Accountability Through Accessibility: Measuring What Matters for Departments of Transportation

Abstract

To accurately measure the impacts generated by the actions of Departments of Transportation (DOTs), changes to land use and land value that result from changes to the transportation network must be included. We argue in this paper for the use of Accessibility measures in system performance and project prioritization for DOTs, to fully account for DOT decisions. Accessibility, or measurement of how easily people can connect to their desired destinations, is not a new concept, yet progress has been slow in adopting measures which focus on people rather than vehicle movement and delay. To spur further consideration of Accessibility, we document the theoretical and practical basis for Accessibility, describe available data, explore change in metrics over short and long time scales, and recommend approaches for inclusion into DOT decision making. Ultimately the full impact of DOT actions cannot be fully captured by the vehicle movement metrics which comprise the status quo. Accessibility metrics offer a way to evaluate what DOTs are providing, where, and to whom, in terms of connection to destinations and changes in land use.