Accessibility in Social-Equity Evaluation

Abstract

This chapter argues that because the concept of accessibility enables comparison of transportation's benefits among social groups, it is essential to proper evaluation of the social-equity impacts of transportation decisions. Unlike mobility metrics, which tend to focus on the performance of infrastructure, accessibility metrics are readily analyzed with regard to specific groups of people, such as low-income and racial-minority groups. One group that deserves special attention in equity analysis is people without access to an automobile, because the travel modes available to individuals are the single most decisive factor in determining whether they can reach destinations. However, because accessibility is inherently multidimensional and more complex than standard mobility-based metrics, several methodological considerations are essential for meaningful analysis; considering differences in mode alone is not sufficient. The influence of mode on accessibility tends to vary systematically in metropolitan space, and accessibility analysis must consider the effect of mode and location simultaneously. The chapter then explains the mobility nature of current equity evaluation, and proposes and demonstrates the use of accessibility-based equity-evaluation tools.