Connecting to Opportunity: Access to Jobs via Transit in the Washington, D.C. Region, Martha Ross and Nicole Prchal Svajlenka, November 8, 2012. “Findings – An analysis of the public transit systems serving the Washington, D.C. region finds that:

• Nearly 90 percent of residents in the Washington region live in neighborhoods with access to transit coverage of some kind, whether bus, Metrorail, or commuter rail. Coverage rates vary greatly across the region, however, from at or near 100 percent in the District, Arlington, Alexandria and the close-in parts of Montgomery, Prince George’s, and Fairfax counties, to smaller shares in Loudoun (72 percent), Prince William (67 percent), and Frederick (41 percent) counties.
• Due to broad transit coverage and proximity to job centers, job access via transit is strongest in the District, Arlington, and Alexandria, with access rates dropping based on distance from the core. However, close-in areas of Montgomery, Prince George’s and Fairfax counties can also reach substantial numbers of jobs via transit. Across all jurisdictions, access to employment via transit is higher at the 90-minute commute threshhold than at 60 or 45 minutes, although residents in or near the regional core can still access substantial numbers of jobs at these lower time thresholds.”