| This dissertation begins with the premise that the unequal distribution of access to opportunities within an urban area stems from the interplay between three distinct sources of inequality of access: facility location inequality, which arises purely as a function of the location of the facilities to which access is measured; modal inequality, which arises from the differences between various modes of transportation; and system inequality, which is a function of the configuration of the transportation system.;A methodology is developed that disaggregates and evaluates the extent of the three sources of inequality. The method uses value-by-area cartograms to represent the spatial distribution of access. It is argued that cartograms, by shrinking and expanding the space of the more conventional map, help exhibit the affective dimension of the space of access to opportunities. To evaluate the pre-Metro degree of inequality of access to shopping and health care opportunities, the methodology is applied to a case study of the one-hundred square mile core of the Washington metropolitan area. The case study also examines the impact of the twelve-billion dollar investment in the Metro system on that inequality.;The pre-Metro patterns show significant modal inequality of access to both sets of opportunities: the transportation disadvantaged facing travel times two-and-one-half to three times as great as automobile users. For the pre-Metro transportation modes--highway, walking, and transit--the degree of system inequality varies significantly: public transit exhibits the greatest degree of system inequality, while the highway system reveals the least. However, the highway system appears biased against the more disadvantaged half of the city, reinforcing the considerable facility location and modal inequality.;The Metro system amplifies the existing inequality, rendering the transit user even more inaccessible in 1990. The transportation disadvantaged groups, because of their dependence on public transportation, obviously bear the brunt of the change. |
