United States

Making progress despite policy gridlock

The United States has created a “messy but useful” combination of incentives, regulation, persuasion, and innovation at the federal and state level, which has contributed to a recent decline in emissions. Sustaining and escalating this emissions decline while creating more cost-effective policy in the face of tightened government spending is the next challenge.


These graphs show the changes in emissions, emissions drivers, and policy in the Transportation sector in the US


Emissions Emissions and transport activity

Both passenger and freight travel increased significantly since 1980. Passenger travel dropped significantly during the recession.


    Emissions Drivers Emissions intensity

    Large gains in vehicle engine and transmission efficiency did not result in significant fuel efficiency gains, as cars became heavier. There was little shifting between transport modes (not shown).


      Policy Corporate average fuel economy standards

      Fuel efficiency standards remained largely unchanged for over two decades. Only recently have standards for passenger vehicles been revisited.

        • Deregulation and energy efficiency were the major policy themes for the 1980s as the air and rail industries underwent significant overhauls and passenger vehicle fleet efficiency standards increased significantly in the first half of the decade.

          • Policy Barriers

            • Corporate Average Fuel Economy Standards (CAFE) improved automobile efficiency
              Energy Policy and Conservation Act of 1975 required 27.5 mpg by 1985
              EPA began labeling fuel efficiency
            • Surface Transport Assistance Act, 1982 goal to complete Interstate Highway System by 1991
            • Raised federal gas tax from 4 to 9 cents per gallon—first increase since 1959—to fund completion of Interstate Highway System by 1991 (CRS 2006)
            • Surface Transport and Uniform Relocation Assistance Act, 1987
              Allowed states to raise speed limits to 65 on rural interstate highways
            • Railroad and Airline deregulation
              Railroad Deregulation and Regulatory Reform Act, 1976
              Staggers Act, 1980
              Airline Deregulation Act, 1978
          • Underlying changes

            • Oil shocks
            • Increasing fuel economy (approximately 20%) across ground transport
              Efficiency gains limited to first half of the decade (Joskow 2001)
            • Rapid changes to light duty fleet mix
              Light truck share increased from 16% to 30%
              Car share decreased from 83% to 70% (ORNL 2012)
        • The 1990s saw stable energy prices and an associated drop in attention towards increasing overall energy efficiency. Consumption behavior shifted towards larger, amenity-rich vehicles.

          • Policy Barriers

            • No change to CAFE standards
            • Gas taxes raised from 9 to 18 cents from 1990 to 1993, the last time federal gas taxes increased significantly
            • Energy Policy Act, 1992
              Federal fleet purchasing required to build alternative-fuel vehicle fleet
            • Clean Air Act Amendments, 1990
              Increased stringency of heavy and light duty pollution standards
            • Communications, Navigation, and Surveillance / Air Traffic Management (CNS/ATM), 1997, aimed to reduce airplane idling and travel time
          • Underlying changes

            • Deteriorating fuel economy in passenger vehicles (EIA 2005)
              Engine and transmission efficiency gains were offset by horsepower, size, and weight increases
              Continued changes to light duty fleet mix
              Light truck share rose to 40%
              Car share decreased to 60% (ORNL 2012)
        • Both the automobile market and policymakers shifted focus towards lighter, more efficient vehicles and alternative fuels. The financial crisis and automobile industry bailout late in the decade reshaped the policy landscape in favor of more stringent regulation.

          • Policy Barriers

            • Continued tightening pollution standard for heavy and light duty vehicles
            • High Occupancy Vehicle lane exemptions for lowemissions or hybrid vehicles, 2005
            • Energy Policy Act, 2005
              Tax incentives created for alternative fuel and advance technology vehicles
              Renewable Fuel Standard (RFS) established to mandate biofuel volumes in national fuel supply
            • Energy Independence and Security Act, 2007
              Advanced Technology Vehicles Manufacturing Loan Program
              Increased RFS volumes and set greenhouse gas requirements for qualifying fuels
            • SmartWay voluntary program established to facilitate fuel efficiency and reduced costs for freight, 2004
          • Underlying changes

            • Fleet mix changes slowed (ORNL 2012)
            • Increased use of hybrid and other alternative-fuel vehicles
            • Return to high oil prices
            • 2008-2009 recession reduced travel and freight movement (ORNL 2012, FHA 2012)
            • Domestic commercial aircraft improved in operational efficiency and fuel efficiency; passenger demand grew (CRS 2010)