Accessibility research may shed light on managing traffic patterns and congestion, urban growth, and wise land use.
Accessibility: Rethinking the way we look at transportation
Rethinking the way we look at transportation
By Pamela J. Snopl
Published on November 19, 2004
By all accounts, traffic congestion is a growing concern around the country. In 2002 alone, congestion is estimated to have cost motorists roughly $63 billion in 85 metropolitan areas, or $829 per person. And in the Twin Cities metro area, congestion has grown at one of the fastest clips in the nation. But is congestion truly the best measure of how well the transportation system is meeting our needs?
A new approach, which looks at the access people have to their various destinations, is now gaining ground. Accessibility research concentrates on how--and how well--people get to the places they want or need to go to. For example, a resident outside Fargo may be able to zip to work with no congestion at all but still be 50 minutes from the closest job. Contrast that to the denser Twin Cities, where thousands of jobs and services are within a 15-minute trip even on congested roadways. The results of accessibility research can tell us much about managing traffic patterns and congestion, urban growth, and wise land use.
Researchers from the University of Minnesota and other organizations presented their findings in this new field on November 8-9 at "Access to Destinations: Rethinking the Transportation Future of Our Region," part of President Bob Bruininks's 21st Century Interdisciplinary Conference Series.
... while people are driving more miles, said Bertini, their total daily travel time "budget" has remained constant--at about one hour--over the past 20 years, and some argue, over hundreds of years.The University's Center for Transportation Studies (CTS) in cooperation with the Center for Urban and Regional Affairs, the College of Continuing Education, the Humphrey Institute of Public Affairs, and the Institute of Technology sponsored the conference, which attracted more than 150 researchers and practitioners. The event also marked the kickoff of a new University of Minnesota collaborative research program studying accessibility in the Twin Cities area.
Exploring accessibility demands a more detailed understanding of traffic and new techniques to measure it, said Robert Bertini, associate professor at Portland State University. Even for congestion, there is no agreement on an absolute definition or on the best way to gauge it. What does seem clear, said Bertini, is that while people are driving more miles, their total daily travel time "budget" has remained constant--at about one hour--over the past 20 years, and some argue, over hundreds of years.
What's changing is how Americans live and work. With decentralized cities, dual-earner households, and dispersed businesses, "the old model of the transportation and land-use connection is quite oversimplified and may even be obsolete," said Rachel Weinberger of the University of Pennsylvania.
Further weakening the link between where we live and how we get to work is the rapid development of information and communications technologies. "There is no clear connection anymore between work and a physical place for more and more people," said Harvey J. Miller, a geography professor at the University of Utah.
Another question researchers must understand is this: Can the way we use our land change transportation behavior, relieving congestion, for example? For Gerrit Knaap, professor of urban studies and planning at the University of Maryland, tools such as zoning and growth boundaries can work, but they're better at limiting growth than stimulating transit-oriented development. And because local policies can be counterproductive, success will require regional institutions with the capacity to design integrated land-use and transportation plans, plus the regulatory power to make them stick. Otherwise, he said, just as "we can't build our way out of congestion, we can't 'land use' our way out of it either."
While higher density, mixed-used development does reduce the length of a typical trip, drivers may take shorter trips more often, so vehicle miles traveled (VMT) could rise--or fall, said Randall Crane, professor of urban planning at UCLA. Likewise, there are no definitive answers to tell us if such "smart growth" patterns would reduce commutes.
What does seem effective in reducing congestion are travel-demand management strategies such as toll lanes, ridesharing, and congestion pricing. These "non-coercive" incentives give people a choice to avoid congestion, said Jonathan Gifford of the George Mason University School of Public Policy. People, however, continue to live in congested areas, like Los Angeles and New York, so they must believe the benefits of these strategies outweigh the costs.
Congestion as a sign of successful, affluent areas has implications for next steps, said Lance Neumann, president of Cambridge Systematics. "You can have a lot of investment in transportation and a lot of land use regulation and observe, five years later, similar or worse congestion, and yet be in a much stronger economic competitive position," he said. Hong Kong is very congested and very economically successful, for example.
Accessibility research could also warn us when the public's assessment of the transportation system veers from the engineering assessment, said Alan Pisarski, an independent consultant. With a real potential for disconnect, we need to find out what level of congestion triggers voters to start "unelecting" public officials [as a way to voice their displeasure].
A summary of the "Access to Destinations: Rethinking the Transportation Future of Our Region" conference will be available from the Center for Transportation Studies in 2005; call 612-626-1077 or visit www.cts.umn.edu.