Changing intra-metropolitan accessibility in the US: Evidence from Atlanta

The U.S. federal government appears committed to the idea of performance measurement. The Intermodal Surface Transportation Efficiency Act (1991), provides an opportunity to change the focus of metropolitan transportation planning and policy from fostering mobility (more travel) to increasing accessibility (greater potential for desired interaction), which is widely viewed as a:desirable objective among planners and the general public. This paper does three things: (1) defines the concept and clarifies questions of measurement, (2) reviews the,literature to identify important issues associated with changing accessibility, including accessibility's relationship to land use and value, poverty and unemployment, race, energy use and air pollution, (3) reports results from a case study of change in gravity-accessibility to employment by automobile, in Atlanta, between 1980 and 1990. Other authors have argued that accessibility has been increasing overtime, as well as becoming more homogenous in U.S. metropolitan areas. Together these developments are thought to have reduced its policy importance. This case study illustrates that;this was not entirely the case in Atlanta in the late 1980s. Overall accessibility declined at the end of the decade,rather than continuing its steady increase, and its influence on residential density at the tract level (the access-density gradient) also changed direction. However, accessibility's explanatory power did decline from 1980 to 1990 in Atlanta; as expected. It seems likely therefore that accessibility will continue to be valuable as an indicator of metropolitan transportation systems' performance,as well as allowing planners to better anticipate change and to be more aware of its consequences. (C) 1998 Elsevier Science Ltd. All rights reserved.