Accessibility, a measure that examines both land use and transportation systems, is the ease of reaching valued destinations. It can be measured for various transportation modes, to different types of destinations, and at different times of day. There are a variety of ways to define accessibility, but the number of destinations reachable within a given travel time is the most comprehensible and transparent, as well as the most directly comparable across cities.
The Access Across America series, begun in 2013, measures accessibility to jobs via various modes of transportation in major metropolitan areas across the United States. Projects in the series are conducted by the University of Minnesota's Accessibility Observatory with funding from CTS and the National Accessibility Evaluation pooled-fund study.