Competition with the Automobile
The expansion of the automobile market from the 1920's onward broke the monopoly relationship of rail transport and urban development. No other mode of travel could match the efficiencies of the automobile, primarily in terms of shorter trips and greater trip flexibility. Considered the travel mode of the future, new urban and suburban development began to orient itself around the automobile, a trend that has continued to this day.
As the auto-oriented sections of urban and suburban areas have grown dramatically since the Second World War, transit has been compelled to extend its operations into areas laid out not to maximize transit ridership, but rather to facilitate efficient automobile circulation. Transit during this time labored under the further financial burden, inherited from the free-market years of the early 20th century, of financing itself in the absence of comparable levels of municipal and federal assistance available for the creation and maintenance of auto infrastructure. This led to a considerable reduction in transit service as early as the 1940's.
Urban regions that experienced the bulk of their development after the auto revolution tend to have segregated land uses separated by barriers to anything but automobile circulation. Development around the automobile has resulted in a type of urban form that now makes other mobility options inconvenient and often uneconomical.
It was in this context that Boris S. Pushkarev and Jeffrey M. Zupan observed that the most effective way to restrain auto use is to design urban environments that make the cost and inconvenience of using a car prohibitive. Such environments already exist in the hearts of older American cities built before the advent of the automobile, where the density of land uses reduces dependence on automobiles, while increasing the relative cost of their operation. "Only as auto access becomes difficult do riders by choice begin to switch to transit."