The U.S. Environmental Protection Agency and the U.S. Dept. of Transportation have put forth the first national standards to cut greenhouse-gas emissions and raise the fuel efficiency of heavy-duty trucks and buses.

The proposal, which the agencies announced on Oct. 25, would apply to work vehicles ranging from large, heavy-duty pickup trucks in Class 2b to the largest Class 8 tractor-trailer trucks, weighing 80,000 lb or more. The EPA and DOT action follows a directive issued by President Obama.

The benchmarks would kick in for vehicles manufactured in model years 2014 through 2018. EPA and DOT estimate the standards will cut greenhouse-gas emissions by nearly 250 million metric tons and save 500 million barrels of oil over the lives of the vehicles produced during those years.

The proposal aims to reduce tractor-trailer trucks’ CO2 emissions and fuel consumption by 20% by the 2018 model year.

The target for heavy-duty pickup trucks and vans is a 10% cut in gasoline-engine fuel consumption and tailpipe emissions by the 2018 model year. It also would pare diesel-engine consumption and emissions by 15% for such pickups and vans.

EPA and DOT say this national program will enable manufacturers to meet one uniform standard rather than as many as 50 different state requirements. They also say owners should be able to recoup the vehicles’ higher cost through expected fuel-efficiency gains of 7% to 20%.

The agencies are providing 60 days for comments on the proposal.