ABSTRACT
Urban transportation is included in this book partly as an example of public investment in long-lived infrastructure, and partly to provide evidence of the wide range of alternatives available for dealing with externalities such as traffic congestion.2 Of course, congestion is not the only negative externality that arises from the automobile. Others include air and noise pollution, human and nonhuman death and injury, the segmentation of neighborhoods, and the disposal of old vehicles (junk yards). Despite these social harms, the automobile has become the dominant form of transportation in many countries, particularly in North America and Australia. One reason why this trend is unlikely to be reversed in autodominated societies is that employment and housing have scattered across far wider areas than in nations where mass transit still dominates urban transportation.
