The Trump administration on Monday finalized a sweeping rollback of federal fuel economy standards, tearing up Biden-era mileage targets in an 892-page rule the Transportation Department dubbed "Freedom Means Affordable Cars." Transportation Secretary Sean Duffy said the new rule delivers "commonsense" requirements that will make vehicles more affordable, while NPR reports the change guts one of the government's biggest tools for cutting gasoline use and tailpipe pollution.

The numbers show just how far the reset goes. The Biden administration had pushed automakers toward a fleetwide average of 50.4 miles per gallon by model year 2031; the new Corporate Average Fuel Economy (CAFE) rule cuts that target to 34.9 mpg, according to ABC News. Duffy said the change, paired with a reclassification of crossover SUVs that had been treated as light trucks, would shave roughly $1,300 off the average price of a new car. The administration also eliminated automakers' ability to trade emissions credits with each other, a Biden-era mechanism Republicans had long criticized.

Savings for automakers, questions for drivers

Detroit's carmakers welcomed the move. Ford said it appreciated the administration's effort to "align regulations with market realities," and General Motors said it supports "better align[ing] fuel economy standards with market realities" — a shift analysts estimate could save GM alone more than $20 billion in compliance costs through 2031. But Time notes that economists are skeptical drivers will see the savings passed on to sticker prices, and the government's own National Highway Traffic Safety Administration projected the loosened standards would cost the average driver roughly $1,400 more in fuel over a vehicle's lifetime. University of Michigan engineering professor Anna Stefanopoulou told Time she "highly doubts" manufacturers will cut prices rather than lean into "larger and more profitable trucks."

The rollback is the latest in a string of Trump administration moves unwinding Biden-era clean-vehicle policy, following last year's elimination of EV tax credits and fuel-economy penalties, and February's repeal of separate EPA tailpipe emissions standards.

"Americans need relief from high costs, but instead Trump is giving automakers a free pass on pollution and handing families the bill — at the pump and with their health," the Sierra Club said in a statement announcing plans to challenge the rule in court.

The Natural Resources Defense Council also condemned the rule, arguing it will let automakers sell more gas-guzzling models and ultimately push fuel costs higher for consumers, according to a statement the group posted on its website. The Center for Biological Diversity separately criticized the administration for deprioritizing environmental protections in the rule.

The new standards apply retroactively to model years 2022 through 2031, according to Roll Call, and are expected to take effect in the coming weeks barring a successful legal challenge. With the Sierra Club and other environmental groups signaling lawsuits are imminent, the rule's fate — and whether drivers ultimately see cheaper cars or costlier fill-ups — is likely to be fought out in federal court well before the 2031 target year arrives.