Access Across America: Transit 2017
Andrew Owen, Brendan Murphy
Report no. CTS 18-12
Accessibility is the ease and feasibility of reaching valued destinations. It can be measured for a wide array of transportation modes, to different types of destinations, and at different times of day. There are a variety of ways to measure 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.
This study estimates the accessibility to jobs by transit and walking for each of the United States' 11 million census blocks, and analyzes these data in 49 of the 50 largest (by population) metropolitan areas. Transit is used for an estimated 5 percent of commuting trips in the United States, making it the second most widely used commute mode after driving. Travel times by transit are calculated using detailed pedestrian networks and full transit schedules for the 7:00 - 9:00 a.m. period. The calculations include all components of a transit journey, including "last-mile" access and egress walking segments and transfers, and account for minute-by-minute variations in service frequency.
This report presents detailed accessibility values for each metropolitan area, as well as block-level maps that illustrate the spatial patterns of accessibility within each area. A separate publication, Access Across America: Transit 2017 Methodology, describes the data and methodology used in this evaluation.
This analysis uses the same tools and techniques as Access Across America: Transit 2015 and 2016, and at the same fully national scale; availability of GTFS data has increased in consistency. For these reasons, direct comparisons between transit accessibility results of 2015 and 2016 are possible, and comparisons and time-series analysis are included in these reports going forward.