The density of urban development in the United States today averages about one tenth of that historically prevalent in the Western world. This low density is both the consequence and the cause of the nation’s dependence on the automobile. Public transit, measured in passenger miles, now accounts for only about 4 percent of all mechanized urban travel in the nation. Close to half of this transit travel is confined to the tri-state New York Region.
There are three major arguments against this degree of dependence on the auto. First, it restricts the mobility of those who for reasons of health, age, or income cannot use an auto: even in the United States, half the population is not licensed to drive, and one in five households do not own an auto. Second, it causes inordinate energy consumption and is environmentally destructive: movement in groups, rather than individually, is on the whole more conservative of energy and materials and of the by-products which their use emits into the environment. Third, the downtowns of the nation’s larger cities simply lack the pace to accommodate all travel by auto at an acceptable cost, and so do inner city residential areas.
These social, environmental, and economic arguments have gained wide acceptance. A variety of efforts have been launched to make public transit more appealing—with lower fares, more frequent and faster service, better amenities, and new technology. Such improvements do indeed attract new riders, both those who previously did not make the trips, and those who previously travelled by auto. Yet improved service has rarely succeeded in increasing transit ridership by more than 50 to 100 percent. Thus, even if a 50 percent increase in public transit use were to be attained nationwide, it would reduce total automobile use in urban areas barely more than 1 percent. Of course, localized impact in the areas served could be much greater.