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Environmental Impacts



Rationales for the development of rapid transit systems in recent decades have been based largely on reducing the adverse effects of overreliance on the automobile. These adverse effects of the auto and its associated roadway facilities have been substantially environmental. Highest in priority are urban air quality and global upper-atmosphere equilibrium, but other concerns include the destruction of homes, neighborhoods, jobs, and other valued urban places, as well as natural habitats and environments, for the construction of freeways and other large-scale facilities.

Further effects of the auto itself include noise, vibration, visual blight, and intrusion, as well as excessive energy use. Dependence on the automobile has also been a major force in urban sprawl, with freeway construction encouraging scattered low-density residential development in suburban areas.

Transit, in one form or another, has often been seen as a means of minimizing such environmental consequences. It is reasoned to do so by reducing auto traffic (particularly commute traffic) generally and avoiding further construction of urban freeways, at the same time encouraging more intensive activity at transit-oriented nodes. In so doing, it is hoped that transit might particularly help to reduce suburban sprawl and strengthen the centers of older cities, now increasingly congested and difficult to reach by car. Transit is also seen as more energy efficient and less polluting than the automobile on a per trip basis. Implicit in these objectives is a vision of transit as a contributor to the humane city.
Published in Public Transportation, ed. George E. Gray and Lester A. Hoel, 2nd edition, chapter 20.