Introduction to the Special Issue on Methodological Issues in Accessibility Measures with Possible Policy Implications

Fundamental to urban and regional transportation analysis is the concept of accessibility. Because of the increasing complexity of transportation systems and their impact on our quality of life, accessibility-based ideas must become an integral part of transportation planning and evaluation. Although accessibility has been studied for a long time and there are various perspectives in its definition and measurement, it is fundamentally concerned with the opportunity that an individual at a given location possesses to participate in a particular activity or set of activities.

The objective of this special issue of the Journal of Transportation and Statistics is to facilitate a discussion on the issues involved in making accessibility-based considerations a routine part of transportation planning and evaluation. The measurement of accessibility has a rich, substantive history in the urban and regional sciences. But, except for assessing the impacts of the transportation system on special groups and for special purposes, planners and policymakers have not routinely and continuously evaluated urban systems on the basis of accessibility. However, as transportation planners are increasingly called on to address a variety of social, economic, and environmental considerations beyond historical mobility-based considerations, accessibility measures must be developed and disseminated to practitioners to enhance planning practices and improve policy evaluations. Further, the development of data and software to estimate these measures will tremendously expedite this shift in planning practices.

The papers in this special issue reflect the diverse considerations that must be taken into account in developing means to measure accessibility. Some of the papers address conceptual issues in defining and measuring accessibility, some target the development of applications tools, while others focus on empirical examples of accessibility measures.

As accessibility-based planning approaches take hold, the need for continued research and development in this area will increase. It is our hope that the publication of this special issue will raise awareness of the need to mainstream accessibility-based measures in planning and policy analysis and evaluation.

Piyushimita (Vonu) Thakuriah
Guest Editor
University of Illinois at Chicago