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Measuring Change in Small-Scale Transit Accessibility with Geographic Information Systems: Buffalo and Rochester, New York
Journal Transportation Research Record
Publisher Transportation Research Board of the National Academies
ISSN 0361-1981
Issue Volume 1887 / 2004
Category Public Transit
DOI 10.3141/1887-02
Pages 10-17
Online Date Tuesday, January 30, 2007
Abstract
A new method has been developed to measure directly changes in transit accessibility—the combined spatial effect of shifts in land use patterns and transit service—between metropolitan jobs and census tracts with high proportions of the people who most depend on good transit. Through focused analysis of transit routes serving one neighborhood in Buffalo and one neighborhood in Rochester, New York, two main questions are addressed. First, did transit-dependent poor people who lived in inner-city neighborhoods lose capacity to access jobs by transit during the 1990s? Second, if so, how much of the reduction in accessibility was due to changes in transit service rather than to dispersion of land use? Steps include formulating a gravity model using geographic information systems (GISs), calculating an accessibility index at two times during the 1990s at the census tract level, and disaggregating the accessibility change into subcomponents of change in land use and change in transit service by holding relevant variables constant to a base year. Findings do not support the a priori expectations: the transit component of change does not appear to contribute to a loss in accessibility from high-poverty neighborhoods. The model provides insights into the causes of accessibility change, the geographic distribution of accessibility change, and better assessments of whether transit agencies are successfully adapting to changes in land use.
Transportation policies, infrastructure, and operation have enormous impacts on New York's economy, and upon the quality of life of every New Yorker. Our transportation network plays a major role in determining where we can live and work, and is a key driver of land use and value. Transportation infrastructure itself can be a boon, or a burden. Transit nodes can leverage density and create vibrant neighborhood hubs; greenways provide not only mobility options, but green open space in areas where parkland is scarce. But highways, bus depots, and railyards can also fragment and blight neighborhoods, creating large local costs, and little local benefit.
The Pratt Center's Transportation Equity project will examine ways that New York's transportation systems can help to create a city that offers opportunity and a high quality of life to all of its residents. During the next two years, Pratt Center staff will work with community and civic organizations to analyze our transportation systems from an equity perspective, and to develop proposals and strategies for maximizing their benefits to all New Yorkers. The project is timely; transportation initiatives now being debated will shape our city and region for the next century. But the voices of communities with the most at stake are rarely heard in the discussion. Grassroots organizations may advocate for or against individual projects, but are less often involved in the technical and political processes that shape transportation infrastructure and policy priorities overall. The Transportation Equity project will develop tools to enable social and environmental justice advocates to participate effectively in decisions that will have far-reaching impacts on the communities that they represent.
The project is funded by a federal grant authorized under the August 2005 federal surface transportation reauthorization bill- the Safe, Accountable, Flexible, and Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU)- and administered by the New York State Department of Transportation.