Opportunity-Based Dynamic Transit Accessibility in Southern California

Accessibility to public transportation is an important element for the specification of activity participation and travel behavior models, the assessment of level of service by public transportation, equity analysis, and the design of public transportation provision. Although transit ridership is lower in the United States than in other countries, transit serves a segment of the population that may benefit substantially from its provision. The relative attractiveness of public transportation depends critically on its performance in terms of the accessibility provided to link people with employment and activity opportunities. In practice, an effective method to derive such indicators and related performance measures is lacking. An opportunity-based transit accessibility measure applied to the Southern California Association of Governments megaregion is presented. The indicators computed are sensitive to the availability of opportunities for travelers within a day (e.g., related to the opening and closing hours of businesses) and are a direct function of the transit routes and schedules and the associated spatiotemporal variation of level of service during a day. The method is described, examples on transit accessibility are provided, and the results are compared with automobile accessibility.