VMT Reduction Is the Wrong Goal for Transportation Policy

One of the leading academic transportation policy journals, Transportation Research Part A: Policy and Practice, invited Adrian Moore, Sam Staley, and Bob Poole to write an essay for a symposium on vehicle-miles-traveled (VMT) reduction as a policy goal in battling climate change. Our essay, titled “The Role of VMT Reduction in Meeting Climate Change Policy Goals” is now available on-line; here is the abstract:


This article evaluates the case for vehicle miles traveled (VMT) reduction as a core policy goal for reducing greenhouse gases (GHGs), concluding the economic impacts and social consequences would be too severe given the modest potential environmental benefits. Attempts to reduce VMT typically rely on very blunt policy instruments, such as increasing urban densities, and run the risk of reducing mobility, reducing access to jobs, and narrowing the range of housing choice. VMT reduction, in fact, is an inherently blunt policy instrument because it relies almost exclusively on changing human behavior and settlement patterns to increase transit use and reduce automobile travel rather than directly target GHGs. It also uses long-term strategies with highly uncertain effects on GHGs based on current research. Not surprisingly, VMT reduction strategies often rank among the most costly and least efficient options. In contrast, less intrusive policy approaches such as improved fuel efficiency and traffic signal optimization are more likely to directly reduce GHGs than behavioral approaches such as increasing urban densities to promote higher public transit usage. As a general principle, policymakers should begin addressing policy concerns using the least intrusive and costly approaches first. Climate change policy should focus on directly targeting greenhouse gas emissions (e.g., through a carbon tax) rather than using the blunt instrument of VMT reduction to preserve the economic and social benefits of mobility in modern, service-based economies. Targeted responses are also more cost effective, implying that the social welfare costs of climate change policy will be smaller than using broad-brushed approaches that directly attempt to influence living patterns and travel behavior.

Samuel R. Staley, Ph.D. is a senior research fellow at Reason Foundation and managing director of the DeVoe L. Moore Center at Florida State University in Tallahassee where he teaches graduate and undergraduate courses in urban planning, regulation, and urban economics. Prior to joining Florida State, Staley was director of urban growth and land-use policy for Reason Foundation where he helped establish its urban policy program in 1997.