Generating Route-Level Mutually Exclusive Service Areas

Abstract

Willing-to-walk distance was investigated as a means of measuring spatial accessibility of bus stops and of examining the effectiveness of alternative methods of generating mutually exclusive transit service areas at the route level. First, the walking distance to and from a transit stop was investigated with onboard survey data. Two methods in geographical information systems—the combination of Thiessen polygon and buffer and the network distance-based service area—were compared as strategies for generating mutually exclusive service areas. For the examination of the effectiveness of these two methods, all mutually exclusive service areas were validated with a spider diagram generated from an onboard survey. Measures of urban form were also statistically tested for comparison of the two methods. A case study of a single route, serving the Minneapolis–Saint Paul, Minnesota, metropolitan area, was performed with data from various sources, such as Google's General Transit Feed Specification, an onboard survey, parcel-level land uses, and the U.S. Census street network. Validation with onboard survey data demonstrates the strengths of each method. Results also show that the network-based service area, a popular geographical information system method for service area analysis, does not yield a more meaningful strategy for generating mutually exclusive transit catchment areas, especially when spacing between stops is very small.