Comparative Study of Pedestrian Accessibility to Transit Stations Using Free and Proprietary Network Data

Availability of a transit service is a key factor in a traveler's choice of transportation mode. Transit service is a realistic option only if the service is available at or near locations when a person plans to travel. Whereas various measures exist for transit availability such as service frequency, the focus of this study was on the spatial aspect of pedestrian accessibility to transit stations, that is, on service coverage. Service areas are commonly used to visualize accessibility for pedestrians to transit systems and to analyze the potential ridership. Because the service area for a station is defined over the maximum network walking distance from a transit station, a complete street network that includes pedestrian segments, that is, shortcuts, is highly important for a realistic assessment of service areas. Whereas most proprietary geodata providers concentrate solely on car-related geodata, public domain street data and volunteered geographic information, such as OpenStreetMap, provide a potential valuable source for pedestrian data. The authors compared the amount of pedestrian-related data between freely available sources (OpenStreetMap or TIGER or both) and proprietary providers (Tele Atlas or NAVTEQ or both). The effect on modeling transit accessibility for pedestrians was analyzed for five U.S. and four German cities, and differences between these two countries were identified.