Who Can Access Transit? Reviewing Methods for Determining Population Access to Bus Transit

Steven Biba
University of Texas at Dallas

Kevin M. Curtin
Germana Manca
George Mason University

SpAM
SpAM (Spatial Analysis and Methods) presents short articles on the use of spatial statistical techniques for housing or urban development research. Through this department of Cityscape, the Office of Policy Development and Research introduces readers to the use of emerging spatial data analysis methods or techniques for measuring geographic relationships in research data. Researchers increasingly use these new techniques to enhance their understanding of urban patterns but often do not have access to short demonstration articles for applied guidance. If you have an idea for an article of no more than 3,000 words presenting an applied spatial data analysis method or technique, please send a one-paragraph abstract to rwilson@umbc.edu for review.

This article explores the use of Geographic Information Systems in determining transit service areas. The traditional methods of determining the population that can access transit are briefly reviewed, and a new method is proposed. The parcel-network method takes advantage of the spatial and aspatial attributes of parcels, and the ability to easily determine network distances from parcels to bus stop locations. This parcel-network method avoids the well-known and unrealistic assumptions associated with the existing methods, and reduces overestimation of the population with access to transit, resulting in improved spatial precision and superior inputs to transit-service decisionmaking processes. The way in which this new method is performed is examined in detail. The study area consists of a section of the bus network within the Dallas metropolitan area. This article summarizes the work of the authors in a research article entitled, "A New Method for Determining the Population With Walking Access to Transit" and published in the International Journal of Geographical Information Science (Biba, Curtin, and Manca, 2010).