Impacts of Transportation Policies on Greenhouse Gas Emissions in U.S. Regions

December 7, 2011

A new report by David T. Hartgen, a senior fellow at the Reason Foundation, M. Gregory Fields, a graduate student at the University of North Carolina at Charlotte, and Adrian Moore, vice president of policy at the Reason Foundation, compares the cost and effectiveness of improved fuel economy, transportation system improvements and shifts in travel behavior on the reduction of man-made carbon dioxide (CO2) emissions in urban areas.

  • The report quantifies how much CO2 cars, light trucks and commercial trucks currently emit (base year 2005) in each region, how much CO2 would have increased with prior CAFE standards, how much the new CAFE standards will reduce, and how much CO2 might be reduced by other commonly suggested policies.
  • These policies include the new fuel economy standards, additional smaller-car sales, signal timing and speed controls, capacity increases, high-occupancy or priced lanes, travel reduction polices, transit use increases, carpooling, telecommuting and walking to work.

The authors find that policies aimed at reducing transportation-related CO2 emissions by improving overall fleet fuel efficiency are likely to have the greatest relative and most cost-effective impact. 

  • Overall, technological improvements to vehicles resulting in higher fuel efficiency, along with traffic signal timing and speed harmonization, hold out the most hope for significant reductions in future CO2 emissions.
  • Likely to be less effective are major capacity increases, more high-occupancy vehicle or standalone high-occupancy toll lanes, transit shift policies and carpooling.
  • However, none of the reviewed policies alone, including the new CAFE standards, is likely to reduce global CO2 emissions by more than about 2 percent, and most policies would have less than a 0.2 percent impact on global CO2 emissions.

This means that even if implemented across many U.S. regions in a concerted fashion, the policies reviewed here would not likely have a significant effect on global CO2 emissions.  And at the regional level they may prove very difficult to implement and may not even reduce CO2 emissions significantly.

Source: David T. Hartgen, M. Gregory Fields and Adrian Moore, "Impacts of Transportation Policies on Greenhouse Gas Emissions in U.S. Regions," Reason Foundation, November 30, 2011.

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