Using Spatial Indicators for Pre-and Post -Development Analysis of TOD Areas: A Case Study of Portland and the Silicon Valley

Using Spatial Indicators for Pre-and Post -Development Analysis of TOD Areas: A Case Study of Portland and the Silicon Valley

Abstract: 

Understanding how smart growth theories are translated into practice is an important endeavor for planners, researchers, and the general public to both evaluate past efforts and to plan for new ones. This study uses a series of spatial indicators to visualize and quantify eight transit-oriented development (TOD) areas in Portland and Silicon Valley. More specifically, this report uses a spatial-temporal analysis to measure transit usage, urban form, and socio-demographic change prior and subsequent to the incorporation of light rail and transit-oriented development policies in these two regions.

A particular focus of this research is on the consistency of the urban mobility infrastructure with pedestrian access to the transit stops because the capacity for transit users to walk to and from their transit point of entry is a critical component of the overall TOD concept. Three key techniques to visualize and quantify walkability are presented: street network classification, pedestrian catchment areas, and intersection intensities. While such measures have been used elsewhere, this paper introduces the idea of impedance, which is incorporated into each of these measures presenting a refined method of analysis that distinguishes between an auto-oriented and pedestrian-oriented street network.

The general results of this research show that: the change to non-automotive use for work trips is mixed and that Portland is developing much more consistently with smart growth principles than Silicon Valley. More specifically, the impedance based walkability analysis challenges some theoretical extents of TOD theory, including: road types impact walkable service areas; actual areas of potential walkability are dramatically smaller than theoretical areas, with irregular coverage patterns; major roads present spatial barriers between areas of high connectivity and stations; and areas of high connectivity are often spatially separate from transit stops.

Finally, this report makes extensive use of geographic information system (GIS) technology to both visually and quantitatively capture a series of phenomena related to TOD areas. Focus has been placed on representing the visual images in ways that can enhance a broad understanding of the issues and in an effort to enhance potential participation of a broader public into the smart growth policy making process–an area of policy increasingly pursued in communities throughout the United States.

Authors: 

DR. MARC SCHLOSSBERG

Dr. Marc Schlossberg is an assistant professor of Planning, Public Policy, and Management (PPPM) at the University of Oregon. He holds a B.B.A. in Marketing from the University of Texas-Austin, an M.U.P. in Urban and Regional Planning from San José State University, and a Ph.D. in Urban, Technological, and Environmental Planning, with a certificate in Transportation Logistics planning from the University of Michigan. Dr. Schlossberg is also part of the STELLA (Sustainable Transport in Europe and Links and Liaisons with America) thematic network as a NextGen scholar, participating in a cross-Atlantic group of transportation scholars in a variety of areas that intersect transportation and sustainability. Dr. Schlossberg works more generally in the area of social planning, focusing on a variety of topics in his research and teaching, including: GIS and the nonprofit sector, GIS and public participation, visualizing accessibility, social change, bicycle planning and the transportation disadvantaged.

EARL G. BOSSARD, PH.D., AICP

Dr. Bossard is a professor of Urban and Regional Planning at San José State University. He holds a B.S. and a M.S. in economics from the University of Wisconsin-Milwaukee, and a Ph.D. in City and Regional Planning from Harvard. He has worked extensively on computer applications for urban analysis and planning, with special emphasis on geographic information systems, spreadsheets, and census data. He recently produced the final report and oversaw the production of a Mineta Transportation Institutefunded research project entitled Envisioning Neighborhood with Transit-Oriented Development Potential (MTI Report 01-15). That work has been futher transformed into book form and is in press with ESRI Press.

Published: 

September 2004

Keywords: 

Community planning
Transit riders
Transportation planning
Urban planning
Walking distance