The U.S. Environmental Protection Agency (EPA) and the U.S. Department of Transportation (DOT) have proposed the first-ever fuel efficiency and greenhouse gas emission standards for heavy-duty trucks and buses.

According to the proposed regulations, vocational vehicles such as garbage trucks would have to implement engine and vehicle standards that would result in 10 percent reductions in both greenhouse gas emissions and fuel consumption from model year 2014 to model year 2018. New standards for tractor-trailers would achieve 20 percent reductions in both greenhouse emissions and fuel consumption during the same timeframe, according to EPA and DOT. For heavy-duty pick-up trucks and vans, the agencies are proposing 10 percent reductions in both greenhouse gas emissions and fuel consumption for gasoline vehicles, and 15 percent reductions for diesel vehicles.

"These new standards are another step in our work to develop a new generation of clean, fuel-efficient American vehicles that will improve our environment and strengthen our economy," said EPA Administrator Lisa P. Jackson in a statement that accompanied the release of the proposal. "In addition to cutting greenhouse gas pollution, greater fuel economy will shrink fuel costs for small businesses that depend on pick-ups and heavy-duty vehicles, [for] shipping companies[,] and [for] cities and towns with fleets of these vehicles. Those savings can be invested in new jobs at home, rather than heading overseas and increasing our dependence on foreign oil."

EPA and DOT say the new standards would reduce greenhouse gas emissions by approximately 250 million metric tons and cut oil consumption by 500 million barrels over the lives of the vehicles produced during the first five years of the program. The standards also would provide $41 billion in net benefits over the lifetimes of model year 2014 to 2018 vehicles, the agencies estimate.

Warrenville, Ill.-based Navistar was apparently one of the few truck manufacturers to comment in the immediate aftermath of the proposal's release. "While it's too soon to evaluate all elements of the proposed regulations, we are committed to engaging with the EPA and DOT on this issue," said Daniel C. Ustian, chairman, president and CEO of Navistar, in a statement. "We look forward to working together with government and industry leaders in the months ahead to implement changes that will benefit the customers and communities we serve with cleaner, more fuel-efficient commercial vehicles."

One prominent environmental organization, The Sierra Club, says the agencies should be more aggressive. "The Sierra Club is pleased that the DOT and EPA have made a first step in setting these critical and necessary standards for heavy-duty trucks, but we urge the [Obama] Administration to aim even higher, and we believe that a 35 percent decrease in greenhouse gas emissions from long-haul tractors pulling van trailers by 2018 is possible by setting standards for trailers and additional steps."

The federal government will accept public comments on the proposed standards for 60 days following their late October publishing in the Federal Register. For more information on the proposal and how to submit comments, visit the EPA's website or the National Highway Traffic Safety Administration's website.

"Through new fuel-efficiency standards for trucks and buses, we will not only reduce transportation's environmental impact, we'll reduce the cost of transporting freight," said U.S. Transportation Secretary Ray LaHood in a statement. "This is a win-win for the environment, businesses and the American consumer."