In November, the Environmental Protection Agency (EPA) and the Department of Transportation (DOT) rolled out the second stage of a joint rulemaking effort to set higher miles-per-gallon (mpg) fuel economy and greenhouse gas (GHG) pollution standards for passenger cars and light trucks. This latest regulatory proposal builds on the first phase (2012-2016) of the Obama administration’s MPG/GHG program, which it said will raise fuel efficiency equivalent to 35.5 mpg by 2016 and result in an average light-vehicle tailpipe carbon dioxide (CO2) level of 250 grams per mile.

Combined with 2011 fuel economy standards and the standards in effect for 2012-2016, the latest proposal represents the most significant federal action ever taken to reduce greenhouse gas emissions and improve fuel economy, the agencies said. Taken together, the agencies said those actions would reduce greenhouse gas emissions by half and result in model year 2025 light-duty vehicles with nearly double the fuel economy of model year 2010 light-duty vehicles.

The two agencies also are imposing the first of its kind fuel efficiency standards for commercial vehicles to go into effect in stages between 2014 and 2018. The rules, however, impose different fuel efficiency targets based on the size and weight of the vehicle involved:

  • Vocational vehicles — including delivery trucks, buses, and garbage trucks — will be required to reduce fuel consumption and greenhouse gas emissions by approximately 10 percent by model year 2018. The trucks could save an average of 1 gallon of fuel for every 100 miles.
  • For heavy-duty pickup trucks and vans, separate standards are required for gasoline-powered and diesel trucks. The vehicles will be required to achieve up to about a 15 percent reduction in fuel consumption and GHG emissions by model year 2018. Under the final standards, a typical gasoline or diesel-powered heavy-duty pickup truck or van could save 1 gallon of fuel for every 100 miles.

DOT and EPA noted that different measurements will apply to each vehicle category. For example, heavy-duty pickup trucks and vans must meet targets for gallons of fuel consumed per mile as well as grams of carbon dioxide (CO2) emissions per mile. However, vocational vehicles must meet targets for gallons of fuel consumed and GHG emissions per ton-mile.