Opinion: The new fuel-economy rules bet on cheap gasoline that may not last

The National Highway Traffic Safety Administration signed a final rule on September 25 and released it Monday, September 28, gutting the fuel-economy targets automakers must meet for the rest of the decade. Required annual efficiency gains fall from roughly 2 percent to about 1 percent, and the industry-wide target for model year 2031 drops to an estimated 34.9 miles per gallon, down from the 50.4 mpg standard finalized under the Biden administration. The rule also ends the ability of manufacturers to trade fuel-economy credits with one another starting in 2028, a mechanism Republicans had long criticized as a backdoor subsidy for electric vehicles. Coverage of the rule from National Public Radio and ABC News captures both the scale of the change and the divided reaction it has produced.

Taken on its own, a fight over corporate average fuel economy numbers can sound like a technocratic squabble over a regulatory formula few drivers ever think about. It is not. This rule is the third leg of a deliberate, sequenced effort to dismantle federal authority over vehicle emissions, and it deserves to be judged as such: not as an isolated tweak to a mileage chart, but as a bet that cheap gasoline and a friendlier legal landscape will outlast the consequences of removing the guardrails altogether.

A rollback built on a rescinded foundation

The mileage rule did not arrive out of nowhere. In July, the administration used the One Big Beautiful Bill Act to zero out the civil penalty automakers pay for missing CAFE targets, which had already made the Biden-era numbers largely unenforceable in practice. Then, in February, the Environmental Protection Agency finalized its rescission of the 2009 greenhouse-gas endangerment finding, the predicate the agency has relied on since Massachusetts v. EPA to regulate tailpipe carbon dioxide under the Clean Air Act. Without an endangerment finding, EPA has taken the position that it lacks statutory authority to set greenhouse-gas standards for vehicles at all, effectively retiring its own half of the two-agency system that has governed fuel economy and emissions since 2010.

Administrator Lee Zeldin has not been shy about the ambition behind that move. The agency's own materials describe it in stark terms:

"This is the single largest deregulatory action in U.S. history and will save Americans over $1.3 trillion," EPA said in announcing the rescission, a framing the agency and the White House repeated when Zeldin and President Trump touted the action together.

The irony is that the legal doctrine EPA is now walking away from was not handed down by a hostile court forcing the agency's hand. It was won by the government's own side. In the 2007 case that created the endangerment-finding framework, the Supreme Court held in Massachusetts v. EPA that carbon dioxide fits the Clean Air Act's definition of an air pollutant and that EPA must ground any refusal to regulate it in science, not policy preference. Rescinding the finding rather than defending it in court is a legitimate use of the rulemaking process, but it is also a tell: an administration confident its reading of the underlying science and law would survive judicial review would have less need to erase the finding altogether rather than simply decline to act on it.

The savings math carries an asterisk

The Department of Transportation's public case for the rollback rests on affordability. Officials project roughly $138 billion in savings over five years and about $1,300 off the price of an average new vehicle, and General Motors alone is expected to avoid $20.4 billion in compliance costs through 2031, with industry-wide technology-cost savings estimated near $60 billion. The Alliance for Automotive Innovation, the trade group representing GM, Toyota, Ford, Hyundai, Volkswagen and other major manufacturers, welcomed the rule as aligning standards "with the law and current market conditions," arguing the prior targets amounted to a de facto electric-vehicle mandate out of step with consumer demand.

That framing counts only one side of the ledger. The entire logic of fuel-economy standards is that upfront technology costs are recovered, with interest, at the pump over a vehicle's life. Lowering the mileage bar does not make gasoline cheaper; it makes vehicles thirstier for however long owners keep them, which for the median new car is a decade or more. Whether that trade nets out in drivers' favor depends heavily on future gas prices, and 2026 has been a poor year to bet on those staying low. The national average spiked toward $4.55 a gallon earlier this year after the closure of the Strait of Hormuz, a reminder that fuel costs are exposed to geopolitical shocks in ways a vehicle's certified mileage rating is not. A rule that reduces required efficiency just as the case for efficiency as insurance against volatile fuel prices is strongest is, at minimum, oddly timed.

States and courts are not finished with this fight

The rollback also lands in the middle of an unresolved jurisdictional battle. Congress used the Congressional Review Act last year to revoke the Clean Air Act waivers that let California set vehicle-emissions standards tighter than the federal floor, waivers more than a dozen other states had adopted by reference; President Trump signed those resolutions into law in June 2025. The Justice Department followed this March with a lawsuit challenging California's zero-emission-vehicle mandate directly. Twenty-one state attorneys general, along with several cities and a county, are on record opposing the CAFE rollback as unlawful and harmful to consumers, a position California Attorney General Rob Bonta reiterated in formal comments to NHTSA, and that Maryland Attorney General Anthony Brown's office detailed in describing the multistate coalition's objections.

• NHTSA's new target: roughly 34.9 mpg industry average by model year 2031, versus 50.4 mpg under the prior rule.
• Required annual efficiency gains cut from about 2 percent to about 1 percent, with inter-manufacturer credit trading ending in 2028.
• DOT projects $138 billion in savings over five years; GM alone expects $20.4 billion in avoided compliance costs through 2031.
• Twenty-one state attorneys general, four cities and a county have formally opposed the rule as unlawful.

None of this means the prior standards were beyond criticism. A 50.4 mpg target reached partly through electric-vehicle credit trading did strain automakers' product plans, and reasonable people can disagree about how fast a mandate should push a market that still depends on charging infrastructure many buyers do not yet have. But there is a difference between recalibrating a target and dismantling, in the space of seven months, both the target and the legal authority that would let a future administration reinstate one without starting from zero. That is what has actually happened: a statutory penalty zeroed out in July, an endangerment finding rescinded in February, and now a mileage rule rewritten on the assumption that the finding is gone for good.

A trade that shifts risk, not just cost

The honest description of this policy is not that it saves Americans money outright. It is that it shifts financial and environmental risk from automakers' balance sheets, where it was concentrated and predictable, onto individual drivers' fuel budgets and the broader climate system, where it is diffuse and, as this year's gas-price swings showed, considerably less predictable. Consumers who buy a less efficient vehicle in 2031 because the rule allowed it will not get to renegotiate their fuel costs if prices rise again. And a legal foundation demolished rather than defended in court leaves the next administration, and the next Congress, to rebuild from scratch rather than adjust from an existing baseline, guaranteeing that vehicle-emissions policy keeps lurching between opposite poles every time power changes hands. That instability, as much as the mileage number itself, is the real cost of Monday's rule, and it is one that will not show up in any DOT press release.