Urban Transportation Planning In the United States: An Historical Overview: Fifth Edition

Chapter 3. Beginnings of Urban Transportation Planning

During World War II, regular highway programs stopped. Highway materials and personnel were used to build access roads for war production and military needs. With rationing of gasoline and tires, and no new automobiles being manufactured, the use of transit mushroomed. Between 1941 and 1946, transit ridership grew by 65 percent to an all-time high of 23.4 billion trips annually (American Public Transit Association, 1995). (Figure 2)

Figure 2 - Major Trends of Transit Ridership

Transit Ridership, 1900-1990

When the war came to an end, the pent-up demand for homes and automobiles ushered in the suburban boom era. Automobile production jumped from a mere 70,000 in 1945 to 2.1 million in 1946, 3.5 million, and 3.5 million in 1947. Highway travel reached its prewar peak by 1946 and began to climb at 6 percent per year that was to continue for decades (Dept. of Transportation, 1979a). Transit use, on the other hand, declined at about the same rate it had increased during the war. By 1953, there were fewer than 14 billion transit trips annually (Transportation Research Board, 1987).

The nation's highways were in poor shape to handle this increasing load of traffic. Little had been done during the war to improve the highways and wartime traffic had exacerbated their condition. Moreover, the growth of development in the suburbs occurred where highways did not have the capacity to carry the resulting traffic. Suburban traffic quickly overwhelmed the existing two-lane formerly rural roads (Dept. of Transportation, 1979a). Transit facilities, too, experienced significant wear and tear during the war from extended use and deferred maintenance. This resulted in deterioration in transit's physical plant by war's end. Pent-up wage demands of transit employees were met causing nearly a 50 percent in average fares by 1950. This further contributed to a decline in ridership. These factors combined to cause serious financial problems for many transit companies (Transportation Research Board, 1987).

The postwar era concentrated on dealing with the problems resulting from suburban growth and resulting from the return to a peacetime economy. Many of the planning activities which had to be deferred during the war resumed with renewed vigor.

Federal-Aid Highway Act of 1944

The Federal-Aid Highway Act of 1944 was passed in anticipation of the transition to a postwar economy and to prepare for the expected growth in traffic. The act significantly increased the funds authorized for federal-aid highway programs from $137,500 in 1942 and 1943, no funds in 1944 and 1945, to $500,000 annually for 1946 through 1948. The act also recognized the growing complexity of the highway program.

The original 7 percent federal-aid highway program was renamed the Federal-aid Primary system, and selection by the states of a Federal-aid Secondary system of farm-to-market and feeder roads was authorized. Federal-aid funding was authorized in three parts, known as the "ABC" program with 45 percent for the Primary system, 30 percent for the Secondary system, and 25 percent for Urban extensions of the Primary and Secondary systems.

The act continued the allocation of funds by means of formulas. For the Primary system, funds were allocated using area, total population, and postal route miles as factors. For the Secondary system, the same formula was used except that rural population was substituted for total population. For the urban extensions, Urban population was the only factor. For the first time, federal-aid funds up to one-third the cost could be used to acquire right-of-way.

A National System of Interstate Highways of 40,000 miles was authorized. The routes were selected by the states with BPR approval. However, but no special funds were provided to build the system beyond regular federal-aid authorizations.

Early Urban Travel Surveys

Most urban areas did not begin urban travel surveys until 1944. It was during that year the Federal-Aid Highway Act authorized the expenditure of funds on urban extensions of the federal-aid primary and secondary highway systems. Until that time there was a lack of information on urban travel which could be used for the planning of highway facilities. In fact, no comprehensive survey methods had been developed that could provide the required information. Because of the complex nature of urban street systems and the shifting of travel from route to route, traffic volumes were not a satisfactory guide to needed improvements. A study of the origins and destinations of trips and the basic factors affecting travel was needed (Holmes and Lynch, 1957).

The method developed to meet this need was the home-interview origin- destination survey. Household members were interviewed to obtain information on the number, purpose, mode, origin, and destination of all trips made on a particular day. These urban travel surveys were used in the planning of highway facilities, particularly expressway systems, and in determining design features. The U.S. Bureau of Public Roads published the first, Manual of Procedures for Home Interview Traffic Studies, in 1944 (U.S. Dept. of Commerce, 1944). Figure 3 shows the internal trip report form from a home interview survey. In 1944, the interviewing technique was used in Tulsa, Little Rock, New Orleans, Kansas City, Memphis, Savannah, and Lincoln.

Figure 3 - Internal Trip Report Form from a Home Interview Survey

Other elements of the urban transportation planning process were also being developed and applied in pioneering traffic planning studies. New concepts and techniques were being generated and refined in such areas as traffic counting, highway inventories and classification, highway capacity, pavement condition studies, cost estimating and system planning. The first attempt to meld many of these elements into an urban transportation planning process was in the Cleveland Regional Area Traffic Study in 1927, which was sponsored by the U.S. Bureau of Public Roads. But, even in this study, traffic forecasting was a crude art using basically linear projections (Cron, 1975b).

In the Boston Transportation Study, a rudimentary form of the gravity model was applied to forecast traffic in 1926 but the technique was not used in other areas. In fact, the 1930s saw little advancement in the techniques of urban transportation planning. It was during this period that the methodology of highway needs and financial studies was developed and expanded (U.S. Dept. of Transportation, 1979a).

By the 1940s it was apparent that if certain relationships between land use and travel could be measured, these relationships could be used as a means to project future travel. It remained for the development of the computer, with its ability to process large masses of data from these surveys, to permit estimation of these relationships between travel, land use, and other factors. The first major test using this approach to develop future highway plans was during the early 1950s in San Juan, Puerto Rico, and in Detroit (Silver and Stowers, 1964; Detroit Metropolitan Area Traffic Study, 1955/6).

Early Transit Planning

During this period, transit planning was being carried out by operators as part of the regular activities of operating a transit system. Federal assistance was not available for planning or construction, and little federal interest existed in transit. However, financial problems increased as transit ridership declined and there were no funds available to rehabilitate facilities and equipment. In some urban areas, transit authorities were created to take over and operate the transit system. The Chicago Transit Authority and the Metropolitan Transit Authority in Boston were created in 1947, and the New York City Transit Authority in 1955.

It was at this time that the San Francisco Bay area began planning for a regional rapid transit system. In 1956, the Rapid Transit Commission proposed a 123 mile system in a five-county area. As a result of this study, the Bay Area Transit District (BARTD) was formed within the five counties. BARTD completed the planning for the transit system and conducted preliminary engineering and financial studies. In November 1962, the voters approved a bond issue to build a three-county, 75-mile system, totally with local funds (Homburger, 1967).

Dawn of Analytical Methods

Prior to the early 1950s, the results of early origin-destination studies were used primarily for describing existing travel patterns, usually in the form of trip origins and destinations and by "desire lines," indicating schematically the major spatial distribution of trips. Future urban travel volumes were developed by extending the past traffic growth rate into the future, merely an extrapolation technique. Some transportation studies used no projections of any sort and emphasized only the alleviation of existing traffic problems (U.S. Dept. of Transportation, 1967b).

Beginning in the early 1950s, new ideas and techniques were being rapidly generated for application in urban transportation planning. In 1950, the Highway Research Board published Route Selection and Traffic Assignment (Campbell, 1950), which was a compendium of correspondence summarizing practices in identifying traffic desire lines and linking origin-destination pairs. By the mid 1950s, Thomas Fratar at the Cleveland Transportation Study developed a computer method for distributing future origin-destination travel data using growth factors. In 1956 the Eno Foundation for Highway Traffic Control published Highway Traffic Estimation (Schmidt and Campbell, 1956), which documented the state of the art and highlighted the Fratar technique.

During this period the U.S. Bureau of Public Roads (BPR) sponsored a study on traffic generation at Columbia University, which was conducted by Robert Mitchell and Chester Rapkin. It was directed at improving the understanding of the relationship between travel and land use through empirical methods and included both persons and goods movement. Mitchell and Rapkin state as a major premise of their study:

"Despite the considerable amount of attention given in various countries to movement between place of residence and place of work, the subject has not been given the special emphasis suggested here; that is, to view trips between home and workplace as a "system of movement," changes in which may be related to land use change and to other changes in related systems of urban action or in the social structure" (Mitchell and Rapkin, 1954, Page 65).

They demonstrated an early understanding of many of the variables that effect travel patterns and behavior; for example:

"Systems of round trips from places of residence vary with the sex composition and age of the individual members of the household. The travel patterns of single individuals, young married couples, families with young children, and households consisting of aging persons all show marked differences in travel behavior" (Ibid., page 70).

They also anticipated the contribution of social science methods to the understanding of travel behavior:

"However, inquiry into the motivations of travel and their correspondence with both behavior and the actual events which are consequences of travel would make great contributions to understanding why this behavior occurs, and thus to increase the possibility of predicting behavior" (Ibid., Page 54).

They concluded with a framework for analyzing travel patterns that included developing analytical relationships for land use and travel and then forecasting them as the basis for designing future transportation requirements.

AASHO Manual on User Benefit Analysis

Toward the end of the 1940s, the AASHO Committee on Planning and Design Policies, with the assistance of BPR, undertook the development of generally applicable analytical techniques for performing economic analysis of highway projects. The work grew out of a survey of state highway departments on the use of economic analysis which found a definite lack of similarity in the such procedures and their use (American Association of State Highway Officials, 1960).

Building upon earlier work on highway economic analysis, the committee developed a manual for conducting benefit - cost analyses (American Association of State Highway Officials, 1952b). The basic tenet of the manual was "...that a profit should be returned on an investment applies as well to highway projects as to general business ventures." Unlike previous methods of analysis which only measured construction, right of way, and maintenance costs, the manual included the costs to the user of the highway as a necessary and integral part of the economic analysis. Up to the publication, no data existed to perform such an analysis.

The manual defined the benefit to cost ratio as the difference in road user costs (between alternate routes) divided by the difference in costs. Road user costs included: fuel, other operating costs (i.e. oil, tires, maintenance, depreciation), time value, comfort and convenience, vehicle ownership costs, and safety. The value of time was specified at $1.35 per vehicle hour or $0.75 per person hour. The value of comfort and convenience was included as an increasing cost for greater interference with the trip and varying according to the type of road. It ranged from 0 cents per mile for the best conditions to 1.0 cents per mile for the worst conditions. The manual included tables and charts containing specific values for these components of costs and benefits, and the procedures to conduct benefit - cost analyses.

The manual was updated in 1960 with the same analytical methodology but new unit cost data (American Association of State Highway Officials, 1960). A major update of the manual was issued in 1977 after a number of research efforts had been completed on analytical techniques and unit cost data (American Association of State Highway Officials, 1978). The manual was also expanded to address bus transit improvements. The manual recognized that benefit-cost analysis was only an element in the evaluation of transportation projects and that it fit within the larger urban transportation planning process.

Breakthroughs in Analytical Techniques

The first breakthrough in using an analytical technique for travel forecasting came in 1955 with the publication of a paper entitled, "A General Theory of Traffic Movement," by Alan M. Voorhees (Voorhees, 1956). Voorhees advanced the gravity model as the means to link land use with urban traffic flows. Research had been proceeding for a number of years on a gravity theory for human interaction. Previously, the gravity analogy had been applied by sociologists and geographers to explain population movements. Voorhees used origin-destination survey data with driving time as the measure of spatial separation and estimated the exponents for a three-trip purpose gravity model. Others conducting similar studies soon corroborated these results (U.S. Dept. of Commerce, 1963a).

Another breakthrough soon followed in the area of traffic assignment. The primary difficulty in traffic assignment was evaluating the driver's choice of route between the origin and destination. Earl Campbell of the Highway Research Board proposed an "S" curve, which related the percent usage of a particular facility to a travel-time ratio. A number of empirical studies were undertaken to evaluate the theory using diversion of traffic to new expressways from arterial streets. From these studies, the American Association of State Highway Officials published a standard traffic diversion curve in, "A Basis for Estimating Traffic Diversion to New Highways in Urban Areas," in 1952. (Figure 4) However, traffic assignment was still largely a mechanical process requiring judgment (U.S. Dept. of Commerce, 1964).

Then in 1957 two papers were presented that discussed a minimum impedance algorithm for networks. One was titled, "The Shortest Path Through a Maze," by Edward F. Moore, and the second was, "The Shortest Route Problem," by George B. Danzig. With such an algorithm, travel could then be assigned to minimum time paths using newly developed computers. The staff of the Chicago Area Transportation Study under Dr. J. Douglas Carroll, Jr. finally developed and refined computer programs that allowed the assignment of traffic for the entire Chicago region (U.S. Dept. of Commerce, 1964).

Figure 4 - Traffic Diversion Curves for Uran Arterial Highways

National Committee on Urban Transportation

While highway departments were placing major emphasis on arterial routes, city street congestion was steadily worsening. It was in this atmosphere that the Committee on Urban Transportation was created in 1954. Its purpose was, "to help cities do a better job of transportation planning through systematic collection of basic facts ... to afford the public the best possible transportation at the least possible cost and aid in accomplishing desirable goals of urban renewal and sound urban growth" (National Committee, 1958-59).

The committee was composed of experts in a wide range of fields, representing federal, state, and city governments, transit, and other interests. It developed a guidebook, Better Transportation for Your City (National Committee, 1958-59), designed to help local officials establish an orderly program of urban transportation planning. It was supplemented by a series of 17 procedure manuals describing techniques for planning highway, transit, and terminal improvements. The guidebook and manuals received national recognition. Even though the guidebook was primarily intended for the attention of local officials, it stressed the need for cooperative action, full communication between professionals and decisionmakers, and the development of transportation systems in keeping with the broad objectives of community development. It provided, for the first time, fully documented procedures for systematic transportation planning.

Housing Act of 1954

An important cornerstone of the federal policy concerning urban planning was Section 701 of the Housing Act of 1954. The act demonstrated congressional concern with urban problems and recognition of the urban planning process as an appropriate approach to dealing with such problems. Section 701 authorized the provision of federal planning assistance to state planning agencies, cities, and other municipalities having a population of less than 50,000 persons and, after further amendments, to metropolitan and regional planning agencies (Washington Center, 1970).

The intent of the act was to encourage an orderly process of urban planning to address the problems associated with urban growth and the formulation of local plans and policies. The act indicated that planning should occur on a region-wide basis within the framework of comprehensive planning.

Pioneering Urban Transportation Studies

The developments in analytical methodology began to be applied in pioneering urban transportation studies in the late 1940s and during the 1950s. Before these studies, urban transportation planning was based on existing travel demands or on travel forecasts using uniform growth factors applied on an areawide basis.

The San Juan, Puerto Rico, transportation study begun in 1948, was one of the earliest to use a trip generation approach to forecast trips. Trip generation rates were developed for a series of land-use categories stratified by general location, crude intensity measures and type of activity. These rates were applied, with some modifications, to the projected land use plan (Silver and Stowers, 1964).

The Detroit Metropolitan Area Traffic Study (DMATS) put together all the elements of an urban transportation study for the first time. It was conducted from 1953 to 1955 under Executive Director Dr. J. Douglas Carroll, Jr. The DMATS staff developed trip generation rates by land use category for each zone. Future trips were estimated from a land use forecast. The trip distribution model was a variant of the gravity model with airline distance as the factor to measure travel friction. Traffic assignment was carried out with speed and distance ratio curves. Much of the work was done by hand with the aid of tabulating machines for some of the calculations. Benefit/cost ratios were used to evaluate the major elements of the expressway network (Detroit Metropolitan Area Traffic Study, 1955/1956; Silver and Stowers, 1964; Creighton, 1970).

In 1955 the Chicago Area Transportation Study (CATS) began under the direction of Dr. J. Douglas Carroll, Jr. It set the standard for future urban transportation studies. The lessons learned in Detroit were applied in Chicago with greater sophistication. CATS used the basic six-step procedure pioneered in Detroit: data collection, forecasts, goal formulation, preparation of network proposals, testing of proposals, and evaluation of proposals. Transportation networks were developed to serve travel generated by projected land-use patterns. They were tested using systems analysis considering the effect of each facility on other facilities in the network. Networks were evaluated based on economic efficiency - the maximum amount of travel carried at the least cost. CATS used trip generation, trip distribution, modal split, and traffic assignment models for travel forecasting. A simple land-use forecasting procedure was employed to forecast future land-use and activity patterns. The CATS staff made major advances in the use of the computer in travel forecasting (Chicago Area Transportation Study, 1959/1962; Swerdloff and Stowers, 1966; Wells, et. al., 1970).

Other transportation studies followed including the Washington Area Traffic Study in 1955, the Baltimore Transportation Study in 1957, the Pittsburgh Area Transportation Study (PATS) in 1958, the Hartford Area Traffic Study in 1958, and the Penn-Jersey (Philadelphia) Transportation Study in 1959. All of these studies were transportation planning on a new scale. They were region-wide, multidisciplinary undertakings involving large full-time staffs. Urban transportation studies were carried out by ad hoc organizations with separate policy committees. They were not directly connected to any unit of government. Generally, these urban transportation studies were established for a limited time period with the objective of producing a plan and reporting on it. Such undertakings would have been impossible before the availability of computers (Creighton, 1970).

The resulting plans were heavily oriented to regional highway networks based primarily on the criteria of economic costs and benefits. Transit was given secondary consideration. New facilities were evaluated against traffic engineering improvements. Little consideration was given to regulatory or pricing approaches, or new technologies (Wells, et.al., 1970).

These pioneering urban transportation studies set the content and tone for future studies. They provided the basis for the federal guidelines that were issued in the following decade.

Federal-Aid Highway Act of 1956

During this early period in the development of urban transportation planning came the Federal-Aid Highway Act of 1956. The act launched the largest public works program yet undertaken: construction of the National System of Interstate and Defense Highways. The act was the culmination of two decades of studies and negotiation. As a result of the Interregional Highways report, Congress had adopted a National System of Interstate Highways not to exceed 40,000 miles in the Federal-Aid Highway Act of 1944. However, money was not authorized for construction of the system. Based on the recommendations of the U.S. Bureau of Public Roads and the Department of Defense, a 37,700-mile system was adopted in 1947. (Figure 5) This network consisted primarily of the most heavily traveled routes of the Federal-Aid Primary System. The remaining 2,300 miles were reserved for additional radials, bypass-loops, and circumferential routes in and adjacent to urban areas. Studies of urban area needs were made by the states with the cooperation and aid of city officials. The urban connections were formally designated in 1955 (U.S. Dept. of Commerce, 1957).

Figure 5 - The "National System of Interstate Highways" as designated on August 2, 1947.

Funds were appropriated by then, but at very low levels: $25 million annually for 1952 and 1953 with a 50 percent federal share, and $175 million annually for 1954 and beyond with a 60 percent federal share. To secure a significant increase in funding, a major national lobbying effort was launched in 1952 by the Highway Users Conference under the title, "Project Adequate Roads." President Eisenhower appointed a national advisory committee under General Lucius D. Clay, which produced a report, A Ten-Year National Highway Program, in 1955. It recommended building a 37,000-mile Interstate System using bonds to fund the $23 billion cost (Kuehn, 1976).

Finally, with the Federal-Aid Highway Act of 1956, construction of the National System of Interstate and Defense Highways shifted into high gear. The act increased the authorized system extent to 41,000 miles. This system was planned to link 90 percent of the cities with populations of 50,000 or greater and many smaller cities and towns. The act also authorized the expenditure of $24.8 billion in 13 fiscal years from 1957 to 1969 at a 90 percent federal share. The act provided construction standards and maximum sizes and weights of vehicles that could operate on the system. The system was to be completed by 1972 (Kuehn, 1976).

The companion Highway Revenue Act of 1956 increased federal taxes on gasoline and other motor fuels and excise taxes on tires and established new taxes on retreaded tires and a weight tax on heavy trucks and buses. It created the Highway Trust Fund to receive the tax revenue which was dedicated solely for highway purposes. This provision broke with a long-standing congressional precedent not to earmark taxes for specific authorized purposes (U.S. Dept. of Commerce, 1957).

These acts have had a profound effect on urban areas. They established an assured funding source for highways, through user charges, at a time when federal funds were not available for mass transportation. They set a 90 percent federal share which was far above the existing 50 percent share for other federal-aid highways. About 20 percent of the system mileage was designated as urban to provide alternative interstate service into, through, and around urban areas. These provisions dominated urban transportation planning for years to come and eventually caused the development of countervailing forces to balance the urban highway program.

Sagamore Conference on Highways and Urban Development

The availability of large amounts of funds from the 1956 Act brought immediate response to develop action programs. To encourage the cooperative development of highway plans and programs, a conference was held in 1958 in the Sagamore Center at Syracuse University (Sagamore, 1958).

The conference focused on the need to conduct the planning of urban transportation, including public transportation, on a region-wide, comprehensive basis in a manner that supported the orderly development of the urban areas. The conference report recognized that urban transportation plans should be evaluated through a grand accounting of benefits and costs that included both user and nonuser impacts.

The conference recommendations were endorsed and their implementation urged, but progress was slow. The larger urban areas were carrying out pioneering urban transportation studies, the most noteworthy being the CATS. But few of the smaller urban areas had begun planning studies due to the lack of capable staff to perform urban transportation planning.

To encourage smaller areas to begin planning efforts, the American Municipal Association, the American Association of State Highway Officials, and the National Association of County Officials jointly launched a program in early 1962 to describe and explain how to carry out urban transportation planning. This program was initially directed at urban areas under 250,000 in population (Holmes, 1973).

Housing Act of 1961

The first piece of federal legislation to deal explicitly with urban mass transportation was the Housing Act of 1961. This act was passed largely as a result of the growing financial difficulties with commuter rail services. The act inaugurated a small, low-interest loan program for acquisitions and capital improvements for mass transit systems and a demonstration program (Washington Center, 1970).

The act also contained a provision for making federal planning assistance available for "preparation of comprehensive urban transportation surveys, studies, and plans to aid in solving problems of traffic congestion, facilitating the circulation of people and goods on metropolitan and other urban areas and reducing transportation needs." The act permitted federal aid to "facilitate comprehensive planning for urban development, including coordinated transportation systems, on a continuing basis." These provisions of the act amended the Section 701 planning program that was created by the Housing Act of 1954.