The Trump administration is proposing new fuel economy standards for vehicles that would roll back efficiency rules implemented under former President Biden.

Under the Transportation Department proposal, which was unveiled at a White House event on Wednesday, automakers would need to meet less stringent vehicle mileage requirements. 

Federal fuel economy rules are overseen by the National Highway Traffic Safety Administration (NHTSA) under what's known as the CAFE (Corporate Average Fuel Economy) Standards. Enacted by Congress in 1975, the regulations stipulate how many miles vehicles must be able to drive on a gallon of fuel, with specific standards for light-duty vehicles, as well as medium- and heavy-duty trucks. 

The rules aim to reduce greenhouse gas emissions and help consumers save money on gas, according to the Transportation Department. Critics of the fuel standards have long argued they are costly for automakers, which must make technological improvements to reduce fuel usage, raising vehicle prices. 

The revamped fuel standards would reverse a Biden policy that "forced automakers to build cars using expensive technologies that drove up costs, drove up prices and made the car much worse," Mr. Trump said on Wednesday.

Rules would sharply lower mileage standard

If finalized, the plan would relax fuel economy standards by setting the industry average for light-duty vehicles at roughly 34.5 miles per gallon through the 2031 model year, lower than the 50 miles per gallon outlined by a Biden-era rule.

On Wednesday, Transportation Secretary Sean Duffy said the previous rules drove up the cost of new cars and were "completely unattainable" for automakers. He initially directed NHTSA to review the CAFE regulations in January.

The Transportation Department said the proposal is projected to save American families $1,000 on the average cost of a new vehicle and a total of $109 billion over the next five years.

NHTSA Administrator Jonathan Morrison said the move to ease the mileage standards would make the nation's roads safer. "Newer cars are safer cars and by reducing vehicle prices, more American families will be able to afford newer vehicles," he said in a statement. 

Mr. Trump was joined at Wednesday's event by senior auto industry executives. In a statement shared with CBS News, Stellantis CEO Antonioa Filosa expressed support for the proposed fuel efficiency rules, saying the initiative would realign the CAFE standards "with real-world market conditions as part of its wider vision for a growing U.S. automotive industry."

General Motors also backed the proposed fuel economy standards, which would need to undergo an official rulemaking process before being adopted. 

"GM supports the goals of NHTSA's proposed CAFE rule and its intention to better align fuel economy standards with market realities. We have long advocated for one national standard that upholds customer choice and provides the auto industry long-term stability," a spokesperson for the automaker said in a statement.

The fuel economy proposal would roll back a rule finalized in June 2024 under the Biden administration aimed at raising the minimum gas mileage for passenger cars and light trucks by model year 2031.

At the time, NHTSA said the new regulations would save Americans $23 billion at the gas pump and reduce pollution. Burning gas for vehicles is a major contributor to carbon emissions, which scientists have linked to climate change. 

The rules were also intended to spur automakers to produce more electric vehicles, a key Biden administration priority for the nation's transportation sector. 

Would new MPG rules ease car prices?

CarEdge CEO Zach Shefska described the Trump administration proposal as a win for automakers, but said consumers shouldn't expect to see lower car prices right away. That's because automakers work at least five years ahead in their product development, he said, meaning it would take a while before any redesigned cars make it onto the road.

If the proposal eventually does help lower vehicle prices, he said, "It will happen years from now, not in the coming weeks or months."

The Center for Biological Diversity, a nonprofit organization that works to protect endangered species, said the Transportation Department proposal will increase the country's oil consumption and undermine the competitiveness of U.S. automakers. 

"Trump's action will feed America's destructive use of oil, while hamstringing us in the green tech race against Chinese and other foreign carmakers," said Dan Becker, director of the Center for Biological Diversity's Safe Climate Transport Campaign.

Wednesday's move is the latest effort by the Trump administration to reverse Biden-era policies that encouraged automakers to build cleaner-running cars and trucks, including electric vehicles. The administration scrapped EV tax credits in September and has also proposed rules to eliminate gas emission regulations.