The Environmental Protection Agency unveiled this week its final rules for reducing emissions from heavy-duty trucks, including semitractor-trailers, buses, and other heavy trucks.

The agency said the new rules would cut carbon dioxide emissions by 1.1 billion tons, cut fuel costs by $170 billion, and save roughly 2 billion barrels of oil over the lifetime of the vehicles sold under the new program. Medium- and heavy-duty trucks contribute 20 percent of the country's transportation emissions, but comprise about 10 percent of cars on the road.

“The actions we take today on climate change will help lessen the impacts on future generations,” EPA Administrator Gina McCarthy said in a statement. “This next phase of standards for heavy- and medium-duty vehicles will significantly reduce greenhouse gas emissions while driving innovation, and will ensure that the United States continues to lead the world in developing fuel-efficient technologies through the next decade and beyond.”

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The new rules are the second phase of an initiative by the EPA to reduce greenhouse gases in the U.S. The proposed standards were introduced last year, but the finalized program announced this week is much more stringent than the initial proposal.

The standards outline an ambitious plan to cut emissions in long-haul trucks and vocational vehicles by roughly 25 percent by 2027, and heavy-duty pickups by 16 percent.

The EPA says owners would recoup the expense for more fuel-saving technology in those semi-trucks in only two years, which could cost as much as $12,000 per vehicle.

Industry insiders praised the new rules and said it largely be a boon for the environment and industry.

“Meeting the challenges set forth in the first phase of these rules has been underway since 2014, and won’t be fully implemented until 2017. In the days ahead we will be fully reviewing and offering additional insights on this new complex rule, and are hopeful that the new goals established here achieve an effective balance of meeting customer demands and societal goals,” Allen Schaeffer, executive director of the pro-diesel group, Diesel Technology Forum, said in a statement.

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Heavy-duty pickups, which contribute about 23 percent of all heavy-duty emissions, would face more stringent requirements to meet fuel economy under the program.

Beginning in 2021 the rules would ratchet down emissions by 2.5 percent each year until 2027. Heavy-duty trucks and vans would be evaluated on a "work factor" standard that would combine payload, towing capacity, and four-wheel-drive into a formula to determine their target fuel economy.

The agency estimates the additional cost for fuel-saving technology could be as much as $1,300 per truck and listed numerous ongoing programs such as hybridization and weight reduction that could help those trucks meet new standards.

The agency admitted in its report that many heavy-duty trucks are being used similarly to light-duty vehicles—passenger cars and trucks—and should be subject to the same rules.