Developing a comprehensive u.s. transit accessibility database

This paper discusses the development of a national public transit job accessibility evaluation framework, focusing on lessons learned, data source evaluation and selection, calculation methodology, and examples of accessibility evaluation results. The accessibility evaluation framework described here builds on methods developed in earlier projects, extended for use on a national scale and at the Census block level. Application on a national scale involves assembling and processing a comprehensive national database of public transit network topology and travel times. This database incorporates the computational advancement of calculating accessibility continuously for every minute within a departure time window of interest. This increases computational complexity, but provides a very robust representation of the interaction between transit service frequency and accessibility at multiple departure times.