Changing Lanes: Visions and Histories of Urban Freeways

4. Postwar Urban Freeways: Scaling Up for a City on Wheels, 1946–1956

4 Postwar Urban Freeways: Scaling Up for a City on Wheels, 1946–1956 From Concepts to Construction Between 1946 and 1956, the freeway planning concepts worked out during the late 1930s and the war years were elaborated, expanded, and applied to particular cities. As state highway engineers, aided by the Bureau of Public Roads, assumed control of freeway planning and construction in urban areas, design for traffic service and high-speed safety overshadowed earlier proposals to weave expressways into the fabric of the existing city and combine the new highways with mass transit. Parkway ideals receded as engineers sized new urban freeways for growing volumes of motor vehicles.1 City planners expressed some misgivings about wholesale commitment to large urban freeway systems and devised some imaginative proposals for mixtures of freeways and transit, but most accepted the new freeways as beneficial improvements. Architects wove freeways into their schemes for rebuilt central cities, often using multilevel strategies to mitigate impacts and preserve pedestrian space, but they stood outside the freeway planning system and had little effect. Although the freeway plans prepared by city planners during the late 1940s were intrusive enough, these plans did preserve some elements of the parkway tradition of the 1930s, such as limited widths, heavy landscaping , transit medians, and design speeds below 50 mph. There was some attempt to coordinate arterials with land-use patterns, redevelopment activities, and transit planning. However, this more moderate thread of freeway planning doctrine eventually faded under the pressure of mounting traffic volumes and the institutional might of the highway community. 74 Chapter 4 Preparing a New Generation of Freeway Plans for American Cities, 1946–1950 Between 1945 and 1947, the Bureau of Public Roads and the state highway departments worked out tentative routes for the interstate system. In 1947, they agreed upon 37,700 miles of the 40,000-mile system specified in the legislation, and an official map was published.2 Approximately 2,900 miles ran through urban areas. Routes for the remaining 2,300 miles of the system were not specified at this time; these miles would be devoted to urban circumferential and distributing routes, to be designated at a later date after more detailed urban transportation studies.3 The urban freeway corridors roughed out during the mid-1940s were not based on sophisticated city planning studies. Alan Altshuler has described the highway planning process as it occurred in Minneapolis–St. Paul in his classic text, The City Planning Process.4 The Highway Department’s engineers had relied on their knowledge of existing desire lines. To estimate future traffic, they had simply projected vehicle registration trends. . . . To the extent that these data were insufficient, they had relied on their engineering experience and common sense.5 But these early corridor decisions displayed remarkable durability, in spite of their weak analytical base. Their authors acquired a vested interest in their correctness and deflected demands for reappraisal and change. Placed on planning and engineering maps, they began to influence subsequent decisions about urban development. The engineers’ hurriedly prepared freeway plans of 1945–1947 proved somewhat premature because money for construction was not forthcoming . Powerful political and bureaucratic obstacles prevented the shift from rural to urban freeway building that the 1944 legislation had seemed to promise. Although “cities” were supposed to receive 25 percent of the funds, “most rural-dominated state highway departments funneled the funds to fringe locations and small towns.”6 This delay gave the state highway departments time to conduct more thorough analyses of traffic patterns. Minneapolis–St. Paul conducted a full-scale origin–destination study in 1949. But as Altshuler relates, the engineers “were unworried about the possibility that they might have located the freeway routes erroneously in 1945-46. They expected, indeed, that the 1949 survey would provide irrefutable proof that their route choices had been the best possible.”7 Highway engineers wanted accurate land-use forecasts to predict future vehicle trips, but not even major cities like Minneapolis and St. Paul had such information. The engineers Postwar Urban Freeways 75 made do with rough estimates provided by the region’s municipalities.8 Although opposed by St. Paul’s chief planning engineer, the state highway department’s proposed route locations were approved by the city in 1947. Similar events occurred in other large American cities.9 The role of freeways in shaping future urban development went largely unexamined, obscured by a narrow focus on traffic service...