions as to site. . . . T o calculate virtual movement for a given site, all of the components of site-induced traffic must be considered. As to persons, the list includes all employees, customers, and suppliers who visit the site each day. If an is Alderson and Sessions Inc., "Movement Study" (unpublished report on work undertaken for the Institute for Urban Land Use and Housing Studies, Columbia University, 1950).

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employee makes trips in and out of plant on business during the day each trip should be counted as a separate visit. If all visitors, including employees, came and went in their own passenger cars they would be contributing to the volume of traffic on both the incoming and the outgoing trip. For ease of comparison with goods traffic it would thus seem wise to count each visit of a person as two movements. Virtual movements on the goods side is based on the number of trucks that would be needed to carry all site-induced goods traffic. This includes the actual movement both in and out. It also includes certain traffic not actually touching the site. One component is all traffic induced by transactions at the site moving to or from other points in the urban area. Another component is the fuel equivalent of all electric power consumed on the site. When fuel is brought to the site to generate power it forms a major component of actual traffic. Even though this traffic is avoided by the purchase of power, the equivalent tonnage must be considered in order to complete the picture of virtual movement. The virtual tonnage both in and out should be assumed to move in standard trucks of moderate size in order to compare the impact on traffic with that of passenger cars. Thus virtual tonnage may be stated as the total number of vehicles required by goods and persons, assuming that persons move in passenger cars and that goods move in truck units which place about the same burden upon streets and highways and upon parking space. . . . Actual movement should also be calculated in terms of total number of vehicles. In this case, however, only those passenger cars are included which actually visit the site. Number of trucks in and out are counted but adjusted to the standard unit. For some purposes it is desirable to preserve the truck data by actual sizes and types. For the present purpose the conversion to standard units is essential so that trucks and passenger cars may be added to get a figure on actual movement in terms of vehicles. T h e site-efficiency ratio is then calculated by dividing the numerical estimates of actual movement by virtual movement. If the use to which a site is put is to be judged solely from the point of view of minimization of movement, then the smaller the ratio, the greater the efficiency of the site. T h i s is a resourceful attempt to develop a usable measure implementing an important concept. T h e term "site efficiency" may be accepted in this sense only if it is rigorously and exclusively defined. It refers only to the comparison of the amount of movement of persons and goods occurring at a site with some estimated "maxim u m " movement. This use of "efficiency" is not to be confused with

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EXPLORATIONS

147

another m e a n i n g current in land economics. 1 4 N e i t h e r should "effic i e n c y " in this sense be taken to m e a n the total effectiveness of a site relative to others in serving the needs or values of the i n d i v i d u a l or g r o u p o c c u p y i n g it. T h e proposal of such a ratio as this springs f r o m r e c o g n i t i o n of a need for d i f f e r e n t i a t i n g the effects of the f u n c t i o n s of an establishm e n t f r o m the effects of its geographic situation in d e t e r m i n i n g the a m o u n t of persons- and goods-movement t a k i n g place i n t o and o u t of the establishment. T h e proposed ratio approaches, b u t does n o t q u i t e accomplish this objective. T h e total activity at an e s t a b l i s h m e n t — t h e n u m b e r of transactions at a d e p a r t m e n t store, for e x a m p l e — i s c o m p o u n d e d of functional and site-induced factors. T h e total n u m b e r of sales transactions and, similarly, the n u m b e r of visitors to the store are affected by its location in an area of assembly f o r s h o p p i n g and other purposes. A large department store e q u i p p e d to serve customers in a small, n e i g h b o r h o o d s h o p p i n g center w o u l d not be expected to attract the n u m b e r of individuals the same store w o u l d attract in a c o n v e n i e n t location w i t h i n the central district of a large city. T h e concept of " v i r t u a l m o v e m e n t " as used by A l d e r s o n needs to be refined, because as n o w used it takes account only of differences in the means of transportation available at a site and used for the goods- and persons-movement to an establishment, and does n o t allow for other situational factors, such as the character of the s u r r o u n d i n g land uses. T h e r e f o r e , its usefulness in its present f o r m is questioned, a l t h o u g h it has b e e n i n c l u d e d in this report to stimulate the t h i n k i n g of others a l o n g this line. T H E GOODS-PERSONS

RATIO

In suggesting w h a t he terms the " l a n d use characteristics," Aiderson writes: T h i s ratio is calculated on a virtual basis rather than an actual basis. T h e number of trucks theoretically called for by an activity is divided by the number of passenger cars required. T h e purpose of this ratio is to serve as a qualitative index of the traffic generating character of an ac11 Richard U. Ratcliff, Urban Land Economics (New York, 1949), p. 354: "Certain sites yield a relatively higher return per dollar of cost incurred than other sites and are said to have a higher efficiency."

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tivity. As in the case of the site efficiency ratio, the land use characteristic can be related to land areas by plotting the ratios for sample establishments on a map. In the latter case there should be an emerging picture of characteristic clusters according to whether goods or persons constitute the primary problem of movement. It is suggested here that the land use characteristic be calculated in terms of number of vehicles as estimated for virtual movement. These estimates would be available anyway if the site efficiency ratio was computed. Otherwise it is conceivable that simpler and more direct ways of stating the relation between goods and persons at a site might serve just as well. Thus tons per thousand persons might be adequate for many uses. It would serve to arrange all kinds of land use on a scale from those involving assembly of persons only to those in which goods are the major factor. Land use so conceived would range from such activities as church services on the one hand to storage warehouses with automatic handling facilities on the other. Most types of manufacturing would require a larger number of persons relatively than the storage warehouse since operations are performed on the goods. Light retailing, or even motion picture entertainment, lies further towards the goods side than church services but the convenient assembly of people is still the primary requirement. After material from the case studies had been analyzed, it was decided that some alternative methods of calculating the land use characteristic should be considered. . . . The other side of the ratio is employees in one case and persons in the other. All three ratios are shown in the summary of findings from the case studies. In its present form, this ratio is subject, like the site-efficiency ratio, to the reservations imposed by employment of the "virtual movement" concept. For instance, in a modern city, large office buildings or department stores may or may not generate their own power, depending upon relative cost. Factors in total activity that are altogether functionally induced and site induced are so intertwined that no present basis is seen for discrimination among them. For this reason, at least for the present, the use of "actual" movement data in calculation of this ratio may be more feasible. In practical application this goods-persons ratio, like the next one, which Alderson has called "traffic-characteristic," may be more effectively employed for areas of assembly than for individual establishments. T h e goods-persons ratio becomes an analytical tool for study of systems of movement; the traffic-characteristic ratio, which

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is defined as the number of truck hours (or truck miles) divided by the number of passenger car hours (or passenger car miles) in site-related traffic, becomes a method of viewing structures of movement. T h e application of such a ratio to parking instead of to moving traffic, as suggested by Alderson, has already been partially attempted in parking studies of urban central districts. THE TRAFFIC-CHARACTERISTIC RATIO

Of his third ratio Alderson writes: [It] is calculated as the number of truck hours over the number of passenger car hours in site-related traffic. It is calculated in terms of the actual number of vehicles moving at the site multiplied by the average number of hours that these vehicles are in motion within the city limits. This ratio is designed to show the character of the load which the activities at a given site place upon traffic facilities. It may turn out that it is more feasible to calculate such an index in terms of mileage rather than hours. It may be necessary at a more refined stage of analysis to develop a parking characteristic as well as a traffic characteristic. T h e latter would appear to be more significant for present considerations. T h e parking characteristic would in a sense be the obverse of the traffic characteristic. That is to say that the number of trucks and the number of passenger cars are to be multiplied by the average number of hours parked at the site rather than while moving in site-related traffic. If such data can be obtained, this ratio may be used in analyzing all site-related traffic within an area, or of all site-related traffic on certain channels of movement. THE TRAFFIC-BURDEN

INDEX

Like the traffic-characteristic ratio, Alderson's "traffic-burden index" may be more significant when used for an important area of assembly, such as a central district, than for an establishment. A less important area of assembly, such as a manufacturing district, may be related to either an entire city or an appropriate section of a city, or to certain traffic channels. Of this index, Alderson writes: This index is calculated as the number of vehicle hours for the site divided by the number of vehicle hours for the city. It is presumed that vehicle hours for the city can be estimated fairly closely by taking all

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vehicles moving on a typical day and multiplying by the average number of hours in motion, for trucks and for passenger cars separately. T h e purpose of the index is to measure the relative importance of the site in generating a share of the total city traffic. T h e index would obviously be a very small decimal fraction in the case of small establishments or residences. It might not be worthwhile to calculate it except for large establishments and groups of smaller places. Here again it may be worthwhile for some special analytical purposes to calculate a separate parking burden index. THE PAIRED-LINKAGE FACTOR

For measuring the movement system between two related establishments, Alderson suggests a pair of coupled quantities which he calls the "paired-linkage factor." Of this he writes: T h e term linkage is used here to characterize the kind of connection between establishments that would lead to movement between them. This definition does not embrace all the motivations and considerations that would link two establishments such as common ownership, or a common desire for attractive surroundings or a prestige address. If linkage is limited at the first stage of analysis to the need for moving goods or persons between two establishments, then the key to satisfactory quantification may be number of transactions. Persons usually get together to effect transactions. Movement of goods often results from these transactions. If the transactions of two establishments were primarily with each other they could obviously minimize movement by occupying adjacent locations. T h e smaller concern would probably gravitate toward the larger, particularly if the smaller was the supplier and the larger the customer. Dominant paired linkages of this kind are known to occur. T h e General Casting Company sells more than half of its output to the Baldwin Locomotive Company and occupies an adjacent site, even though it is under independent ownership. Paired linkage would not usually be as great as this but might still exercise an important influence on site selection. T o calculate the paired linkage factor it is first necessary to determine the number of transactions in which each firm is involved, counting all suppliers and all customers. Next it is necessary to know the number of transactions which the two firms have with each other. T h e number of common transactions is then calculated as a percentage of the total transactions for the smaller company and as a percentage of the total transactions for the larger company. T h e factor would be expressed as two figures joined by a hyphen, as in the rating of eyesight. Thus a paired linkage factor of 30-15 would mean that common transactions repre-

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sented 30% of all transactions for the smaller company and 1 5 % of all transactions for the larger company. Parallels to this type of linkage can easily be found in foreign trade. Before the war our foreign trade with Japan was considerable. However, it amounted to 50% of the total foreign trade of Japan and less than 1 5 % of our total trade. As in foreign trade, so in paired linkage, two percentages are necessary to describe the relationship. T h e two percentages indicate both the magnitude and the direction of the pull. T h e paired-linkage factor has b e e n c o n c e i v e d as based u p o n transactions b e t w e e n establishments. It can also be applied to movem e n t b e t w e e n establishments stated in shipments, tons, persons or trips. It can also b e applied to groups of establishments in subareas of assembly. T h e A l d e r s o n paired-linkage concept may be e x t e n d e d to measure the association between establishments that serve c o m m o n customers, as w e l l as those that are l i n k e d by transactions. A test measu r e m e n t of the f o r m e r type of linkage was made by u t i l i z i n g interv i e w data o b t a i n e d at two establishments in Philadelphia. T h e large department store and the specialty shop at w h i c h interviews w e r e held are located on opposite sides of a m a i n s h o p p i n g street in adjacent blocks. A sample of individuals l e a v i n g each establishment, was asked w h a t other establishments in the central district they h a d visited since leaving a base of operations b e f o r e c o m i n g to the store and also w h a t establishments they i n t e n d e d to visit in the central district b e f o r e g o i n g to a base of operations (generally h o m e or workplace). T h e r e were 47,592 visitors at the d e p a r t m e n t store and a p p r o x i m a t e l y 635 at the specialty shop. 1 5 O f these, r o u g h l y 230 persons visited b o t h establishments, or 0.5 percent of the visitors to the d e p a r t m e n t store and 36.2 percent of the visitors to the specialty shop visited both establishments. 1 6 P l a c i n g the smaller establish15 A l t h o u g h an actual door count was not taken at the specialty shop, the interviewers estimated that the sample of 127 persons comprised roughly 20 percent of the total visitors. i s In the 0.5 percent sample of persons visiting the department store, no respondent stated that the specialty shop was or would be one of his destinations, but many planned to visit other unspecified places after leaving the store. O f the persons interviewed at the specialty store, forty-six stated that they had visited or intended to visit the department store that day. It was assumed that this figure multiplied by the sampling ratio approximated the number of persons w h o visited both places in the course of their trip.

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ment first, this pair may be expressed in Alderson's terms as .362.005. THE GROUP-LINKAGE FACTOR

In an attempt to devise a measure for the common linkage among establishments within a group, Alderson suggests the "group-linkage factor," of which he writes: The group linkage factor is conceived in a purely behavioristic way and hence is as readily subject to quantification as is the paired linkage factor. In neither case is there any desire to minimize underlying motivations, but clearly it would be most difficult at this stage to try to quantify them. T h e choice of transactions rather than volume of movement for the quantification of linkage is an attempt to choose an aspect of behavior lying somewhat closer to the motivations behind the movement. As compared with the paired linkage factor, the group linkage factor is an attempt to express the degree of linkage in a single ratio. While it can be applied to the group of only two establishments it is designed particularly to deal with larger groups. It is based on the simple twoway division between transactions within the group and transactions involving a member of the group and an establishment outside the group. Once more a parallel from foreign trade may be suggestive. Great Britain and some other countries comprise the sterling group. Transactions within the sterling area have a different significance from transactions between members of the sterling group and outside countries. T h e first step in calculating the group linkage factor is to determine the number of transactions in which each establishment is involved and hence the total number for the group. The next step is to determine the number of these transactions which are internal, or, in other words, transactions between two members of the group. T h e precedure would be to obtain the number of internal transactions in which each member is involved, compute the total and divide by two. By the method of collection followed, both ends of an internal transaction would be counted, and hence it is necessary to take half of the total to make the figure really comparable with the total for all group-related transactions. T h e final step is to divide the number of internal transactions by the total number of group-related transactions to obtain the group linkage factor. One point which has been left open is the definition of the group. T h e need for the group linkage factor was first visualized in the case of clusters of similar establishments, such as the wholesale jewelry market on Sansom Street, or the wholesale produce market on Dock Street. It is believed that in both cases establishments within the area have a number

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!53 of transactions with each other as well as with outside establishments. These internal transactions may offer a partial explanation of the cluster and their relative importance would be indicated by the group linkage factor. It might be necessary, however, to define groups in other ways to deal with the problem of linkage. Thus a group might be related firms located at various points in the urban area. At the present time, however, it is difficult to see how the study of such a group could be related to the basic principle of the minimization of movement. If the firms included in a group are scattered, then obviously the linkage among them is not such as to make them draw together in order to reduce traffic. A more productive approach might be to set up a separate concept of destination or goal linkage as compared with direct linkage by common transactions. Thus the primary linkage among establishments in the wholesale food market probably lies in the shopping habits of their customers. Careful buyers may want to look over the total supply before making a purchase from a single establishment. Thus it is the number of establishments called upon by the average customer before a purchase is made that becomes significant. Calls per completed transaction might be obtained for such business clusters by interviewing a cross-section of persons from outside doing business with establishments in the cluster. If calls per transaction are relatively high there is a strong case for preserving the integrity of the cluster. In the heart of any large city there is bound to be a considerable amount of purely coincidental proximity. Establishments are closer together because they are individually trying to get as close as possible to rapid transportation or some other facility. Coincidental proximity should not be confused with true linkage. The term linkage might properly be restricted to connections based on direct relations of establishments with each other, or of an outside group, such as customers, with establishments in the cluster. It may be, however, that prestige linkage is partly a product of coincidental proximity. Leading establishments which have the greatest choice as to site may tend to value the same site characteristics. The cluster that results may have prestige attached to it because of the presence of these leading establishments. Lesser establishments may then locate in the same area for reflected prestige rather than for more positive and measurable advantages. T h e group-linkage factor may also find other applications than those suggested by Alderson. If the meaning of the term "linkage" is enlarged somewhat, it may be taken to represent the relationship of a residential area, for instance, to one or more competing shopping centers. Likewise if a shopping center is located in a residential community, the same concept may be used to describe the propor-

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tion of persons coming to the center from within the community to all visitors to the center. In terms of the analytical framework proposed in this report, some of the Alderson ratios may be used as tools to describe or analyze systems of movement; others, with specific time-place implications, such as the traffic-characteristic ratio or the traffic-burden index, may apply to particular structures of movement. APPLICATION

OF THE ALDERSON

RATIOS

Four of the ratios were calculated by Alderson in an analysis of data obtained in three "case studies" of business establishments, chosen and investigated for the purpose: the home office of a large industrial corporation located in the central district; the plant of a large manufacturing concern outside the central district; and a large department store located in the central district of Philadelphia. It was believed that the three cases would present characteristic problems that would be encountered in further studies of this type. 17 T h e two ratios having to do with linkage were not included because they could be tested only on the basis of information about transactions either for pairs of related establishments or for groups of establishments in relation to others outside the groups. COMPARATIVE TRAFFIC RATIOS FOR THREE BUSINESS ESTABLISHMENTS

Ratio

Site-efficiency

Case i Large Office Building

Case 2 Large Industrial Concern

Case 3 Large Department Store

0.2000

0.6300

0.0083

Land use characteristic Trucks/automobile Tons/employee Tons/person

0.0302

0.0800

O.OO39

O.237O

0.9900

0.0125

0.1730

0.0078 a

Traffic-characteristic Traffic Parking

O.O473

0.0107

0.0078

O.OO14

I.O354 a

Traffic-burden

O.OIGO

0.0814

0.11 go

a Data insufficient to compute ratio. IT A statement of the methods and techniques used in these case studies is given in Appendix A.

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155

In writing of his attempt to use the four ratios, Aldersons says: Several different approaches were tried in the case of the land use characteristic. Under # 3 effort was made to set up a parking characteristic as well as a traffic characteristic. The formulas and methods of calculation are described below: _ . . Actual Movement 1. Site efficiency ratio = ^r. r^r 1 Virtual Movement Actual Movement = Number of vehicles actually terminating trips at site during operating period. Virtual Movement = Hypothetical number of vehicles, assuming that all persons arrived by personal automobile and that all goods arrived in 2 y 2 ton trucks fully loaded. Persons = Employees plus all others visiting location for any purpose connected with its activities. Goods = All materials, fuel and supplies delivered and all products or waste shipped out. Since some of these data were obtained on a sampling basis they had to be multiplied to get figures comparable with total volumes. All figures in turn had to be adjusted to a common operating period. , , . . Virtual Trucks 2. Land use characteristic = — — Virtual Automobiles The purpose of this ratio is to get some measure of the relative importance of goods movement and persons movement for the establishment studied. It is computed on a virtual basis because the measure should be in terms of traffic requirements inherent in the activity without reference to the relative efficiency of the site. Other attempts to get at the goods-persons relationship included the following: , , . . = — Virtual Tons Land use characteristic , r-=r Number of Persons Of less general validity but possibly suitable in certain cases, is the variant, , use characteristic , ^ . . = Virtual — Tons T Land Number of Employees 3. Traffic characteristic = (Actual Number of Trucks) (Average Duration of Trip) (Actual Number of Automobiles) (Average Duration of Trip) The traffic characteristic is an attempt to characterize the kind of load which an establishment places on the traffic facilities of the city. The use of facilities by a single vehicle is taken to vary with the number of hours it is on the road. 3a. Parking characteristic = (Number of Trucks) (Average Time Parked) (Number of Passenger Cars) (Average Time Parked)

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4. Traffic burden = Truck Time on Road -f- Passenger Car Time on Road. Site Related Traffic Burden 4a. Traffic burden index = Total City Traffic Burden Using these methods of calculation and the quantitative data obtained in the case studies, Alderson developed the table that appears on page 154.

Assembly-Area

Profiles

What is the relative attracting power of various kinds and combinations of establishments (considered as space uses) within an area of assembly to a given population known to be in that area of assembly? T h e location of stops at establishments made by a population interviewed at one location may be considered indicative of this relative attraction if allowance is made for distance from the interview point and for the amount of floorspace occupied by the kinds of establishment. In this analysis the assembly area is taken to be the area within which are located all other destinations visited on the same trip by individuals interviewed at a particular establishment. If these locations are mapped, and the number of destinations within each tier of blocks north-south and east-west is counted, a pair of "profiles" representing number of stops in each direction may be drawn. Following this, a theoretical distribution of the same total number of stops within an assumed radius of the establishments is abstracted on the basis of (1) the assumed friction of distance, and (2) the assumed attractive power of the total amount of undifferentiated nonresidential floorspace per block. When a theoretical profile is drawn, taking into account only those two factors as influencing a deviation from a uniform distribution of stops, it may be compared with the actual profile of stops. T h e difference is expected to represent the further effect of specific "land use" attractions as an undifferentiated residue of all possible factors, in causing deviation from a uniform distribution of stops. T h e analyzing of assembly areas by means of profiles, then, is an attempt to find a workable means of isolating the relative "valences," based upon kind of land use of various parts of an assembly area, to a population congregated at one kind of establishment.

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1 5 7

Assembly areas related to individual establishments—which have been described as summations of overlapping destination areas of the populations interviewed at those establishments—are substantially indicated on the spot maps of establishments visited. East-west and north-south profiles of these "assembly areas" may be constructed, as indicated in Figure 14, which represents assembly-area profiles for a retail specialty store in downtown Philadelphia. Schematic

Map N u m b e r of Stops

Philadelphia Central District

Number of Stops in E a c h Row of B l o c k s

^

Location of S t o r e

FIGURE

14.

PROFILES:

ASSEMBLY-AREA RETAIL

CIALTY

Columns

SPE-

STORE

of B l o c k s

Number of Stops in E a c h Column of B l o c k s

T h e profile (east-west, for instance) is constructed by totaling the number of stops in each north-south column of blocks and drawing a curve in such manner that the east-west scale represents blocks in an east-west direction, with ordinates at the center line of each north-south tier of blocks. As a descriptive device the pair of profiles for an assembly area

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allows a comparison of the concentration and spread of stops in each direction, which gives a first approximation of land use attraction to the population at the establishment. An inspection of the two profiles in Figure 14 immediately raises questions concerning their odd shapes—their peaks and valleys and their skewness, their relative heights, and the difference in the breadth of their bases. Obviously, certain locations had much greater attractive power to individuals who visited this establishment than other locations. T h e question arises: Is it possible to develop a method for measuring the difference in attractive power of areas to a group of individuals who are assembled at a spot? Is it possible in this way eventually to measure the mutuality of establishments within an area of assembly? Since the actual profiles show the incidence of other stops by tiers of blocks, can one develop a theoretical profile which would indicate an expected distribution of stops within the same tiers of blocks under certain assumptions? Let us consider that a certain number of persons are congregated at an establishment located at a given point in a block which is situated in an area of assembly, and attempt to predict the distribution of subsequent stops that they will make as a result of forces of attraction and repulsion playing upon them. Assume first that (i) this population will make a certain number of stops within a given area, (2) that distance is not a deterrent, (3) that opportunities are homogeneously distributed within the area, (4) that the goals associated with the opportunities are of equal importance, (5) that there are no impediments of terrain, or other factors dictating selection of destinations. Under these conditions, one would expect the distribution of subsequent stops made by persons at the given establishment to be of equal density throughout the area. If the area is now marked by a rectangular grid representing streets and blocks, one may select for consideration the group of blocks that fall within a "diamond," in the center of which is located the establishment under consideration (see Figure 15A). Since equal density of visits is expected in each of the blocks, a weight of one may be assigned to each block. T h e shapes of the eastwest and north-south profiles will be the same, and will be equiva-

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>59

1

1

1

1

1

I

1

1

1

1

I

1

F

1 A FIGURE

15. ASSEMBLY-AREA

B

PROFILE:

3 . CASE

I

lent to the distribution of the number of blocks in each column (or row) of the diamond (Figure 15B). If it is now assumed that only the limitations imposed by distance, of all possible factors, will exert an influence upon the locational distribution of stops, one can then say that establishments near the given location will attract more persons than establishments farther away, or in general, the number of visits made to other establishments may be expected to be only a function of the distance from the central point of consideration. Hypothetical weights may be assigned to each concentric "diamond" of blocks which reflect this functional relationship. These weights indicate the number of visits that may be expected in each of the blocks. A hypothetical weighting system of this sort is presented in Figure 16A. 7 8

3

12 48

40

14

9

8 4

3

12

1 A

B FIGURE

16. ASSEMBLY-AREA

C PROFILE:

CASE

II

T h e east-west profile of this diagram is again the sum of the columns, but now the weights are considered rather than the blocks alone (Figure 16B). As the profile is constituted, the sum of the column weights is equal to the square of the weight of the item in the middle row. Thus, if x is the expected number of visits in any column and d is the weight of the item in center row of that

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c o l u m n , then x = d2.18 If the profile is then plotted as a c o n t i n u o u s curve rather than a histogram, the resultant figure may b e considered to b e the distance-density c u r v e (Figure 16C). T h e distance-density curve represents the shape of the profile that may b e expected if the total n u m b e r of visits m a d e b y persons at the focal p o i n t were to distribute themselves o n the basis of distance alone and if the distance f u n c t i o n were as assumed. In the p r e c e d i n g paragraphs, the possible effect of distance o n the d i s t r i b u t i o n of visits was postulated. R e t u r n for a m o m e n t to the assumption that distance is not a consideration, and n o w assume that opportunities a n d the goods associated are n o t u n i f o r m l y dist r i b u t e d or u n k n o w n , b u t that they are related to the intensity of land use. A p r e l i m i n a r y and u n d i f f e r e n t i a t e d measure of land use intensity is the n u m b e r of square feet of b u i l d i n g floorspace in a g i v e n b l o c k . T h u s , if distance is n o t a factor, a n d n o influences other than land use intensity operate, then the total n u m b e r of stops w i l l be p r o p o r t i o n a t e to the d i s t r i b u t i o n of total nonresidential

floor-

space b y blocks in the d i a m o n d (Figure 17A).

FIGURE

1 7 . ASSEMBLY-AREA

PROFILE:

CASE

III

T h e profile representing the distribution of visits w i l l then be represented b y a histogram i n d i c a t i n g the percentage d i s t r i b u t i o n b y c o l u m n s of the total floorspace, a n d the n u m b e r of visits i n each c o l u m n w i l l then be p r o p o r t i o n a l to the h e i g h t of the histogram bar (Figure 17B). If the histogram is smoothed to a c o n t i n u o u s curve the results may be termed the floorspace-density curve. T h i s c u r v e represents the d i s t r i b u t i o n that m i g h t be expected if the total is Accordingly, if d is the weight of the center block, then the number of blocks in a destination diamond equals d* + (d — 1)2 and the sum of the distances weights for all blocks equals d-^^-àZ-Lh

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161

number of visits were distributed only in accordance with undifferentiated land use intensity as represented by the relative amounts of nonresidential floorspace (Figure 17C). If the influences of both floorspace and distance are permitted to interact, with all other factors held constant, the attracting forces reflected by floorspace and the repulsive forces due to distance can be resolved into a single force. We may then postulate that the resultant force will attract persons in proportion to its magnitude, i.e., that the density of visits in each block will be proportional to the percentage that the force of that block is of the total for all blocks in the diamond. The force of each block in the destination diamond may be computed by weighting the percentage of total floorspace in the block by the distance weights associated with each block (Figure 18A).

FIGURE 18. ASSEMBLY-AREA PROFILE: CASE I V

The profile shown in Figure 18B reflects the combined influences of distance and floorspace. Smoothing the histogram yields a spacedistance curve which represents the distribution of visits that would result were distance and undifferentiated land use intensity (crude amount of nonresidential floorspace) the only influences operating in the distribution of persons visits to various locations (Figure 18C). T h e theoretical space-distance curve (for an establishment) may then be compared with a profile or curve derived from an actual count of stops made by persons interviewed at the establishmentpoint. If theoretical and actual curves coincide, we may then conclude that floorspace and distance alone, as combined in the functional relationship postulated previously, accounted for the distribution of visits, or that the other factors distributed themselves in

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the same fashion as the influences of space and distance. It is very unlikely, however, that the actual curve will coincide with the theoretical. T h e divergences of the actual from the theoretical distribution may then be considered to be a resultant of a bundle of other factors which play themselves out in the selection of destinations. These are related to what people want, what they think they can get, and where they think they can get i t — i n other words, the dynamic association between needs, goals, and land use. Interwoven in this fabric is type of land use, the symbolism of space, and a host of fortuitous factors, each of which may be ephemeral for an individual, but persistent statistically. For these points on the ordinate where the actual curves differ from the theoretical, we may assume that the type of land use and associated goals are asserting influences which are disproportionate to crude floorspace and distance measures. At points, or columns of blocks in the case of profiles, where the actual curve exceeds the hypothetical, the land use pattern of the blocks in the column has greater powers to attract pedestrian traffic than could be anticipated from floorspace and distance alone. Similarly, where the actual curve is lower than the hypothetical curve the traffic attracting potential is less than might be anticipated on the basis of floorspace and distance alone. T h e points where the two curves intersect do not necessarily show a conformity of the actual curve with the spacedistance prediction, but rather represent space-distance balance points in the distribution of actual stops resulting from the concentration of stops at certain locations. A n illustration of the system can be given from data secured in the course of the interview survey on stops made by visitors to an establishment, and estimates of gross floorspace by blocks derived in the Philadelphia central district study. A n empirical profile was calculated for all stops made by persons who visited a retail specialty store in the course of a day during the spring of 1950. Each stop was tallied according to the block in which it occurred and a profile derived from the block tallies. T h e profile was similarly calculated for the theoretical distribution of visits made by persons who stopped at this establishment. In delineating the destination diamond, the maximum value of d

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163

was taken to be equivalent to the distance in blocks between the subject establishment and the location of farthest establishment visited by any person in the course of his journey in the destination area. O n the basis of data secured in the course of the interview survey, the maximum value of d was found to be nine. T h e block in which the subject establishment is located was taken to be the center of a destination diamond. Distance weights were assigned to each concentric diamond of blocks, beginning with nine for the center block and decreasing for each successive diamond away from the center. T h e distance-density profile based upon the apportionment of distance weights is shown in Figure 19 along with the profile based on the actual distribution of stops.

m 60

o. o w FIGURE

1 9 . DISTANCE-

D E N S I T Y PROFILE

M

4 0

I>

£ 3

2 20

0 3 6 9 6 3 0 W e i g h t s in Middle R o w of Diamond

T h e east-west profile of actual stops which have as their focus the retail specialty shop, is in the shape of a sharp bimodal distribution, with the heaviest concentration (26 percent of total stops) falling in the tier of blocks one block west of center, and a secondary mode (17 percent of total) in the column four blocks east of center. T h e modes are quite distinct with a deep valley between them, and tend to convey the impression that the given profile may actually be a composite of two separate distributions. From each of the peaks the volume of stops drops sharply and then begins to taper as the distance from the maximum increases. T h e distance-density profile consists essentially of segments of two parabolic curves. T h e theoretical distance profile is symmetrical

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with a maximum in the center column representing 17 percent of total stops. The two tails of the curve shade from the peak in proportion to the square of the distance weight in the center row of the distance diamond. T o achieve comparability between the theoretical and actual profiles, the area under the theoretical was equated to the total number of stops, applying a constant factor K to the sum of the distance weights in each column in the distance profile. K was calculated by dividing total stops by the sum of all the distance weights in the profile. A comparison of the theoretical distance-density profile and the profile based on actual stops reveals only vague similarities. While the extremities of the theoretical and actual profiles from o to 7 west and from 4 to o east are fair approximations of each other, neither of the two peaks of the profile of actual stops occurs in rows of maximum theoretical density. Moreover, the profile of actual stops displays a sharp contraction in Column 7 east, while the theoretical curve declines smoothly from a maximum at the center to zero in Column O east. The sum of the absolute differences between the actual and theoretical values for each of the columns amounted to 135.16, or an average discrepancy of eight per column. T w o thirds of the total discrepancy, however, falls in three of the columns: 8 west, and 7 and 5 east. Variations of similar magnitude are revealed when the differences between the actual and theoretical values for each column are taken as a ratio of the theoretical value for the column. The error ratios range from —1.00 to +2.31. Because of the two pronounced peaks, there are only two instances of an excess of actual values over theoretical values, the remaining columns showing negative ratios. The floorspace-density profile provides a clue to the bimodality of the profile based on the actual number of stops. The floorspacedensity profile was constructed by summing the floorspace for the blocks in the diamond falling within each row of the profile (Figure 20). A constant factor Q equal to the number of stops divided by total floorspace was then applied to the sum for each column. The resultant theoretical space profile revealed a major peak which

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165

occurs in the same column as the principal concentration in the profile based on actual stops, and two minor peaks, one of which coincides with the secondary mode in the actual profile.

FIGURE

20.

DENSITY

FLOORSPACEPROFILE

0 3 6 9 6 3 0 Weights in Middle Row of Diamond

Thus, while the major peak in the number of actual stops is one column removed from the high point of the distance-density profile, it nevertheless is adjacent to it, indicating part of the role played by the factor of distance. The peaks of the floorspace-density profile occur in the same columns as the peaks of the actual profiles, which hints at the pull that is exerted by the land uses which may be associated with the crude measure based on floorspace alone. A floorspace-density profile was constructed in order to reflect the interacting influences of the repulsion of distance and the attraction attributable to volume of floorspace. This was done by weighting the distance factors assigned to each block by the proportion of total floorspace in the destination diamond contained in the block (Figure 21). The profile resulting from the amalgamation of the two factors represents the expected distribution of stops, if distance and floorspace alone are considered. As one would expect, the space-distance profile bears some of the characteristics of the distance-density and space-density profiles. It has the jagged variations of space profile alone and some of the compactness of the distance profile. The space-density profile shows a major peak in Column 8 west and two minor peaks in Columns 7 and 5 east, as does the distribution based on floorspace alone. One

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w 0 40

u

U

1

20

of the major ettects ot consolidating the two influences was to increase the concentration in the major peak, pulling the theoretical profile closer to the actual in this column. T h e error ratio for the peak column was reduced from 1.04 for the distance-density curve and .87 for the space-density curve to .44 for the combined curve. T h e error ratio for the column containing the secondary peak (Column 5) was 2.31 for the distance profile, .89 for the space profile, and 1.31 for the space-distance estimate. T h e absolute sum of the deviations between the actual and theoretical profiles which stood at 135 for the distance and 150 for the space profiles, declined to 1 1 7 when the two influences were amalgamated. T h e distance weights which have been arbitrarily assigned in this illustration, may perhaps be better evaluated through a study of the factors which influence people's walking patterns in an area of assembly. A person in an area of assembly is undoubtedly attracted to many possible destinations but actually visits a small number of establishments in the course of a single trip. T h e selection of destination is a function of many diverse factors, the relative importance of goals associated with establishments, the cost in time, money and energy, and the character of the area through which he must pass to reach the destination establishment. T h e distance that an individual will walk to reach a given establishment is dependent upon the amount of time and energy he is willing to expend, the pleasantness or unpleasantness of the process he must experience

SELECTED EXPLORATIONS

167

in order to achieve either a unique transaction at a particularized destination, or to explore the "market" for potential transactions. T h e attraction of the potential transaction is thus balanced against the functions of space which includes, among other possible influences, the expenditure of time and effort. The nature of experiences anticipated in the course of the journey may operate as an incentive or deterrent. In many cases the role of this factor may be marginal, while in others the journey itself may be the determinant. The willingness to undertake travel on foot differs among individuals. A man's consciousness of the pressures of time in many cases is a function of personality rather than of schedule. The energy people have to expend is affected by sex, age, and physical condition, as many studies of fatigue have demonstrated. Fatigue studies have also shown that interest and incentive serve to delay the point at which performance declines, but interests vary widely among individuals. In this instance, interest may be considered to comprise the goal, the associations of the intermediate area, and the act of walking itself. Various studies have indicated that a small but not insignificant proportion of the urban population derive an illdefined but decided gratification from the rustic pastime of "taking a walk." It must be borne in mind that the attraction-repulsion forces pertain not to all persons but to a particular person, at a given time, in a particular situation. This in essence is the definition of valence which has been discussed previously in another context. Further study is necessary to determine the possibility of quantifying the factors which influence walking distance. It may be possible to derive indexes which evaluate the attractive force of a destination, and the magnitude and direction of forces resultant from the conditions precedent to arrival at that destination. Of these, distance is only one factor, the effect of which is dependent upon the predisposition of the individual in his circumstances of the moment. Whether factors so elusive and ephemeral will lend themselves to statistical treatment has yet to be explored. Locations of major arrival points and departure points in an assembly area undoubtedly exert a dominant influence on the patterns of land use and pedestrian patterns. Neither this nor the influence of linkages between establishments was considered in the above

168

SELECTED EXPLORATIONS

discussion. Consideration of the linkage factors may further explain the differences between the actual and theoretical curves in Figure 21. As was noted in the discussion of the destination-area maps, Figures 3 to 6 inclusive, the stops for all establishments are strongly influenced by the Market Street department stores. This is especially evident in the case of the retail specialty shop (see Figure 3). T h e formulation of the theory of destination profiles emerged in the course of the analysis of data on stops secured in the interview survey at establishments. As a consequence of this post facto development, the data do not conform with all the theoretical requirements implicit in the construction of profiles. Thus, the shape and magnitude of the empirical profiles must be taken as illustrative of a method of construction. Similarly, the comparisons between the empirical and theoretical profiles are indicative of types of analysis rather than of actual situations. T h e data on stops secured in the interview survey 19 were derived from a crudely designed sample which did not permit expansion to an estimate of total stops by location. T h e number of total stops used in the construction of the empirical profiles was based only upon those stops made by persons who were actually interviewed and not on the number of stops made by all persons visiting the establishment. Thus, the areas under the empirical profiles are substantially less than those which would be based upon all stops, but proportionate to the sampling ratios. T h e values estimated for the constants K and C are similarly understated. Because of the limitation of the sample data, it is also likely that the locational distribution of stops made by all visitors will vary from the distribution of stops included in the sample, and consequently the shape of the total empirical profile will be at variance with the one presented previously. According to the conditions laid down for the development of profiles, stops refer only to those visits made by persons after they leave the establishment, and at each successive stop, the person is confronted with a reiteration of distance and floorspace influence in the selection of subsequent destinations. T h e data obtained from is T h e primary purpose of the questionnaire was to investigate the types of data that could be secured through interview surveys of persons at establishments.

SELECTED EXPLORATIONS

1 6g

the questionnaire include visits made in the destination area prior to the respondent's arrival at the subject establishment and a listing of stops which the respondent intended to make after leaving the establishment but prior to returning to a base. Thus, the quality of the data which do not conform with the theoretical requirements (i.e., stops prior to arrival) is superior to the data which conform more closely (i.e., stops subsequent to departure). It may be assumed that the respondent gave a fairly accurate account of stops made between the last base visited or his arrival point in the area and his visit to the subject establishment, but the account of intended stops undoubtedly varied both in number and location from those actually made after leaving the store. Ideally, of course, the profiles would have more meaning if an account of all stops could be secured from persons who "emerge into" the central district or any other area of assembly, at their arrival points, where they leave transportation. In the foregoing illustration, despite the limitation of data, all stops prior or subsequent to the visit to the establishment were lumped together in the construction of the empirical profiles. In essence then, the entire illustration is hypothetical in character and has no further pretensions. T h e principal purpose of the presentation in this section, as in other statistical sections of this volume, is to suggest possible ways in which data pertinent to the relationships between the movement of persons, goods, and vehicles and urban land use may be viewed and analyzed. If the basic idea is deemed to have a core of merit, further studies will undoubtedly sharpen and clarify the concepts and design means of securing data which will more closely conform with them. Relationship between Truck Trips and Land Use It has been stated in a previous chapter that the systems of movement based upon kind of establishment at origin and destination are the most directly relevant to urban land use patterns. T h e statistical representation of this system should ideally be made in terms of the various categories of establishments at origin or destination for which specific systems of goods-movements are described. Although the existing body of data cannot as yet be organized precisely

170

SELECTED

EXPLORATIONS

in this form, a first approximation can be made. This approximation consists of measuring the gross impact of undifferentiated goods-movement per unit of time expressed in terms of truck stops at locations characterized by various patterns of land uses. DATA FOR T H E

ANALYSIS

In the survey of the central district of Philadelphia 20 estimates were made of geographic distribution of the number of nonresidential establishments and amount of space used by various classes of establishments. T h e broad classification of establishments in the report of the Philadelphia Study does not coincide with the groupings outlined in Chapter VI, but there is sufficient similarity to validate their use. Data on the various goods-movement systems, which are viewed in terms of the major categories of origin-and-destination establishments, are available only in fragmentary form (see Chapter VI). T h e Philadelphia Origin and Destination Survey 21 and a recent survey sponsored by the Philadelphia Highway Traffic Board 22 both present data on the number of truck operations associated with certain locations. T h e O & D Truck Report tabulations indicate the number of trucks originating in and destined to each of the O 8c D zones. T h e truck survey conducted under the auspices of the Philadelphia Highway Traffic Board provides a detailed count of trucks, standing, loading and unloading, by type of truck, by standard blocks for half-hour intervals. 20 Philadelphia Central District Study, prepared by Alderson and Sessions for the Philadelphia City Planning Commission (Philadelphia, 1950). 21 Zone Tables—Pennsylvania Vehicle Trips and Zone Tables—All Trips Crossing the Delaware River, Philadelphia-Camden Area Traffic Survey, Pennsylvania Department of Highways and the New Jersey State Highway Department in cooperation with the Public Roads Administration and the Philadelphia City Planning Commission, 1949 (referred to in this study as " O & D"). These tabulations present estimates of the number of truck trips originating in and destined to each of the O & D zones, based upon the O & D sample survey conducted June-November, 1947. 22 "Philadelphia Central City T r u c k Survey," submitted to the Philadelphia Highway Traffic Board by A. B. Blankenship & Associates, Inc., March, 1950. T h i s report, referred to in this study as P C C T S , presents data on the number of trucks standing, loading, and unloading during business hours by location and type of truck. Data were collected by half-hourly count at each location for a day during the latter part of January and the first week in February, 1950. Summaries are available only for the number of trucks by type per block.

SELECTED EXPLORATIONS

171

N e i t h e r the O & D tabulations presently available nor the Traffic Board's truck survey indicates the type of c o m m o d i t y picked u p or delivered, and consequently it is not possible to segregate the various goods-movement systems. T h e m o v e m e n t pattern represented b y the truck stops at various locations, however, can be considered as the gross impact of all goods systems, undifferentiated as to types of system. CORRELATION BETWEEN FLOORSPACE AND TRUCK

IMPACT

R e l a t i n g truck stops or destinations to land use posed the probl e m of d e t e r m i n i n g an appropriate measure for the latter. T h e v o l u m e of goods-movement is related to b o t h type and size of establishment. Size may b e measured in such terms as space occupied, n u m b e r of employees, gross or net i n c o m e or sales, v o l u m e and type of goods handled, or n u m b e r of shipments. Some of these measures are m o r e applicable to one type of establishment than to a n o t h e r a n d in f u r t h e r study it may be desirable to test the areas and extent of their applicability. F o r i m m e d i a t e purposes, however, the a m o u n t of space used by various types of establishment appears to be the most general relevant measure, and one for w h i c h data c o u l d be secured. Estimates of floorspace for each of six basic classes of establishments were derived for each block in the central district in the course of the preparation of the P h i l a d e l p h i a central

district

study. 2 3 T h e s e figures were summarized by O & D zones or groups of zones and floorspace data related, first, to the n u m b e r of O & D truck destinations, and second, to the n u m b e r of P C C T S truck stops. 24 F r o m the attached scatter diagrams (Figures 23 and 24) it can be seen that the n u m b e r of truck trips (either O 8c D or P C C T S ) tends to increase as the total floorspace increases and that the relationship appears to be linear. (First degree regression lines fitted to the data are y = 312 + -Mox 23

[where y = estimated n u m b e r of O & D truck

T h e six basic land use categories are: manufacturing, wholesaling with stocks, wholesaling without stocks, business services, retailing, and consumer services. Grouping of zones was necessary when zone boundaries, basis for O & D data, cut across standard CPC blocks, basis for PCCTS data. There were thirty-three such groups. See Figure 22.

M I D 03 h HH H Z

XX HH

LOMBARD ^^^^^^

S S S > S S S

« o

W W W W W M H W W W W WW - • r j f * i ' > j * L n * o r - c o c - o —• im c*

FIGURE 2 2 . ZONES AND GROUPS OF ZONES CORRESPONDING WITH P . C . P . C . BLOCKS Source: Adapted from O & D Survey; zone groupings indicated by heavy lines

I

6000

d o N o o

I

I

«

• 4000

H JI u 3 u H

312+ .540«

• 2000

W-W-'y^

• • «

10 15 20 Floor Space in Millions of Square Feet (x) FIGURE 23. FLOORSPACE AND N U M B E R OF T R U C K F o r 33 O & D Zones in C e n t r a l District Source: Data drawn from O & D Survey

TRIPS

SELECTED EXPLORATIONS

173

2000

— « 1500 e

•

o N 0 0

%

/"•"Vr-iei • JOII

**§• 1000

10 x u 3 u H

500

• •

•

• • /y

v y ^

Vf» » •

1

• S

10 15 20 Floor Space in Millions of Square Feet (x)

FIGURE 2 4 . FLOORSPACE AND NUMBER OF T R U C K

STOPS

For 33 O & D Zones or Groups of Zones in Central District Source: Data drawn from P.C.C.T.S. Survey

trips and x — total floorspace in thousands of square feet] and / = I 6 I + . I O I X ( J ' = estimated number of P C C T S stops].)

The coefficient correlation of the number of O & D truck destinations and the total amount of floorspace in all nonresidential land uses, as well as the correlation between P C C T S truck stops and total floorspace, each equal .95. Each coefficient of determination is thus slightly in excess of 90 percent, or it can be said that 90 percent of the variation in the number of trucks by O & D Zones in the central district can be associated with variation in the total amount of nonresidential floorspace used.25 These theoretical equations define the relationship between truck trips and total space, undifferentiated as to use, but modulated by the space usage dispersion in the central district. On the average one can expect an increase of 340 O & D truck destinations or 101 25 T h e correlation coefficients are somewhat smaller when the calculation is performed omitting the two largest zones. For thirty-one zones and groups of zones the coefficient of correlation of the number of O & D truck destinations and total nonresidential floorspace is .82, and the correlation between P C C T S truck stops and total nonresidential floorspace is .75. T h e coefficients of determination are thus .67 and .56, respectively.

174

SELECTED

EXPLORATIONS

P C C T S truck stops, for every increase of one million square feet of space used. T h e deviations of the actual number of trucks in a given subzone from the computed number of trips based upon the amount of floorspace used can be partially explained by the distribution of space by type of use in each of the zones. W h e n the deviations, zone by zone, are plotted against the actual amount of space occupied by each type of establishment, suggestions as to the influence of each type of use on the total truck impact begin to emerge. (The scatter diagrams by separate types of establishment are not included among the illustrations of this report.) T w o general phenomena are revealed by the scatter diagrams: (1) For each of the six types of establishments there is a clustering of zones containing a small absolute amount of space in a given land use category, around the line of zero deviation; (2) for each of the six types of establishments there appears to be a more or less distinct tendency for the zones containing the larger absolute amount of space in a given land use to pull the actual number of truck stops or destinations either above or below the average. T h e heavier floorspace concentrations of manufacturing and wholesaling with stocks each reveal a tendency to correlate positively with the deviations from the basic regression line, while consumer services, wholesaling without stocks, and business services tend to correlate negatively. Retail establishments reveal no clear pattern. This may indicate that the influence of retail space is roughly the same as the combined influences of all space used, or may be the result of the mingling of central district retail shops and local convenience goods shops serving the resident population. When space used by retail and consumer services are combined, however, the larger the amount of space devoted to the combined uses, the larger the negative deviation from the regression line. T h e clustering of the zones with small amounts of space in each of the use classes is in part biased by the mode of presentation. When the absolute amount of space in a given use is low, the total space in all uses will tend to be low. While the percentage error for all space size groups is roughly the same, the absolute error in the

SELECTED EXPLORATIONS

175

smaller size groups will be smaller and consequently a congregation of smaller size groups in each use class around the line of zero deviation is to be expected. O n the other hand, when small amounts of space are involved, then it may be assumed that, by and large, establishments are of smaller size. It is suggested in Chapter V I that goods-movement systems may be divided roughly into two groups: systems common to all types of establishment and systems associated uniquely with certain kinds of establishment. In the smaller establishments the common goodsmovement systems can be expected to weigh heavily in their total and, consequently, the differentiating influence on volume of goodsmovement (as measured by truck trips or stops) of the type of establishment will be submerged. O n the basis of the crude presentation of the data this is admittedly a tortured interpretation, but it does provide a guide to the direction of future study. Similar results were found when additional calculations were made relating the average number of trucks per thousand square feet of nonresidential space to the proportion of space in each of six basic land uses in thirty-three zones or groups of zones. Six regression lines were computed for the percentage of space in a given use against the average number of trucks per thousand square feet of space. Figure 25 presents the results of these calculations. In each of the equations, the coefficient of x indicates the increase or decrease in the average number of trucks that could be attributed to an increase of 1 percent in a given use. T h e constant term represents the average number of trucks that could be expected if a given use did not exist in a given zone. Thus, as zero percentage of floorspace in each use is approached, the number of trucks in the one reflects the amalgamated influence of the remaining uses. A l l six constants are roughly equal, which merely means that although different kinds of land use exert differential influences, the effect of a land use mix of any five uses is not appreciably influenced by the introduction of a small amount of a sixth use. In terms of traffic and planning, a land use arrangement which has a variety of uses is superior to one which has segregation of uses; variety spreads the traffic burden, while segregation concentrates it.

176

SELECTED

EXPLORATIONS

1.00

10

20

30

40"

50

60

70

80

90

100

P e r c e n t of F l o o r Space in Each Land Use (x) FIGURE 2 5 . PERCENT OF FLOORSPACE IN E A C H OF SIX L A N D USES AND AVERAGE N U M B E R OF T R U C K T R I P S PER 1,000 SQUARE F E E T OF FLOORSPACE Source: D a t a d r a w n from P h i l a d e l p h i a Central District Study and O & D Survey

With more detailed data on type of destination establishment and with the accumulation of such information for a wide variety of cities, it should be possible to estimate the number of truck trips that can be expected to occur in any zone or subzone depending upon the land use composition of the area. Similar estimates can be made for any expected change in land use patterns which is indicated by collateral studies. In redevelopment studies, goods-movement, before and after, can be evaluated for the area under consideration, and the reverberations on the surrounding area, induced by the redevelopment program, can be evaluated as well. Since gross floorspace alone accounted for over go percent of the variation in the number of truck trips, one can expect that additional and more refined data will permit the forging of more efficient tools for estimation and forecasting. Summary

This chapter is devoted to selected empirical explorations into the relationships between land use and the movement of persons and goods. Some of these instances are drawn from existing studies

SELECTED EXPLORATIONS

177

in the field, and others were developed in the course of this study. Some are of interest here as illustrative of kinds of useful data and the methods for obtaining them; others suggest measures and analyses of the relation of land use and movement which may prove useful in further study of the subject. The analyses which could be attempted during this study were incidental to the major purposes: development of a conceptual framework and testing of some means of data collection. They are at best fragmentary and inconclusive, and are only a few of the many which may be made from data which are available in a number of cities.

CHAPTER

ix

Toward Improved Methods of Traffic Analysis

PRECEDING C H A P T E R S have reported an exploration of certain aspects of the nature of urban communities, particularly the relationships between their physical forms and their systems of social interaction. T h e present chapter returns to the starting point of the first chapter to ask: But what of that other ultimate goal of the study—improvement in methods of traffic analysis and forecasting? Let us inquire briefly how the variables and relationships postulated in this study may contribute to the development of these improved methods. T o be of direct assistance to the traffic engineer and city planner, the new methods of analysis should be relatively simple to apply, but should take account of foreseeable shifts in the need for traffic facilities—shifts due to the complex economic and social changes which occur in a community over several decades of time. In other words, methods yielding greater predictability are required. In the terms of this study, the need is for a method of forecasting a probable structure of movement, in specific space-time dimensions, for an urban area or for a major channel of movement, given assumptions as to the future activities to be served and the future locational pattern of land uses.1 Essentially, the urban community may be considered a "field of force," in which there is a dynamic balance among the actors (individuals and groups), their systems of interaction, and the cultural and physical environment. Obviously, in this dynamic balance, a change in any part tends to bring changes in relationships that in turn influence other parts of the structure. In this field, the systems of interaction and the cultural and physical environment function as means and conditions; initiative rests with the actors, T H E

i See Chapter III, pp. 20-21.

T O W A R D IMPROVED

ANALYSIS

179

T o be more specific, the individuals and groups of a community, engaged in various kinds of business and other social interaction, tend to form institutionalized systems of that interaction. Among the means of facilitating their affairs, physical facilities such as traffic channels are provided. T h e nature of the means the people create becomes at the same time a situation which tends to limit the nature, form, and extent of the interaction. Within this theoretical framework, the objective of urban transportation planning becomes the adjustment of movement channels (consistent with available resources) to facilitate the activities of an urban area as much as possible; and, at the same time, to reduce as much as possible the limitations which the channels may impose on growth or change in the city's activities. Operations

Research

in

Traffic

In a dynamic field of this kind, analytical methods designed to serve planning objectives must start with certain assumptions regarding one segment of the field and discover their implications in other parts of the field. Application of these methods for planning purposes, to traffic analysis in a concrete urban situation, resembles "operations research." This systematic application of research methods to practical problems has been spreading in government and industry since its initiation in England during World War II. It draws upon the knowledge and techniques of a wide variety of disciplines to determine the most effective deployment of available resources to accomplish stated ends.2 Urban traffic has never been subjected to such a systematic scrutiny. T h e methods of "operations research" which might apply have not been made clear for lack of precisely defined objectives and a relevant conceptual framework. Moreover, substantive knowledge of the relationships among urban activities, land use, and traffic is meagre due to lack of empirical research. It is not the intent of this study to develop the needed "operations research" methods. Using the conceptual framework sug2 For a general statement of the objectives and methods of "operations research" see Russell L . Ackoff, "Operations Research in Business and Industry" Industrial Quality Control VIII (May, 1952), 41-52; see also P. M. Morse and G. E. Kimball, Methods of Operations Research (New York, 1951).

i8o

TOWARD

IMPROVED

ANALYSIS

ASSUMPTIONS about Population and E c o n o m i c and Social Structure

DESIGN REQUIREMENTS for Movement Channels V

*

FIGURE 2 6 . SIMPLIFIED DIAGRAM OF PLANNING ANALYSIS PROCESS (to illustrate P r o b l e m 1 )

gested here, however, it is possible to propound a few applied traffic-analysis problems and to suggest possible directions in which methodological development may proceed. Among such problems are these: 1. T o discover design requirements for a system of movement channels intended to provide optimum service for movement of people and goods for the anticipated kind and level of activities at a given future time in an urban area (Figure 26). 2. Within a given limitation of available financial resources, to de-

TOWARD IMPROVED ANALYSIS

l8l

termine which adjustments to a system of movement channels in an urban area (among a range of possible alternatives) may be expected to produce the greatest benefit through facilitating growth or desired change in systems of interaction (e.g., trade) in the area. 3. T o construct a hypothetical structure of movement anticipated at a future time as a result of proposed adjustments to a system of movement channels, within an assumed pattern and level of activities in an urban area. 4. T o appraise the merits of proposed alternative adjustments to a system of movement channels in an urban area over a given period of time, with particular reference to facilitation of growth or desired change in systems of interaction (e.g., trade) in the area. An Analytical Model for Prediction These examples do not nearly exhaust the range of possible investigations that will be found appropriate in urban planning programs once the problems are made explicit. However, these and others may be fitted into an analytical model such as the following for Problem 1 illustrated in Figure 26. In this model the analysis starts with an assumed population and economic and social structure described in appropriate quantitative, qualitative, and relational terms. From this, on one hand, estimated systems of goods- and persons-movement are derived. It will be remembered that these systems are to be stated in quantitative terms without reference to precise location in time and space. O n the other hand, estimates are made of total land use requirements of the population and of the various economic activities assumed in the first step. T h i s estimation of quantitative land use requirements is commonly made by city planners in the preparation of land use plans. A s part of the city planning process a land use plan is made. T h i s consists of a spatial allocation of the quantified land use requirements derived previously. Finally, the land use plan and the previously estimated systems of goods- and persons-movement are combined to obtain an anticipated structure of movement, from

182

TOWARD IMPROVED ANALYSIS

which channel design requirements may be derived. Obviously, this model is greatly oversimplified. It does not include many mediating factors which must enter into each step of the process, for example: assumptions regarding technological change or the rate of adjustment in land use patterns to be expected through the operation of the real estate market, or the effect of existing channels and the feasibility of desirable channel adjustments. T o the reader with a scientific orientation, however, it must be emphasized that the process of community planning inevitably requires a series of such assumptions, the weighing of alternative probabilities and the exercise of choice of values and priorities. T h e development of methods for traffic analysis is a phase of this wider field of developing a more logically coherent planning methodology. The necessary assumptions, standards, and priorities need to be made more explicit. Required

Empirical and Methodological

Research

T o this end, needed research is of two kinds: empirical studies in a developing theoretical framework, and methodological studies to make explicit the planning process. A number of suggestions for "empirical" research have been made in earlier chapters of this report, and many others will become apparent. This will include: basic study of the urban community, its composition, structure, systems of interaction; study of the dynamics of urban land use, their origins in community structure, and the various mechanisms and limitations affecting land use change inherent in operation of the real estate market and in governmental intervention; study of the "microscopic" aspects of individual movements; study of the nature and dynamics of movement systems and their translation into specific movement structures through the mediation of temporal and spatial factors. The "methodological" research also must have an empirical basis, of course; but its focus will be on methods of application in community planning. Studies of this kind may well start with specific problems, such as those outlined above. They might take the form of model construction in hypothetical situations, or might be applications to specific urban areas, or combinations of the two.

T O W A R D IMPROVED

ANALYSIS

Inspection of the diagram in Figure 26 will show how the relationships of the various steps may be determined. For each problem various elements will become dependent or independent variables. Search will be made for the nature and action of intervening variables which would occur in each major step indicated on our simplified diagram. Methodological construction will be built upon the framework of developing theory and will be given substance by the results of the so-called "empirical" studies. The present study is but a chapter in the unfolding story of discovery that will lead to awareness of the nature of the communities of men, and will contribute to the ability of men to shape their communities better to serve their needs. Within that long-continued investigation, systematic inquiry into movement has been a largely neglected aspect. Meanwhile, it is commonly observed that cities are changing as the mobility of people and goods changes. The automobile is recognized as a major consideration when mammoth regional shopping centers are built in the far reaches of metropolitan areas near major highway intersections. Large industrial plants are built along transportation lines in rural areas, freed from the necessity of huddling in congested towns. The development of public policy and of intelligently guided public action depends upon better knowledge to be gained through research. Already enough is known to enable the practitioner of planning to improve his methods considerably; but the time has yet to come when better traffic-analysis and planning methods will be ready for widespread, practical use. They can be developed through prosecution of research and through a working relationship between the researcher and the practitioner. From this both stand to benefit.

APPENDIX

A

Methods and Procedures of the Field Investigation

R E S E A R C H UNDERTAKEN to test hypotheses already formulated has a relatively clear path before it in the selection of appropriate data to be gathered. This study, however, was exploratory in character and consequently the development of concepts and hypotheses, the appraisal of the feasibility of answering pertinent research questions, and experimentation with methods and techniques of obtaining data were concurrent objectives. A conceptual framework gradually evolved as experience was gained in field work and illustrative data were accumulated. This does not mean that no progress at all had been made on conceptualization before the start of the field investigation. Early memoranda had emphasized the need for separating the study of movement of persons and of goods, and the choice of means or manner of travel as a separate factor in traffic. Concepts of personsmovement had been formed, particularizing different kinds of trip, the varying bases of operations, and multiple destinations of individuals. T h e importance of the association of land uses in destination areas was also viewed as an influence in the amount of travel to individual establishments as destinations within those areas. T h e importance of varying characteristics of individuals who travel and of establishments had been suggested. Sufficient progress in conceptualization had not been made, however, to permit rigorous selection of the most significant kinds of data to be gathered. As a result, very early, long lists of possibly pertinent characteristics of persons, goods, vehicles, movement, and establishments were prepared (see Appendix B). Accordingly, little discrimination was possible in the design of early interview forms; they became almost dragnets, with which it was hoped to draw up

186

THE

FIELD

INVESTIGATION

some knowledge of the range of data that would be obtained at establishments. Preliminary

Qualifying

Interview

T h e first item of field work was the design and testing of a "qualifying interview" schedule for use in discovering the kinds of data available in establishments and the willingness of establishments to cooperate by giving access to company records, by allowing new records to be made, and by permitting interviews to be taken on the premises. T h e process of testing the preliminary schedule also gave the interviewer access to an establishment and enabled him to observe its operations, if only for a short time, in light of the broad purposes of the entire study. T h e instructions to the interviewer directed him to prepare a written statement after each qualifying interview in which he recorded his observations and impressions in whatever form he found suitable. Side comments of the respondent on matters not included in the questionnaire form, but relating to the purpose of the study, were also noted. These comments referred to the manner in which the establishment operated, its functions, daily activities and routines, side lines, type of customers, employees and business visitors, price lines, and any other items that served to supplement or clarify the qualifying interview, and were not self-evident from the classification of the establishment. T h e interviewer was further instructed to attempt to synthesize the data secured on the questionnaire and the salient observations culled in the course of the interview. These reports, plus the experience of the interviewers in administering the questionnaire, constituted sufficient pretest to enable the redraft and adoption of two schedules for qualifying interviews: one for establishments in which the movement of goods was to be studied, and the other for use in establishments selected for the study of the movement of persons. Qualifying

Interviews:

the

Questionnaire

T h e qualifying interview consisted of three major sections devoted to: A) data on the establishment; B) movement of persons

THE

FIELD INVESTIGATION

187

to and from the establishment; and C) shipment and receipt of goods by the establishment. Sections A and B were administered to establishments in which persons-movement was to be studied, and sections A and C were used in places where goods-movement was under consideration. SECTION A:

DATA ON

ESTABLISHMENTS

Data sought in Section A were basically related to the type and magnitude of land use by the establishment. In addition to the usual identification data, information was sought on the main function of the establishment, the specific type of goods or services sold or offered, and whether the establishment was an independent unit or part of a larger unit. T h e remaining questions in Section A of the questionnaire referred to the size of operation and the character of its land use: the amount of floor area used; type of building occupied; the amount of frontage; the amount of adjacent land occupied in conjunction with the establishment and the purposes for which it was used; rent or imputed rent; the sales volume and gross receipts; and number of employees, including active proprietors. T h e items indicating the magnitude of operations were selected from a much longer list of characteristics of establishments which were deemed pertinent to the movement of goods and persons (see Appendix B). This involved the tentative formulation of several general hypotheses, regarding the kinds of measures of size that would be readily available and would relate most closely to the varying traffic potentials associated with the different types of movement generators. T h e questionnaire itself, however, was not addressed to the testing of the hypotheses, but rather to the field problem of determining methods and processes for collecting data, so that the tests could be made at some future time when it would be possible to design and conduct a pilot study. T h e exploratory character of this study is manifest in the spread between the formulation and the test. It was quite evident that not all of the items on the tentative list could be collected. Even if it were possible, it was felt that extensive detail would impede the formulation of a lucid body of functional relationships between volume of movement and type

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and size of establishment. It was also evident that no single criterion of size would serve for all types of establishments. A warehouse and a department store occupying the same amount of space obviously have a different traffic impact. A moving-picture theater and a law firm, employing the same number of people, will have sharply different numbers of visitors in the course of a day. A steel plant and a financial institution will, of course, have a different volume of goods shipped in and out, despite the fact that their gross income may be the same in the course of a year. This was basic to the study—that various land uses exert influences of different orders on the traffic burden, even when certain measures of size are identical. It was assumed, however, that within each class of land use, variations in floorspace, number of employees, or income, either individually or in combination, would be sufficiently related to variations in the volume of traffic to enable calculations to be made of the latter on the basis of the former. How fine a classification of land use would be necessary to allow a calculation or prediction of this sort was left to the subsequent pilot study to determine. At this stage, the investigation was concerned only with the examination of a sufficiently diverse group of establishments to uncover the nature of the data-collection problems. SECTION B: DATA ON MOVEMENT OF PERSONS

Section B was addressed to establishments in which the availability of data pertaining to the movement of persons was to be studied. Three major groups of persons, whose movements related in some way to the establishment, were specified: employees of the establishment, including active proprietors; business callers; and the general public. Employees and active proprietors comprised a distinct group—persons on the payroll of the firm. In the case of eleemosynary or other types of establishments utilizing volunteer workers, persons who maintained a regular schedule of attendance were considered to fall in this group. In selecting the characteristics to be studied in relation to the movement patterns of employees, it was again necessary to select a few salient items from a larger group of characteristics which were possibly pertinent to the study of moving people. Data on age, sex,

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and marital status were held to be sufficient to permit initial study of differences in movement patterns, particularly when linked with information on the position of the employee in the establishment. In addition, special note was taken of those employees whose duties involved making trips during working hours on business of the establishment. The respondent was asked if trip records were maintained for employees whose duties involved trips on company business. Available records were checked to see whether they included information on the name of employee; his title or position; the department with which he was associated; the purpose, destination, and duration of trip; and the mode of travel. Distinguishing between visits made by the general public and those made by business callers presented some difficulties in classification. Virtually all visits involving actual or potential contractual relationships may be considered as business visits. Yet it was desirable to distinguish between the customers of a department store and the salesmen who wish to sell goods to the store, between the mother who visits a health station to obtain a free booklet on child nutrition and the printer who picked up the copy and delivered the booklet. But this distinction posed certain difficulties. A man going to his bank to make a deposit may be considered a member of the general public, but if the same man negotiates a loan, is he in this category or is he a business visitor? And if he does both things in the course of the visit, how is he to be classified? The buyer for a retail shop, making a purchase from a wholesaler or manufacturer, is on a business trip, but if he stops to purchase a package of cigarettes on his way back to the shop, he becomes a member of the general public. In the absence of a clear criterion of classification for these two groups, it was decided to make the distinction only in the case of such establishments as retail shops, theaters and museums—those that serve a large number of "customers" who could be readily identified as such. Thus, business visitors included all persons who stopped at an establishment on matters pertaining to its administration, management, or maintenance, while those who visited or came to be served

igO

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by the manifest activity of the establishment were considered to be public visitors. Since the principal purpose served by this distinction was an attempt to relate the components of traffic to the functions performed by the establishment, the distinction was made only for those cases where a large number of people was involved. It matters very little in the case of a picture-framing shop, with ten visitors in the course of a day, that two came to deliver materials or to read the electric meter. T h e record forms for business callers and the general public were designed to reveal the departments of the establishment that attracted trips for business purposes or visits by the general public, and the list of trip purposes associated with each department. Triprecord forms for business callers investigated the availability of data on the name and address of the establishment represented by the caller, his immediate origin, length of visit, and mode of travel. Since it was unlikely that more than a few establishments would maintain records of visits by the general public (and this impression was confirmed during the pretest), the respondent was asked, informally, what could be done with the existing records to secure data on public visits similar to that requested in connection with business callers. He was also asked if he would consent to a brief interview with a few visitors to his establishment provided suitable arrangements were made in advance. SECTION

c:

DATA

ON

SHIPMENT

AND R E C E I P T

OF

GOODS

T h e objective of Section C of the qualifying interview devoted to goods-movement was to determine similarly the availability of data on moving goods and a movement of goods. In the past, when data were gathered, focus had been on the vehicle. W e decided to focus on the establishment (that is, we considered the establishment as a way station in the journey of goods from the time they entered the area until they left it, or reached the ultimate consumer) and to see if collection of data were not facilitated, their quantity augmented, and their quality improved. T h e goods-movement interviewer sought to determine the availability and kind of records pertaining to the value, destination or

THE FIELD INVESTIGATION

igi

origin, mode of transportation, and number of shipments for goods received and shipped. In accordance with the subsystems associated with goods systems focused on establishments, four primary classes were designated: goods sold or for resale, goods for which service is provided, goods which have been or are intended for processing, and goods for use in repair and service rendered outside or within the establishment. T o supplement the inquiry regarding the existence of records, several substantive questions were included. These referred to the usual shipping arrangements made by the firm, including the use of vehicles other than truck for incoming or outgoing shipments, the weekly and seasonal variations in the value and type of shipments and of goods shipped. If records were maintained, the respondent was asked whether he would be willing to maintain a record of a selected group of items for a short period of time provided that the requisite forms were furnished. Experience with the Qualifying

Interviews

There were few difficulties encountered in obtaining responses to the substantive questions contained in the qualifying interview. Once the respondent had consented, he was evidently willing to answer the questions readily and even to elaborate some of the points. T h e difficulties for the most part were terminological. " T r i p " was invariably interpreted as meaning a visit away from the city, and after a few interviews the term "business visit" or "call" was used instead. Expressions such as "common carrier" and "contract carrier" frequently required explanation, which afforded the interviewer an opportunity not only to define the term but also to show the relevance of the question. Questions on the amount of gross income or monthly rent, however, generally annoyed the respondents: fifty-nine out of sixty-one refused to answer. T o forestall abrupt termination of the interview or in a few cases to avoid violence, the interviewers hastened to indicate that the reply to the question, although important, was, of course, optional. In many cases, the pressure of time caused the respondent to skip the more complicated questions or those requiring a lengthy reply.

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AVAILABILITY OF RECORDS

T h e investigation of records for data pertinent to the movement of persons and goods revealed an astonishingly low level of record keeping on the part of most establishments. It was particularly striking to find that only a few had complete personnel records. Of the thirty-two firms in which "persons interviews" were conducted, twenty-one had a record of age of employees, twenty-seven of the number of men and women workers, and only fourteen knew their marital status. O n goods received and shipped, fifteen out of twenty-nine kept records of incoming and outgoing goods, five maintained statements of incoming goods only, and nine kept no records at all. By and large, what records were maintained were rudimentary and frequently lacking in salient business notations. EXTENT OF

COOPERATION

T h e experience with this portion of the survey demonstrated that while it was relatively simple to gain access to establishments and complete the qualifying interviews, it was exceedingly difficult to achieve full-fledged cooperation, i.e., to obtain copies of existing records, or to inaugurate records for a short period of time. A total of sixty-eight establishments, representing a diverse group of firms, mostly small, were chosen for the preliminary qualifying interview. Of these, sixty-one interviews were completed successfully, and seven refused to be interviewed at all. Only twenty-four establishments of the original sixty-eight, however, agreed to cooperate further by keeping records of persons- or goods-movements associated with their establishment. But there was even further attrition. It was necessary to visit these establishments sixty-seven times in total, and at that, full cooperation was secured from only ten establishments, for an average of 2.8 subsequent visits per establishment. If the initial interviews are included, a total of 135 interviews and follow-up visits were required to secure the cooperation of ten establishments. In the qualifying interview an attempt was made to test the reaction of establishments to requests for data, without the use of col-

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lateral assistance and elaborate preparation. Since the possibility of organization and resources for the development of an elaborate promotional campaign will differ from community to community, it was important to discover what the ordinary interviewer in the ordinary situation could secure without any special entree or skills. Undoubtedly, more cooperation would have been forthcoming had the assistance of business and trade association, newspapers, letter campaigns, and contacts with business executives been elicited, as the ensuing experience in the study demonstrated. INTERVIEWING

EMPLOYEES

Data on employee trips were secured in eight establishments: a manufacturing plant employing eighty persons, a retail store with forty employees, and six smaller firms consisting of four service establishments and two wholesalers. An interviewer interrogated each of the employees concerning their trips of the previous day. Executives or proprietors were interviewed first and served to dispel any hesitation on the part of the employees. Fifteen minutes per employee were required on the average, exclusive of travel, waiting, and supervisory time, for the completion of an interview of this type. The travel records for employees consisted of two major sections, the first devoted to round trips between home and work, and the second to business trips undertaken in the course of the work day. Both sections of the questionnaires called for identifying information on the position, department, home address, age, and sex of employee. In addition, the questionnaire included trip data on mode of travel, origin and destination, location of stops en route or transfer points, name of establishment (to reveal linkages between firms), purpose of stop, and travel time. All streets traversed by foot in the course of the trip were recorded, as were transfer points when public transit was used. INTERVIEWING CALLERS

A retail specialty store, a department store, a theater, and a small consumer service establishment were selected to test the feasibility of interviewing. It was emphasized in each case that trade would not

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be disturbed, by explaining that callers would be interviewed as they left the establishment. T h e conduct of the interview survey at the department store provides an illustration of the problems and techniques used at each of the establishments. Although the method was basically similar for all four places, minor adaptations had to be made in each establishment. T r i p data for persons visiting the department store were secured by a questionnaire interrogation of a sample of all persons leaving the store. T w o field men were stationed at each entrance for a day, one to do the actual questioning, while the other took a complete count of all persons leaving the store. T h e universe from which this sample was drawn was comprised of all visitors to the establishment on the day in which the survey was conducted. T h e number of visitors on a given day will vary widely depending upon factors such as day of the week, season of year, incidence of special sales, weather, some special event that draws people to the central district but to a primary destination outside the store, and a host of chance factors. In the long run the volume of visits will vary cyclically, depending upon the physical volume of retail sales. It will reflect the long-term marketing trends in the central district, the degree of centralization or decentralization in the area, the rate of population growth, and a host of other factors. In fact, one of the ultimate major objectives of the study of the movement of persons and goods is to determine the manner in which these factors influence the volume of traffic. This survey was conducted on a Friday during the month of April. T h e weather was clear and pleasant and there were no special events either in the store or in central district which would draw an unusually large group of people into the area. T h e number and proportion of total visitors questioned varied from hour to hour, a smaller percentage being sampled during the busier times of the day. T h e total number of responses amounted to 251, or roughly one half of 1 percent of all visitors over the day. T h e sample data were inflated to total traffic count in accordance with the sampling ratios calculated for the different periods of the day. T h e management of the store cooperated fully throughout the

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FIELD INVESTIGATION

195

survey, and virtually all persons stopped consented to be interviewed. No systematic selection of respondents was employed, but account was taken of the biases discussed below. Consequently, the sample permitted certain generalizations, but the small number of the respondents limited the extent to which the detail could be carried. T h e sequence of interviews was random; upon completion of an interview the field man stopped the next person who happened to leave the store at that moment. T h e survey was taken between 10:00 A.M. and 5:30 P.M.—the business hours of the store. T h e interviewers were instructed to wait until the last visitor left the store, but not to wait for the last daytime employee to leave. As a consequence, there is an underbias in the total count and an underrepresentation of employees in the sample. Data on visits by salesmen were also underrepresented in the sample and correction was made in the estimated totals for this group on the basis of information provided by buyers in the various departments of the store. T h e purpose of the interview survey was to test the feasibility of securing information on persons-movement and to obtain some limited data on the characteristics of moving persons. T h e questionnaire was designed to elicit information on interbase trips of various types, the mode of travel (including walking), and the number, location, purpose, and relative importance of the stops made en route. In addition, information was secured on the respondent's approximate age, sex, and total family income. T h e sample interview form shows the formulation and sequence of the questions and the manner in which the data were recorded. Differences

among

Establishments

While the small firms appeared to have little objection to permitting persons to be interviewed, only a few permitted a staff member to search the company's records of goods-movement. These records, by and large, provided only fragmentary data and were not in readily usable form. Manufacturers, wholesalers, and retailers usually kept invoices on which were recorded the names and addresses of consumers or suppliers, and occasionally the commodity and its weight. Some retailers used "Firm Mailing Books" provided by the

196

THE FIELD INVESTIGATION

United States Post Office Department, which included note of shipping and postal insurance charges in addition to the receiver's name and address. Service establishments generally lacked goods records entirely. Thus, even when permission was given to abstract goods movement records, the results were unsatisfactory and the procedure costly. None of the firms interviewed would permit stationing an interviewer for a few days who would maintain records of goods-movement in a form adapted to the needs of the study. Since only small establishments were contacted at the beginning of the field work, further tests were made of the feasibility of applying the qualifying interview to larger establishments. For trial purposes, a hotel, a supermarket, and a theater were selected. These interviews revealed several differences between the large and small establishments. As a rule, it was more difficult to make the first contact with the large establishment. Arrangements were more formal. T h e appropriate executive's permission was required, usually in writing, and the time span between the initial contact and the interview was longer. But once the interviewer had secured the endorsement of the top executive, be he proprietor or manager, there was excellent cooperation in all branches of the establishment. This was essential, since the departmentalization of the larger firms made it necessary to interview more than one person in order to complete the questionnaire. Perhaps the most important distinction between the larger and smaller establishments is in management viewpoint and methods. T h e scale of operation of larger firms requires the maintenance of detailed records for operation and management. Executives of the larger firms are usually acquainted with business research and they are usually more aware of, and articulate about, their problems; consequently they are receptive to any additional information concerning their establishments. This interest provided a strong selling point of an offer to make available all results of the surveys conducted in the subject establishment. Thus, the movement study became a means of securing some research on their operations at little or no cost to the firm. Subsequent cooperation from these establishments resulted in the conduct of an interview survey with members of the general public

THE

FIELD INVESTIGATION

197

visiting the theater, a survey of personal and business trips made by employees of the supermarket, and a record of goods shipments to and from the restaurant located in the hotel. Case Studies

Favorable experiences with the use of interviewers stationed within the establishment to conduct spot surveys of persons-movement, and the interest and cooperation evinced by the larger establishments, led to experimentation with case study methods. T h e case studies differed from the type of interviews which preceded them by orienting in a general fashion toward the gathering of a substantial amount of information from a single establishment. Data collection was facilitated because of a careful prior arrangement with a top executive of each establishment. Experimental case studies were conducted in three establishments. It was believed that these cases would afford an opportunity to examine characteristic problems of the case method that might be encountered in further studies of this type. T h e establishments chosen for this phase of the study were: 1. T h e Home Office of a Large Industrial Corporation T h i s establishment, located in central Philadelphia, is the administrative office of one of the major national corporations. Over 1,300 persons are employed, and a substantial proportion of the personnel are high-ranking executives and staff officers. 2. T h e Plant of a Large Manufacturing Firm Located in the industrial northeastern section of the city, this firm employs close to 2,500 persons. Virtually all of the management and production activities of the firm are located on the site. T h e plant itself consists of many buildings and yards, and includes a parking lot for employees accomodating 300 automobiles. There is a railroad spur line on the site and a barge mooring on the Delaware River. 3. A Large Department Store This establishment is one of the largest department stores in the area carrying a full line of merchandise. It is located in the heart of downtown Philadelphia and is accessible to all public

198

THE

FIELD

INVESTIGATION

transportation. All goods shipments are loaded and unloaded directly from the street because of the lack of off-street facilities. In each case authorization for the conduct of the study was obtained from a responsible official to whom the objectives of the study were explained. He was also informed in broad fashion of the types of information desired and was promised a copy of whatever information was collected or analyzed in the course of studying the establishment. T h e details of the specific items of information were discussed with the department heads in each of the subject fields and methods of collection determined. For some items the firms agreed to undertake the collection or preparation of data, while for others it was necessary to assign an interviewer to collect or collate the required information. IMPORTANCE OF THE INTERVIEWER

T h e case study method places considerable responsibility on the interviewer, who, in effect, becomes director or coordinator of research for the case under study. As a consequence, intensive interviewer training assumes considerable importance. T h e interviewer must be familiar with the broad purposes of the study as well as the relevant detail. He must be conversant with business records and organization, and have a general familiarity with the way in which large firms do business. Although the initial contact with the subject establishment is made in advance of the first call, it is, of course, essential that the interviewer be able to sustain the interest of the respondent during their first face-to-face meeting. PRELIMINARY INFORMATION ON ESTABLISHMENTS TO BE STUDIED

In order to discuss the problem within the context of the firm under study, the interviewer attempted to familiarize himself with some of the problems of the industry or activity of which the firm is a part. He also sought information on the firm itself from published sources, such as Moody's, Poor's, Dun and Bradstreet, and the firm's annual reports to stockholders. Where organizational charts were available, they were found to be a helpful guide in asking pertinent questions about likely sources

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199

of data. When these charts could not be obtained, a hypothetical chart, which was thought to be characteristic of the firm, was developed. T h e likely functions were assumed for each department and the required data organized in conformity with the anticipated functional organization. As a further guide to the interview, tentative tables were designed which made it possible to channelize the discussion more easily. In the course of the case study, however, these were frequently modified in the light of particular circumstances. After the initial conversation with the top executive, the interviewer was directed to those operating and staff departments which were likely sources of information. These usually included personnel, payroll, accounting, building superintendent, shipping and traffic, and others, depending upon the type of establishment and its organizational structure. Here the task of the interviewer was twofold: to organize investigation for the specific types of information that could be found in the records of the firms; and to prepare, supervise, and conduct whatever sample surveys were needed to supplement the information collected from the records. Frequently, it was necessary to collect information pertaining to the same topic from several departments, and it was the interviewers' responsibility to collate the data and cross-check the results. An attempt was made to collect information on the volume and characteristics of home-to-work trips of employees, business trips made from and to the subject establishment, visits made by the general public, and the shipment and receipt of goods. Data on home-to-work trips were secured through the use of a questionnaire distributed to a sample of employees in each of the establishments. Questions concerned the location of residence, mode of travel, travel time, and parking. Data on visits made by business callers were collected by interviewers stationed at the appropriate departments. Visitors were asked the purpose of trip, mode of travel, number of stops, and the address of the previous and subsequent stop. Of the three establishments studied, the department store was the only case that presented an opportunity to investigate visits by members of the general public. Methods used to collect data have

200

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been described above. T h e establishment constituted a separate subzone in the 1947 O 8¿ D study of the Philadelphia-Camden area, and thus it was possible to compare data collected in the case study with a section of the results of the O 8c D survey. Conclusion T h e experience with the various methods of data collection indicate the difficulties inherent in accumulating sufficient information on a sample basis to implement the analysis of movement and traffic, particularly the movement of goods. Small establishments are generally unwilling, and have neither the necessary resources nor records to become voluntary respondents in a large-scale study. T h e r e appears to be, however, a sufficient number of smaller establishments that would permit intensive study of their operations and of the associated movement of persons and goods. T h e larger establishments appear to be easily accessible and cooperative, taking "the long view" and having a conversance with research records and techniques. A l t h o u g h little difficulty is anticipated in large establishments, a sample study of all establishments would be faced with the insoluble problem of an inordinate number of refusals in establishments of smaller size. Even if sufficient cooperation were forthcoming from this group, the cost of establishing records and collecting data would be prohibitive. It would appear, therefore, that a selection of case studies of a large number of representative and focal establishments of varying sizes would be a satisfactory device through which systems of movement could be constituted and analyzed. It would be necessary to integrate the findings of the case studies with O & D data, information on marketing and distribution channels, as well as the information that exists on the nature of establishments and locations, e.g., land uses and patterns of uses. T h r o u g h a synthesis of this type it should be possible to derive quantitative estimates of movement relationships and to evaluate the movement systems and the structures of which they are a part.

APPENDIX

B

Classification of Items

Pertinent to the Study of Movement

A

N E X T E N S I V E O U T L I N E of items pertinent to the relationships between persons-, goods-, and vehicles-movement and land uses was compiled as an aid in the formulation of hypotheses and a delineation of the field of interest. It soon became manifest that the outline was virtually a catalogue of urban life and that the principal purpose that it served was to provide a universe from which certain salient items could be selected. It was clear that many of the items overlapped or were intercorrelated and that some were modifying rather than determining. T o reduce the study to manageable proportions, a limited group of key items was selected for exploration and analysis. These items form a substantial part of the farmework of this study. T h e original complete list is appended on the following pages for reference purposes. ITEMS PERTINENT TO THE STUDY

OF

PERSONS-MOVEMENT

I. Moving persons A. Characteristics 1. Age 2. Sex 3. Race 4. Nationality 5. Occupation 6. Industry 7. Position in establishment (function) a. Executive b. Nonexecutive 8. Economic status 9. Locations of bases of operations a. Home b. Work

202

I T E M S IN T H E STUDY O F

MOVEMENT

I. Moving persons (continued) c. Other 10. Background a. Urban b. Rural B. Quantitative measure (number of individuals) II. Movement of persons A. General characteristics 1. Kind of trip a. Round b. Simple interbase c. Compound interbase 2. Extent of trip a. Crossing cordon line b. Within cordon line 3. Kind of base (starting and terminal) a. Residential b. Work c. School d. Other 4. Destination of trip (by leg of trip) a. Establishments b. Destination zone 1) Extent (boundaries) 2) Arrival points 3) Departure points 5. Route 6. Length of trip; of legs (physical measures) 7. Direction of trip; of leg (toward or away from kind of base) 8. Transfer points 9. Mode of transportation (type and variety of vehicles or locomotion, change in mode of travel) 10. Time of departure or arrival a. Hour b. Day c. Week of year 11. Duration of trip; of leg 12. Rhythm (departures, arrivals, trips) a. Frequency b. Regularity 13. Speed (Item 6 divided by Item 11) 14. Expenditure for movement (in dollars) B. Psychological aspects 1. Tensions or needs which stimulate person to travel

ITEMS

IN T H E

STUDY

OF

MOVEMENT

203

II. Movement of persons (continued) 2. Goal of trip (origins, nature, and determinateness at progressive stages of trip) a. Determination of goal events b. Determination of intended destinations 1) Locus of recognized potential destinations 2) Relative valences of recognized potential destinations 3) Relative valences of intermediate regions associated with potential destinations (anticipated conditions of transportation) 3. Attitude toward trip a. Condition of transportation b. Destinations c. Accomplishments; transactions C. Quantitative Measures applicable to the study of movement of persons 1. Length of trip by distance (classes ranging from 500 feet or less to 20 miles or more) 2. N u m b e r moving over various routes 3. N u m b e r of trips 4. Number of events a. Changes in mode of transportations b. Transactions 1) A t an establishment 2) W i t h i n a destination zone 3) O n a trip 5. T i m e a. T i m e of day (hour, day, week, month, year) b. Duration (hours and minutes) 6. Speed—feet or miles per hour 7. R h y t h m a. Of departures, arrivals, transactions, trips b. Frequency, regularity (e.g., transactions per unit of time) 8. Cost a. Dollars per trip b. Dollars per transaction 9. Conditions of transportation (time, cost, convenience, pleasantness; indexes, such as, number of steps to climb, distance to walk, number of changes of transportation, crowding of vehicles, traffic speed, density in street, availability of parking space) III. Transactions A . T y p e of transaction (action, experience, state of being) B. Extent of premeditation

204

I T E M S IN T H E STUDY O F

MOVEMENT

III. Transactions (continued) 1. Premeditated 2. Impulse C. Nature of business 1. Personal 2. Institutional ITEMS PERTINENT TO THE STUDY OF

GOODS-MOVEMENT

I. Moving goods A. Characteristics 1. Kind of commodity 2. Density 3. Bulk or package 4. Large or small units (locomotives or watches) 5. Physical state (liquid, gaseous, or solid) 6. Some attribute of goods denoting whether or not delivery is urgent, such as perishability, parts replacement, style goods; such items as are flown by plane 7. State of fabrication (from raw materials to finished product, ingredient for other product, etc.) 8. Value 9. Relationship to establishment a. T o serve function of establishment b. T o assist functioning of establishment B. Quantitive measures 1. Weight 2. Bulk or volume 3. Number of units 4. Number of containers 5. Number of shipments 6. Number of truckloads (define size of truck) 7. Number of railway carloads (of what kind) 8. Value of units II. Movement of goods A. Characteristics (in terms of nature of establishments at terminal points) 1. Origin a. Geographic location b. Type of establishment 2. Destination a. Geographic location b. Type of establishment 3. Nature of movement a. Independent

ITEMS

IN

THE

STUDY

OF

205

M O V E M E N T

II. Movement of goods (continued) b. In association with other goods in movement 4. Intra-urban, interurban, trans-urban 5. Length of trip (distance covered by movement) 6. Means of transportation 7. T i m e of day, week, month, year a. Starting b. Arrival c. Mid-point of trip d. Duration 8. Speed (distance per unit of time) 9. Cost of movement 10. R o u t e B. Quantitative measure x. Miles or blocks 2. Duration (hours) 3. Foot-pounds, ton-miles, per unit of time 4. Cubic feet of goods X distance I T E M S P E R T I N E N T T O THE STUDY OF V E H I C U L A R

I. M o v i n g vehicles A . Characteristics 1. K i n d of vehicle a. T r u c k 1) Light 2) Heavy b. Private auto c. Bus d. Street car e. T a x i f. Subway and elevated trains g. Railroad train h. Ferry i. Other 2. W e i g h t and size 3. K i n d of power 4. A g e and condition of vehicle 5. Load-carrying capacity 6. Availability for use a. Privately operated for private use b. Contract carrier c. C o m m o n carrier B. Quantitative measures 1. N u m b e r of vehicles

MOVEMENT

2O6

ITEMS IN THE STUDY OF

MOVEMENT

I. Moving vehicles (continued) 2. Weight 3. Volume 4. Load capacity 5. Vehicle flow at specific points II. Movement of vehicles A . Characteristics 1. T y p e of route a. Routinized 1) Rail and motor trolley 2) Bus, some types of delivery trucks, etc. b. Nonroutinized 2. Type of trip a. Continuous (direct) b. Interrupted 3. Termini a. Origin 1) Geographic location 2) Type of establishment b. Destination 1) Geographic location 2) Type of establishment 4. Length of trip 5. T i m e (starting mid-point of trip arrival) a. Hour b. Day of week c. Week of year 6. Duration of trip 7. Direction 8. Speed 9: Rhythm 10. Parking a. Location 1) Relative to destination points or area 2) Absolute b. Kind of parking facility (classifications in O 8c D) c. T i m e and duration d. Cost 11. Loading and unloading a. Kind of facility 1) Curb 2) Off-street b. T i m e and duration

ITEMS

IN

THE

STUDY

OF

M O V E M E N T

207

II. Movement of vehicles (continued) B. Quantitative measures 1. Number of vehicles 2. Number of trips 3. Vehicle miles 4. Vehicle stops 5. Cost I T E M S P E R T I N E N T T O T H E STUDY OF L A N D U S E S AS R E L A T E D TO THE M O V E M E N T OF PERSONS, G O O D S , AND V E H I C L E S

I. Information on character of establishment A. Residential establishments 1. Persons in household a. Age-sex composition b. Activities of members 1) Number employed (by occupation and/or industry) 2) Number in school c. Family roles 1) Head of household and spouse 2) Children 3) Grandparents or other relatives 4) Roomers, boarders 5) Workers in household 2. Dwelling unit a. Kind of structure 1) Detached and semidetached 2) Row houses 3) Multi-family, unserviced 4) Apartment-hotel, including maid service b. Number of rooms in dwelling unit (number of bedrooms, kitchen, dining room, living room) c. Facilities 1) Private bath and toilet 2) Full cooking 3) Installed heat d. Rental or equivalent rent 3. Tenure a. Kind (owner, renter) b. Length 4. Functions performed a. Meal preparation b. Income-producing activities 1) Principal source of income

2O8

ITEMS IN THE STUDY OF

MOVEMENT

I. Information on character of establishment (continued) 2) Auxiliary source of income c. Home-entertainment facilities (especially television) 5. Automobile (number) 6. Location a. Present location b. Reasons for choice of present location (particularly relative importance of travel considerations) c. Satisfaction with present location d. Preferred locations B. Nonresidential establishments 1. Kind of establishment a. Principal kind of business b. Ownership status (separate business, functional branch of integrated business, unit of chain, government agency, nonprofit organization) 2. Functions performed at location a. Fabrication of goods b. Assembly of goods c. Display of goods d. Sale of goods displayed (including goods displayed by sample) e. Rendering of services at location (including sale thereof) f. Instruction at location g. Rendering of services at customer location h. Sale of goods or services to be performed elsewhere i. Buying of goods or services j. Storage k. Receiving and shipping of goods 1. Receipt and dispersal of moneys m. Office work (management and facilitating functions) 3. Persons based at establishment (by age, sex, family status, occupation, or function performed) 4. Persons visiting establishment (by age, sex, family status, occupation) a. Visitors on personal business of members of the establishment b. Visitors on business related to function of the establishment 5. Size of establishment a. Compensation to persons engaged 1) Payroll 2) Other b. Gross receipts

I T E M S IN T H E STUDY O F

MOVEMENT

209

I. Information on character of establishment (continued) c. Measure appropriate to principal function 6. Space occupied by establishment a. Kind of space (ground-floor store space; other store space; space in office building, residence building, loft building, etc.) b. Floorspace occupied and used by establishment c. Floorspace vacant and under control of establishment d. Land without structure used by establishment and use thereof e. Ground-floor front footage 7. Site characteristics of establishment a. Address, subzone, census tract, Census of Business Area b. Kind of location (CBD by subareas, outlying centers, neighborhood business districts, string streets, isolated establishment) c. Geographic relation to other businesses offering competitive service to one or more of major lines carried 8. Attitude towards location II. Each unit of land A. Number and kind of establishments B. Summarization of functions performed in establishments C. Summarization of members of establishments D. Daytime population (members of establishments plus number of visitors at a given time) E. Physical intensity of land utilization 1. Gross floorspace index (ratio of total area of floorspace to area of land) 2. Net floorspace index (ratio of total floor area occupied or controlled by establishments to area of land) F. Intensity of occupancy 1. Resident population per unit of land area 2. Resident number of households per unit of land area 3. Total number of members of establishments per unit of land area 4. Daytime population per unit of land area G. Net area of land (area within boundaries of land unit) in square feet H. Site characteristics 1. Interior or corner location 2. Pedestrian volume on sidewalk of each frontage 3. Mean distance from center of frontage of this unit to arrival and departure points associated with destination zones

210

I T E M S IN T H E STUDY OF

MOVEMENT

III. Patterns and groupings of land uses A. Delineation of areas 1. Destination areas a. Types of establishments within area 1) Establishments of same type 2) Variety of types 3) Nucleation of types 4) Determining type (i.e., the existence of a type of use without which the trip would not have been made at this time to this area) 2. Groupings of establishments a. Establishments of like number or kind b. Establishments of complementary function c. Establishments having similar relationships to other places, establishments, or facilities B. Quantitative measures 1. Number of establishments by type 2. Proportion of establishments by type 3. Amount of land (or space) used by type 4. Proportion of space used by type 5. Proportion of establishments by type inside vs. outside the area

APPENDIX

C

Channels of Marketing R . S. ALEXANDER and associated authors have described typical channels of marketing. A f t e r warning of the confused pattern of practice, the frequent changes in concrete channels operative at a particular time, and the infinite variations to be observed in individual concrete channel sequences, these authors list the f o l l o w i n g types: 1. From Producer Direct to Consumer, (a) Makers of business, or industrial, goods often sell direct to using concerns, (b) Manufacturers or growers sometimes sell direct to ultimate consumers by house-to-house canvass or through their own stores. 2. From Producer to One Middleman to Consumer, (a) Manufacturers of business goods may sell to distributors (merchant middlemen) who resell to business users, (b) Makers of industrial goods may sell through agent middlemen (such as manufacturers' agents or selling agents) to using concerns, (c) Producers frequently distribute direct to retailers, who resell to ultimate consumers. Such sales may be made to large establishments (such as chain-store systems, department stores, or mailorder houses) or, through branch houses operated by the manufacturers, to smaller independent storekeepers. 3. From Producer to Wholesaler to Retailer to Ultimate Consumer. Several decades ago this was by far the most important channel through which goods moved to market. Perhaps it is so today, but its significance has declined considerably within recent years. T h e producer occasionally sells through an agent middleman (such as a selling agent or manufacturers' agent) to retailers, who resell to ultimate consumers. 4. From Producer through an Agent Middleman (such as a Broker or a Manufacturers' Agent) to Wholesaler to Retailer to Ultimate Consumer. It sometimes happens that several agent middlemen intervene consecutively at one point or another in the process.1 1R. S. Alexander, F. M. Surface, and W. Alderson, Marketing

»949). PP- 111-12.

(rev. ed.; New York,

212

CHANNELS OF

MARKETING

Ralph F. Breyer has distinguished several component kinds of channel within these generalized marketing channels. He discusses generally the "unit marketing channel," which he says "is composed of business units (performing some marketing work, of course) having a distinct business identity or name or a distinct business location, regardless of common ownership." 2 Breyer's "business units" compare with "establishments" as defined in this study. Within the unit marketing channel Breyer describes three constituent channels: (a) the selling channel, representing a chain of business units, or establishments, making effort to sell or buy; (b) the transfer channel, representing actual tranfers of title to goods; and (c) the goods channel which represents the chain of establishments and transportation media through which the goods physically pass. Obviously the last is the most significant to goodsmovement analysis. T h e study of marketing as an institutional process is relatively new and still developing; and other aspects of marketing have received more attention than channels. It seems that up to the present no extensive study has been given goods channels, particularly systems of such channels within urban localities. This can be done appropriately in connection with analysis of urban goods-movement systems, for it is essential to the understanding of their functioning. Effects of marketing channel differences will be apparent depending on the stage in the distribution process at which the goods move into and out of a particular urban area. In goods-movement analysis there can be expected subsystems of goods-movement between different kinds of merchant middlemen and urban portals and transportation points. T h e relative volume of this in-and-out movement within the total movement system may depend upon the nature of a city, and the relative importance of its wholesale and retail function compared to those of other cities. In many small cities most of the goods arriving at retailers may be expected to 2 Ralph F. Breyer, Quantitative Systemic Analysis and Control: Study No. i Channel and Channel Group Costing (Philadelphia, 1949), p. 29.

CHANNELS

OF

MARKETING

213

come from outside the city. In some important wholesale centers a large proportion of retail stocks may come from local wholesalers' or producers' warehouses, or local packagers. It seems reasonable to suppose, in the absence of actual research knowledge, that a number of basic differences among marketing channel groups will have important effects upon related systems of goods-movement. These channel differences are to be found in the nature of the middlemen in the process, the nature of the relationships among the establishments in a channel, and the nature of commodities and the markets for them. Among the characteristics of middlemen in the marketing process which may affect the operation of marketing channels, and therefore the related systems of goods-movement, the following might be found to have a bearing: (1) degree and kind of specialization of the business according to process and commodities; (2) whether middleman acts as agent or merchant; (3) whether he operates with or without stocks; (4) the nature of delivery and other services rendered; and (5) volume of business and area of operation. T h e degree of vertical integration of a marketing channel is an important characteristic of the relationships among establishments which may affect channel operation. Unified ownership or other control of all or a large part of the marketing process between producer and ultimate consumer may affect not only the interrelations of intermediate establishments but also their nature and location, and the amount, routinization and rhythm of goods movement as well. Also, if some stage of processing, such as ripening, packaging, assembling, or pasteurizing, is required locally within a marketing channel, the system of goods-movement will obviously be affected. Food distribution as an example of channel differences is cited in the following excerpts from a discussion of food marketing by Walter C. Hedden: T h e three elements . . . entering into the location and design of terminals—namely, the dominant type of inward transportation, the nature of the processing to be accorded in the city, and the degree of vertical trade integration—may be found in any market center. 3 »Walter C. Hedden, How Great Cities Are Fed (New York, 1929), p. 56.

214

CHANNELS OF

MARKETING

Food terminals and industries seek locations on inward transportation arteries. T h e location of food terminals and food industries in any terminal market is influenced more or less generally by the dominant transportation service and inherent commercial and physical characteristics of the traffic. . . . T h e relative importance of railroad, truck and steamship handling of the city food supply is of course a dominant influence in locating markets, warehouses and industries such as pasteurizing plants, meat packing establishments and poultry slaughtering houses.4 . . . location of terminals has a general aspect connected closely with the type of commodities involved and commercial methods of distribution . . . pasteurizing and bottling milk may be called an industrial process along with slaughtering of livestock, whereas distribution of fresh fruits and vegetables is solely a marketing process.5 Cutting through the primary classification of processing or simple merchandising and storage, we find the consideration of integrated commercial control vs. repeated purchase and sale within the city market. Where a single distributing organization such as a milk company or a chain store has acquired complete control from shipping point to consumer and has a system of its own warehouses or distributing stations, the food terminals required will be of the decentralized regional type, while the individual commission merchant, broker, wholesaler type of distribution will continue to demand centralized terminal markets.6 * Ibid., p. 50. 6 Ibid,., p. 52. « Ibid., p. 56.

GLOSSARY

IN THE COURSE of this study it b e c a m e necessary to e n d o w c e r t a i n w o r d s w i t h special m e a n i n g i n o r d e r to facilitate t h e discussion a n d d e v e l o p m e n t of the c o n c e p t u a l materials. T h e w o r d s listed h e r e are also d e f i n e d i n the b o d y of the text w h e r e they h a v e b e e n integ r a t e d i n t o the discussion. I n listing the terms a l p h a b e t i c a l l y , it b e c a m e necessary to separate terms that d e p e n d u p o n each other. C o n s e q u e n t l y , some definitions i n v o l v e expressions that are d e f i n e d elsewhere i n the Glossary; such expressions are italicized. Area of assembly: A n y empirically differentiated area which is the focus of systems of converging or assembling movement of people; the summation of overlapping destination areas of persons gathering at an establishment. Associated destinations: T h e establishments or other destinations visited by an individual in the course of a trip. Base of operations: A n establishment of which an individual is a functioning member. It is the place where he resides, is regularly employed, conducts business, attends school, or customarily and regularly performs other activities. A n individual may thus have more than one base of operations. Channels of movement: T h e physical facilities involved in the movement of persons and goods. These include highways, streets, public transit lines, stations, vehicles, terminals, as well as facilities for parking, loading and unloading, and transfer. Convenience goods: Standardized commodities which are needed frequently and are characteristically purchased at the most convenient location. Desire lines: Straight lines drawn on a map connecting and summarizing the origin and destination of trips. Desire-line technique is usually used to present graphically the data collected in origin and destination surveys. Destination: A n establishment, unit of land, area or other location within which a transaction occurs. It may be precisely designated as in the case of destination point or establishment, or more generally differentiated as in the case of destination area. Destination area: T h e smallest area which will enclose all destination points (and the routes of trip legs between them) visited between the

2l6

GLOSSARY

time an individual leaves and boards a vehicle, between a base and a vehicle, or between starting and terminal bases where no vehicle is used. This represents the "walking distance" within which transactions occur. Arrival point of destination area is a point at which an individual leaves the last vehicle carrying him toward a destination area (e.g., a trolley or subway stop, a place where a car is parked); or a base from which an individual walks to a destination area. Departure point of destination area is a point at which an individual boards a vehicle carrying him from a destination area, or a base to which an individual walks from a destination area. Destination establishment: An establishment within which a transaction occurs. Destination point: A precisely definable location, including an establishment, land unit, or other place where a transaction occurs. Determinateness of goal: The degree of definiteness with which the goal of a trip is perceived. The goal of a trip may have various degrees of determinateness in regard to the goal event and intended destination. Establishment: An individual or group occupying a recognizable place of business, residence, government, or assembly within or upon a continuous site. One or more establishments may occupy such a unit of land. (Where two or more establishments occupy a single structure or unit of land, any parts of the structure or areas of land used by the establishments in common, such as washrooms and lobbies, are considered parts of each establishment.) Event: An action, experience, or state of being which occurs in a given segment of space and time in the course of a trip. Events significant to this study are either transactions or changes in transportation. Goal area: A geographic area within which an individual hopes or intends to accomplish a goal event; a relatively undifferentiated intended destination. Goal event: An objective of travel. A desired or intended action, experience or state of being expected to take place as the result of travel in a given segment of time and space. Goal of trip: The objective of travel. It consists of one or more goal events and one or more intended destinations. Intended destination: The place at which a goal event is expected to occur. Interbase movement: Movement between two of an individual's bases of operations, such as home and work, home and school, school and work, or the reverse of these; or between two bases of the same kind, as between a judge's chamber and his private law office. (One of the bases may be outside an urban area under study.) A major group of systems of movement is designated "interbase movement." Land use (urban): The nature of activities customarily engaged in by

GLOSSARY

2 17

an establishment or establishments occupying a unit of land, and the major purposes (or activities) to which public areas of land are devoted. Categories of land use should not be confused with categories of buildings. Classification by type of building tends to obscure the variety of establishments and activities that may be housed in a given structure. Linkage: A relationship between establishments characterized by continuing or frequently recurring interaction. Linkage leads to the movement of persons and goods between linked establishments and generates a tendency on the part of establishments so related to seek proximate locations or locations that are mutually accessible. Origin and destination survey: A traffic-study technique through which data are secured on origins and destinations of movements of persons, goods, or vehicles, together with various characteristics of the persons, goods, vehicles, and the movements involved. Potential destination: A location or locality at or within which an individual believes that a goal event can occur, and which is considered by an individual in the choice of an intended destination. Rhythm: Frequency or regularity, or a combination of the two, applied to any characteristic of movement. Round-trip movement: Movement from a base of operations to one or more destinations (none of which are bases for the moving individual), and return to the starting base. Some of these movements may be from bases within the urban area to destinations either within or without the urban area. Others may be from bases outside the urban area to destinations, at least one of which is within the urban area. A major group of systems of movement is designated "round-trip movement." Route of trip: The summation of all points occupied by an individual or any vehicle in which a person is traveling during the course of a establishment. trip, except within a destination Shopping goods: Goods for which individuals characteristically wish to compare style, quality, or price before purchasing. Specialty goods: Goods which a purchaser is willing to undergo some inconvenience to obtain, e.g., goods for which he is willing to make a special trip. Structure of movement: The spatial and temporal manifestation of movement at a specific time and place. One may describe the structure of movement within a particular land area, along a street or other movement channel, or the structure resulting from a system of movement at a particular time among specifically located establishments. Among the pertinent properties of a system of movement are volume, distance traveled, time, rhythm, density, kinds of trips, purpose of trip, and kinds of destinations.

218

GLOSSARY

Systems of movement: Broad patterns of movement that are functionally related to organized systems of business or other social action, without regard to concrete time or location. The daily movement of persons from home to work, or the movement of goods in the total marketing process including production, distribution, and consumption, are examples of movement systems. Through movement: A major group of systems of movement consisting of movement originating and terminating at different points outside the urban area, but passing through it. One or more destinations may be within the urban area. Traffic: Vehicles in motion, or temporarily prevented from moving. Traffic flow diagram: A graphic presentation on a map of the number of vehicle or pedestrian movements along each street and the number and nature of all turning movements at each intersection. Volume of traffic is indicated by width of line or by numerals. Transaction: An event of significance to an individual during the course of a trip, which satisfies or releases a tension in the person. A transaction may be an event hoped for or intended previously (see goal event) which is called a premeditated transaction, or may occur because a new situation in which an individual finds himself offers both stimulus and opportunity (suddenly finding a "bargain," meeting and having a drink with a friend), which is called an impulse transaction. A transaction does not necesarily occur in an establishment. The location may be a street corner, or along a route if the transaction consists of taking a walk or "enjoying a ride to cool off." Transfer point: A stop or break point in a trip at which an individual changes from one means of locomotion to another. A transfer point is not considered a destination. Trip:1 A movement of an individual by any means of locomotion between departure from a base and arrival at the same or another of his bases. A trip may be interrupted by stops or breaks at destinations (points where transactions occur) or at transfer points (where change in means or agent of locomotion occurs), in which case a trip is divided into parts, called legs. Trip, direction of: Direction of an interbase trip, or any leg of such a trip, is characterized by nature of the starting and terminal bases; direction of a leg of a round trip is said to be away from or toward the base. Trip, legs of: Parts or sections into which a trip is divided by stops or breaks at destinations (points at which transactions occur) and transfer points (where change in manner or means of locomotion occurs). i A "trip" as defined for purposes of this study differs from the definition in the standard O & D survey. The latter corresponds to "leg of trip" as used in this study except that the O & D technique does not include walking "trips" or "legs of trips."

GLOSSARY

219

Trip, length of: Physical distance traveled in the course of a trip (or of a leg) by any means of locomotion, but not including distance within a destination establishment. Trip, round: A trip beginning and ending at the same base. Trip, simple interbase: A trip between two bases without intermediate stops at a destination. It may include intermediate stops at transfer points, thus being divided into legs. Trip, compound interbase: A trip between two bases which is divided into legs by one or more stops at destinations. Valence of potential channel: Degree of relative attraction or repulsion of a channel of movement to an individual anticipating a trip, in view of his expectations regarding the conditions—time, expense, convenience or amenity—of using that channel. Valence represents a summation of the anticipated attractive and repulsive qualities of a potential channel to one individual at one moment and in one situation. Valence of potential destination: Degree of attraction or repulsion to an individual of a potential destination, representing a summation of the attractive and repulsive qualities. The valence may be positive or negative. Valence of a location applies only to one person at one moment and in one situation.

INDEX

Accessibility, how achieved, 107; term, 108, 118, 119; changing patterns, 131 Accommodation, term, 118 Action, systems of, 17 Action processes, persons-movement systems based on, 61 f „ 87; goods-movement systems based on, 91, 93-100; classified, 103 Activities, institutionalized into procedures, 13; systems of urban, 17; differential growth rates and changes in aggregate, 122-27 Actual event, defined, 46 Alderson, W., R. S. Alexander, and F. M. Surface, 211 n Alderson, Wroe; quoted, 71, 74, 102; ratios suggested by, 144-54; paired linkage factor, 150 f.; group-linkage factor, 152 ff.; application of the ratios, 1547' Alderson and Sessions, 76, 83, 1 4 m , 143, 170 n Allen County, Ind., traffic study, 140 Ancillary land uses, 112 Area of assembly, 24-29; defined, 47, 215; persons-movement systems related to, 83-87; number and nature of trips to, 84 ff.; assembly-area profiles, with figs., 156-69; comparative traffic ratios for three business establishments, tab., 154 Area of dispersion, 2g Assembly movement, 21 Assembly, point of: area of: see Area of assembly Associated destinations, defined, 58, 215 Baldamus, W. and P. S. Florence, 98, 111 n Base of operations concept, 62, 63; defined, 39, 215, 216 Bases, of round and interbase trips, 219 Blankenship, A . B., & Associates, Inc., 170« Breese, Gerald W., 64, 139 Breyer, Ralph F., on marketing channels, 212 Buildings, construction of new, 127

Bureau of Public Roads, internal and external origin and destination traffic survey developed by, 9 f., 135 (see entries under O & D survey); R . A . O A . classification, 101 Business services, type of land use, 115, " 7 . 125 California Department of Highways, 30 Callers at establishments, 18g; interviewing of, 193 ff. Carroll, J. Douglas, Jr., quoted, 8on Case studies, in field investigation, 197200; importance of the interviewer, 198; preliminary information on establishments to be studied, 198 ff. Cedar Rapids, la., study of personsmovement in, 70 ff., 76, 86, 143 f. Chamberlin, E. H „ quoted, 109 Channel, valence of potential, defined, 55. 219 Channels of marketing, see Marketing Channels of movement, see Movement, channels of Chicago, central business district, 64; Medical Center, 78; land values in Loop district, iogn Cities, physical structure: patterns of relationship, 13; systems of activities, 17; changes in social roles and bases of operations, 63; intercity travel, 96 f.; land values in N.Y. and other, 109« Civil Aeronautics Administration, 96 Codominant land use, 112 Commodity, goods-movement systems based on kind of; classification, 100-102 Compatible land uses, 113 Compound interbase trip, defined, 40 Connecticut Highway Department, 12« Construction, maintenance, and repair: goods-movement incident to, 95 Construction, new, 127 f. Consumer services, as land use type, 115, >«7 Consumption goods-movement incident to, 95

222 Convenience goods, defined, 215 Cox, Reavis, panel method developed by, 76; study of Philadelphia dispersion market, 141 Daytime-population studies, 137-39 Denver, Colo., Civic Center, 78 Desire lines, 9, 29, 31; defined, 215 Destination, defined, 44, 46, 215; valence of potential, defined, 55, 2ig Destination and origin, see under Origin Destination area, defined, 47, 51, 215; figs. 47, 48; extent, 51-53 Destination distance, 51 ff. Destination establishment, defined, 46, 216 Destination points, 215; defined, 46, 216 Determinateness of goal, defined, 216 Dispersion, area of, 29 Dispersive movement, 22 Distance inputs, l i o n Distance weights, application of, 163 ff. Distribution, goods-movement systems incident to, 98-100 District of Columbia, traffic flow, fig., 30 Dominant land use, 111 Dwellings, see Residence Dynamic relationships of movement systems, 118 ff. Employees, travel records: interviewing of, 188, 193 Engineer, problems of city planner and, 10, 61 Equipment, goods-movement incident to,

95 Establishments, as units of land use, 14, 16; defined, 14, 38, 216; locational requirements, 16; movement affected by locational pattern of, 17, 104-18; four factors, 18; difference in definitions, 37; elements necessary to, 38; their members, 38 f.; persons-movement systems related to kind of area or, 62 ff., 69-83; factors of linkage and relationship, 66; residential, 69 ff.; school, 77; other nonresidential, 77 if.; grading according to social role, 82; major categories, 90 f.; goods-movement systems based on kind of, 90-93; processing and packaging, 97; linkage and proximity, 110; dominant and subordinate uses, 111; six basic land use types of nonresidential, 115; types of functional area, n 6 f . ; chang-

INDEX ing movement requirements, 119 ff.; external relationships among, 120; changes in activities of, at a given location, 122; differential growth rates and changes in aggregate activities, 122-27; land use change as result of growth and attrition, 124; studies at nonresidential, 139 ff.; paired-linkage factor, 150 ff.; list of characteristics pertinent to movement of goods and persons, 187, 201-10; differences among, 195 ff.; preliminary information on those to be studied, 198 ff. Event, defined, 216 Field investigation, methods and procedures, 185-200; preliminary qualifying interview, 186; questionnaire, 186-91; experience with qualifying interviews, igi-95; differences among establishments, 195-97; case studies, 197-200 Firms, relocation of, 121 f. Floorspace, correlation between, and truck impact, 171 ff., figs., 172 f., 176 Floorspace density, 164 ff. Florence, P. Sargant and W . Baldamus, 98, 11 in Flow in systems of movement, 29 f. Food distribution, 100, 213 t. Forecasting, see Predictability Fort Wayne, Ind., persons-movement in, 70 ff.; traffic study, 140 f., 143, 144 Friction of space, 108-10, 117 Functional area of establishments, 116 f. Glossary, 215-19 (see also 37-59 passim) Goal area, defined, 53, 216 Goal event, defined, 45, 216 Goal events and destinations, 44-51 Goal of trip, defined, 216 Goals, determinateness, 53 ft., 216 Goods-handling, trend from, to personshandling, 126 Goods-movement systems, 88-103; usually one-directional, 22; by truck, 88, 89, 92 f. (see also T r u c k trips); difference between persons-movement and, 8g; three major orders, 89; based on kind of establishment, 90 ff.; on process of action, 93 ff., 103; on kind of commodity, 100 ff.; relationship between land use and, 134-77; data on, 136; items pertinent to study of, 204 f. Goods-persons ratio, 147 ff.

INDEX Group-linkage factor, 15s ff. Growth rates, differential, and changes in aggregate activities, 122-27 Haig, Robert Murray, quoted, 108, 117 Hedden, Walter C., on food marketing, 100, 213 f. Highway, three stages of planning, 4 ff. Hoover, Edgar M., quoted, 108, 12371 Households, relocation of, 121 f. Impulse transaction, 46; defined, 218 Incompatible land uses, 113 Individual movements, 31 f. Individuals, activities institutionalized into procedures, 13; see also Persons Individuals and establishments in action, >6 Intended destinations, 45; defined, 58, 216 Interaction, see Action processes Interbase movement, defined, 39, 216; systems of, 62, 63-65; travel between home and work the largest segment of, 64 Interbase trip, 44; definitions, 40, 219; see also T r i p Interviews, qualifying, see Qualifying interviews Investigation, field, see Field investigation Isard, Walter, 11 on Journey-to-work studies, 64, 137-39 L a n d use, traffic problems and, in city planning, 3-12; trends, and guidance of change, 3-6; major concerns of the planner, 4; highway plans must be coordinated with plans for, 4; planning, guidance, and control of change in pattern of, 7; meanings, 13, 37, 216; relating of, to traffic, 13-19: changing nature, 13 f.; change in urban patterns: three major steps in process, 14 f.; establishments as units, 14, 16; components of, 16; influence of movement on patterns of, 104-33 ( s e e a ' i 0 Movement); pattern illustrated by study of central district of Philadelphia, 115-18 (see also Philadelphia); two groups of forces that lead to changes, 118; dynamic relationships of movement systems, 118 ff.; major processes through which change comes about, 121 ff.; street system a basic element in, 129;

22$ relating movement of persons and goods to, 134-77; traffic analysis methods, 135-37; selected measures and relationships, 144-55; assembly-area profiles, with tab. and figs., 156-69; relationship between truck trips and, 169-76; six basic categories, 1 7 m ; items pertinent to study of, as related to movement of persons, goods, and vehicles, 207 ff. Land use characteristics, term, 147 Land values in N.Y. and other cities, iogn Liepmann, Kate K., on journey-to-work studies, 64, 137 f. Linkage, defined, 111, 217 Linkage and proximity, 110-15, 1 2 0 L i n n County, Iowa, study of travel habits in, 69, 76, 143 f. Locational role of movement, 105-8 Manufacturing, basic type of land use, 115, 116, 120 Marketing, goods-movement within, 93, 94, 95, 97 f.; channels, 98 ff., 211-14; generalized types, 211; component kinds, 212 Mass movement, forms of, 20, 21-23, 35; temporal pattern, 32-35, figs., 33 f. Member of an establishment, defined, 38 Merton, Robert K.., quoted, 57 Methodology, toward improved traffic analysis and forecasting, 178-83; research, 182 f. Minimization of movement, site efficiency as measured by, 145 ff. Mode of travel, movement based on time and, 34 f., 42 f. Motivations of travel, study of, 54 ff. Movement, influence of, on land use patterns, 104-33; locational role, 105-8; changing requirements, 119-21; variations in kind and volume of, 130, 131; selected measures and relationships, 144 ff.; classification of items pertinent to study of, 187, 201-10; persons-movement, 201 ff.; goods-movement, 204; vehicular movement, 205 ff.; items pertinent to study of land uses, 207 ff. channels of: defined, 37, 215; changes in street system and other, 129-32 structure of, forms of mass movement, 20, 21-23, 35; characteristics and measures, 20-36; spatial, 23-31; temporal, 31-35; defined, 37, 214, 217; com-

224 Movement (Continued) ponents: i n d i v i d u a l movements of people, 37-59; see also Persons-movement systems o f , f u n c t i o n a l l y organized; operate w i t h i n structure of m o v e m e n t , s i ; defined, 21, 37, a 18; relation to location of establishments, 104-18; friction of space, 108-10; d y n a m i c relationships, 118 ff.; a m a j o r g r o u p designated r o u n d - t r i p m o v e m e n t , 217; pertinent properties, 317; see also Goods-movem e n t systems; Persons-movement systems M o v e m e n t potential, 84 N e w Y o r k City, l a n d value trends, i o g n ; g a r m e n t center, 1 1 1 ; linked or p r o x i mate establishments, 112, 113 N o n c o m p l e m e n t a r y l a n d uses, 112 Nonresidential establishments, personsm o v e m e n t systems to, 77-83 Operations research in traffic, 179-81, fig. 180 O r i g i n a n d destination traffic surveys, 8; developed by B u r e a u of P u b l i c R o a d s , 9 f.; see also O & D surveys O & D surveys, 40 f., 42, 58, 84«, 85,86, 89, 200; " i n t e r n a l and e x t e r n a l origin a n d destination traffic survey," 8, 9 f.; p u b lications in w h i c h m e t h o d described, 9«; California's variant of, 30; use of w o r d trip, 37,40«, 7371, 2i8n; trip destination, 44; f o r P o r t l a n d , Ore., 72 ff.; analysis of trip data from, 76; a standa r d technique, 135; data drawn f r o m T r u c k R e p o r t , 170 ft.; desire-line techn i q u e , 215; defined, 217; see also Philadelphia Paired-linkage factor, 150 ff. P a n e l m e t h o d , of research, 76; of recordi n g travel, 142 f., 144 P a r k i n g studies, 136 £. Parsons, T a l c o t t , q u o t e d , 56 f. P C C T S (Philadelphia Central City T r u c k Survey), 170«; data drawn f r o m , 171 ff. Persons-handling, trend f r o m goodsh a n d l i n g to, 126 Persons-movement systems, 60-87, 139-44; components of m o v e m e n t structures, 37-59; establishments and their members, 38 f.; trips: varieties and characteristics, 39-53: determinateness of

INDEX goals, 53 ft.; roles i n w h i c h p e o p l e travel, 56 if.; based u p o n processes of action, 61 f.; u p o n k i n d of trip, 62 ff.; related to k i n d of establishment or area, 69 ff.; C e d a r R a p i d s study, 70 ff.; 76, 86, 143 f.; Fort W a y n e study, 70 ff., 140 f.; related to areas of assembly, 83 ff.; difference between goods-movement a n d , 89; relationship between land use a n d , 134-77; data o n ' 135; P h i l a d e l p h i a dispersion market, 141 ff.; data sought in q u a l i f y i n g interview: types of persons, 188 ff.; items pertinent to study o f , 201 ff. Persons-space ratios, 81 P h i l a d e l p h i a , Port R i c h m o n d industrial area, 24, fig. 26 P h i l a d e l p h i a - C a m d e n area, traffic survey, 24. 33- 83> figs-> 25. 33 f P h i l a d e l p h i a Central City T r u c k Survey, ( P C C T S ) , 17071; data d r a w n f r o m , 171 ff. P h i l a d e l p h i a C e n t r a l District Study prepared by Alderson a n d Sessions for C i t y P l a n n i n g Commission, 83, 92, 93, 115, 126, 151, 170«; areas of assembly, 24, 26, 40 ft., figs., 25, 27 f.; interview surveys, 47 ft., figs. 48, tabs. 49 f.; study of work-base establishments in, 78 ft., 85; change in activities, 123 f.; a p p l i c a t i o n of the A l d e r s o n ratios, 154 ff.; case studies of field investigation, 197 ft. P h i l a d e l p h i a City P l a n n i n g Commission, 83, 86, 125, 170n P h i l a d e l p h i a dispersion m a r k e t study, 71, 74, 76, 141, 144 P h i l a d e l p h i a O r i g i n and Destination Survey, 170 P l a n n i n g , h i g h w a y and transportation channel plans a specialized p a r t of total city p l a n n i n g , 4; three stages, 4 ff.; i n f o r m a t i o n needed, 4, 6; methods of traffic survey a n d analysis available for, 8; i m p r o v e d methods of traffic analysis a n d forecasting, 178-83; objective of u r b a n transportation p l a n n i n g , 179 Portland, Ore., O & D survey, 72 ff. Port of N e w York A u t h o r i t y , 10 Port R i c h m o n d industrial area in Philad e l p h i a , 24, fig. 26 Potential destination, defined, 55, 217 Pratt, Charles O., 137 Predictability, 54; approaches to p r o b l e m of, 12; key to, 87; toward i m p r o v e d

INDEX methods of traffic analysis and forecasting, 178-83; analytical model for, 181; fig., 180 Premeditated transaction, 46; defined, 218 Procedures for securing data, testing of, 134 Processes of action, see Action processes Processing or packaging, goods-movement incident to, 94; establishments, 97 Production, goods-movement incident to, 97 f.; shift away from, 123 Profiles, analyzing of assembly areas by means of, 156-69, with figs. Proximity and linkage, 110-15, 120 Psychological analysis of travel motivations, 54 ff., 76 Purpose of trip, 61; term, 44, 58; use of term in O & D studies, 73« Qualifying interviews, preliminary, 186; questionnaire, 186-91; data on establishments, 187 f.; on movement of persons, 188 ff.; on shipment and receipt of goods, 190 f.; experience with, 191 ff.; availability of records: extent of cooperation, 192; interviewing employees, 193; interviewing callers, 193 ff. R a n d o m movement, 22 Ratcliff, Richard U., quoted, 14771 Ratios, pairs developed by Alderson, 14454; application of the ratios, 154-71; see also Measures Redevelopment, 128 f. Relationships, of individuals and groups, 13; within establishments, 104; see also Establishments Research, three avenues for, in systems of round-trip movement, 76; characteristics of round-trip movement to areas of assembly: methods suggested, 85 ff.; on goods-movement related to kinds of establishment, 92; operations research, 179; empirical and methodological, 182 f. Residence, separation of place of work and, 63; movement between, 64 f.; changes in place of residence, 121 Residential establishments and areas, persons-movement systems, 69-77 Residential mobility, 75 Retailing, 115, 117, 119 R h y t h m , defined, 217 Rhythms of movement, 32

225 Role, defined, 56 Roles in which people travel, 56-58, 66 Rossi, Peter H., 75 R o u n d trip, defined, 40; directions of a leg of, 218 Round-trip movement, 39, 217; systems of persons-movement, 63, 65-68; three kinds, 66 f.; avenues for research in systems of, 76 Route of trip, defined, 217 Routes of movement, 29-31 Sacramento area, traffic survey, 30 f., fig. 3° Satellite land use, 112 School establishments, movement systems, 77 Sessions, Alderson and, see entries under Alderson Shopping centers, regional, 183 Shopping goods, defined, 217 Site efficiency as measured by minimization of movement, 145 ff. Site rentals, cost of transportation and, 108 f., 1 ion Space, friction of, 108-10, 117; changes in available supply, 127-29 Spatial characteristics of structure of movement, 23-31; areas of assembly and dispersion, 24-29; routes of movement, 29-31 Specialty goods, defined, 217 Spengler, Edwin H., quoted, 10971 Status, defined, 56 Stegmaier, Joseph T . , J. T . T h o m p s o n and, 136 Street system, changes in other movement channels and, 129-32 Structure of movement, see Movement, structure of Subordinate land use, 111 Surface, F. M., R . S. Alexander, and W . Alderson, 21 in Survey and analysis of traffic available for planning, 8; O & D method, 9 f. Systems of action, 17 Systems of movement, see Movement, systems of Techniques for securing data, testing of, >34 T e m p o r a l characteristics of structure of movement, 31-35; individual, 31 f.; mass, 32-35, figs., 33 f.

226 Terminal base, 216 Terms, definitions, 37-59 passim, 215-19 Thompson, J. Trueman, and J. T . Stegmaier, 136 T h r o u g h movement, persons-movement systems, 63, 68; defined, 218 Traffic, problems of, and land use, in city planning, 3-12; regulation and control, 6, 7; dealing with, at three levels, 6f., 12; survey and analysis, 7-11; provision and improvement of physical channels of movement: planning, guidance, and control of change in the pattern of land uses, 7; relating land use to, 13-19; nature of, 16; defined, 16, 218; components in analysis of, 17; structure, 18; analysis methods, 135-37; origin and destination survey: data on persons-movement, 135; on goods-movement, 136; parking studies, 136 t.; planning improved methods of analysis, 178-83; operations research, 179-81, fig., 180 Traffic A u d i t Bureau, Inc., traffic study in Cedar Rapids, la., 70 ff., 76, 143 f.; traffic study in Fort W a y n e and environs, 70 ff., 140 f., 143, 144 Traffic-burden index, 149 Traffic-characteristic ratio, 148 f. Traffic flow diagram, 29, fig. 30; defined, 218 Traffic ratios, comparative, for three business establishments, tab., 154 Transaction, defined, 46, 218 Transfer point, defined, 218 Transit facilities, effect upon land values, îogre T r a v e l motivation, study of, 54 ff. T r a v e l patterns and records, 141 ff.; forms used, 142 T r a v e l time, mode of transportation and, 34 f-. 4« fTransportation, plans for highways and, a specialized part of total city planning,

INDEX 4; three stages, 4 ff.; most important and difficult problems of planning for, 6; mode of, and travel time, 42 f.; variations in use of facilities in personsmovement studies, 73; cost and site rentals, 108 f., 110n, 118 T r i p desire chart, 30 Trips, movement based on time and purpose, 33, 35; mode of transportation and travel time, 34 (., 42 f.; meanings used in this study and by others, 37, 39; definitions, 39, 218, 219; their varieties and characteristics, 39-53; legs of, 40, 215, 218; type of, and number of stops, 43 f.; purposes, 44-51; extent of destination areas, 51-53; study of travel motivation, 54 ff.; persons-movement systems based upon kind of, 62-68; three avenues for research, 76 T r u c k trips, goods-movement by, 88, 89, 92 f.; relationship between, and land use, 169-76; data for analysis, 170; O 8c D T r u c k Report, 170; correlation between floorspace and truck impact, 171 ff., figs. 172 f., 176

Urban portals, 93; defined, 68n Valence, of potential destination: of potential channel: definitions, 55, 219 Vehicular flow diagrams, 30 Vehicles, items pertinent to study of movement of, 205 ff. Virtual movement concept, 147 Visitors, see Callers W a l k i n g distance, 46, 51; defined, 216 Waste disposal and salvage, goods-movement incident to, 95 Wholesaling, 115, 116, 117, 119, 123 t., 125 Wolff, Reinhold P., 71 Work-base establishments, 78 ff.