The new fuel economy standards are the latest assault on Biden-era EV policies. President Donald Trump announced Saturday that he has approved new fuel economy standards for passenger vehicles, in another move meant to take aim at Biden-era policies supporting electric vehicles.

Trump said in a Truth Social post that he “just approved new Fuel Economy Standards that TERMINATE Sleepy Joe Biden and Pete Boot-EDGE-EDGE’s ridiculous EV Mandate. The Dumocrats cost our Great Auto Manufacturers $Billions, forced Americans into cars they never wanted, and wasted Billions on Chargers that were never built.” The announcement comes as the White House faces increased scrutiny for high gas prices — hovering just under $4.50 a gallon on average in the U.S. Saturday — rising car prices and a tough midterm election on the horizon.

“These new Standards will take the waste out of building cars in America. That means LOWER PRICES, saving families thousands on a new, beautiful, and safe car — Far better than the Environmental Monsters that we were building heretofore. Every Manufacturer, from General Motors to Ford to Stellantis, has called me wanting to build here, and now they can!” Trump wrote.

The final rule was not immediately available, and officials from the White House did not immediately respond to questions. Transportation Secretary Sean Duffy amplified Trump’s post on social media, adding, “A major victory for America’s auto workers is COMING MONDAY.” The new regulation is expected to slash fuel economy standards for passenger vehicles by nearly one-third through model year 2031.

The National Highway Traffic Safety Administration’s proposed redo of so-called Corporate Average Fuel Economy standards for cars and light-duty trucks would require the sector to average about 34.5 miles per gallon through model year 2031. The rule replaces Biden-era standards, which demanded fleetwide averages of 50.4 mpg. The revision is one more nail in the coffin for Biden administration electric vehicle incentives.

But experts say its comparatively less important than EPA’s move in February to scuttle all climate rules for motor vehicles — including the scientific finding that underpinned them. That’s in part because Congress approved language in last year’s tax and spending megabill that set aside penalties that carmakers previously paid for failing to meet the fleetwide fuel economy averages.

Joshua Linn, a professor at the University of Maryland, said the One Big Beautiful Bill Act’s repeal of noncompliance penalties transformed the CAFE standards into a “suggestion.”

“It’s like the agency’s asking nicely, ‘here’s where you could be if you added this much technology and made your gasoline cars this much more efficient,’” said Linn, who is also a senior fellow at Resources for the Future. “But there’s no penalty if you don’t do it.” Whether manufacturers choose to meet those standards or not will now be based on business considerations, not government requirements.

NHTSA’s revised standards will almost certainly be challenged in court, as EPA’s repeal of vehicle emissions rules and the so-called endangerment finding for greenhouse gases has been.

The courts will decide whether the government can or must require carmakers to improve their fuel economy or invest in electrification. But the rollbacks and Congress’ move last year to gut consumer tax incentives for electric vehicles has widened the gap between U.S. transportation policy and global trends favoring EVs.

Dan Becker, director of the Safe Climate Transport Campaign at the Center for Biological Diversity, said the Trump repeals wouldn’t do the U.S. car industry any favors.

“This is at a time when the rest of the world is moving to Chinese advanced technology electric vehicles,” he said. “So, this essentially says, ‘okay, Detroit, you can fail to compete into oblivion.’”