Grantee Research Project Results
2008 Progress Report: Metropolitan Accessibility and Transportation Sustainability: Comparative Indicators for Policy Reform
EPA Grant Number: R833349Title: Metropolitan Accessibility and Transportation Sustainability: Comparative Indicators for Policy Reform
Investigators: Levine, Jonathan , Simon, Carl , Grengs, Joe , Shen, Qing , Zielinski, Susan
Current Investigators: Levine, Jonathan , Grengs, Joe , Shen, Qing , Shen, Qingyun
Institution: University of Michigan , University of Maryland - College Park
EPA Project Officer: Hahn, Intaek
Project Period: February 1, 2007 through January 31, 2010 (Extended to January 31, 2011)
Project Period Covered by this Report: February 1, 2008 through January 31,2009
Project Amount: $300,000
RFA: Collaborative Science And Technology Network For Sustainability (2006) RFA Text | Recipients Lists
Research Category: Pollution Prevention/Sustainable Development , Sustainable and Healthy Communities
Objective:
We are working toward the development of indicators of transportation accessibility that can be compared between 30 of the largest metropolitan regions in the United States. Underpinning this research are two core ideas. First is the notion that the purpose of transportation is not movement, but access. Traditional transportation-evaluation measures focus on mobility, which one means to provide access. A more supportable approach to transportation evaluation would incorporate both mobility and proximity in metrics of accessibility. The second idea is that by redefining transportation needs in a potentially less environmentally consumptive fashion, accessibility offers a basis for sustainability-oriented transportation policy reform.
We are particularly interested in the urban-form factors that influence accessibility, including density, centralization, concentration and walkable and transit-oriented development.
Progress Summary:
Activities during Years 1 and 2 focused on data collection, resolution of methodological issues, development of standard routines for data analysis, development of urban-form metrics, and analysis of accessibility between 24 metropolitan regions. We: (1) collected data from the travel demand models of 35 metropolitan planning organizations needed for our accessibility analysis; (2) acquired other needed data, including a nationwide database of employment locations; (3) developed methodologies for standardizing accessibility comparison between metropolitan regions, measuring non-work accessibility, and characterizing metropolitan form; (4) calculated work and non-work accessibility metrics for 24 metropolitan regions; (5) analyzed accessibility data jointly with urban form metrics; and (6) submitted one journal article with initial findings, and will present fuller findings at a World Bank conference in climate change in Marseille, France in June 2009.
Results suggest that work accessibility by car is strongly influenced by overall metropolitan densities, and secondarily influenced by metropolitan centralization (which we define tentatively as the share of the population living in areas of job density at least three standard deviations above the average). Areas of high average metropolitan densities tend to show high accessibility scores, as do areas with high levels of metropolitan centralization. High average overall densities seem more significant than the presence of concentrated nodes of transit-oriented development, which may suffer from the “drop-in-the-bucket” phenomenon currently: they provide high accessibility to their residents but are too small relative to the metropolitan region as a whole to affect overall accessibility statistics appreciably.
Future Activities:
Major activities for the next year include continuing to complete accessibility calculations for more metropolitan areas, to formalize analyses of accessibility and urban form, and to resolve apparent data discrepancies with transit modeling data that we received from the metropolitan planning associations. In contrast to auto-network data, the transit data we received appears to be producing anomalous results. This may be a function of how different travel models treat transit headways.
Journal Articles:
No journal articles submitted with this report: View all 20 publications for this projectSupplemental Keywords:
Urban form, centralization, concentration,Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.