The National Highway Traffic Safety Administration finalized a rule on September 28, 2026 that lowers how much fuel new cars and light trucks sold in the United States will be required to save. Under the new standard, the industry-wide average a manufacturer's fleet must reach by 2031 is 34.9 miles per gallon. The rule it replaces, written under the Biden administration, had put that figure at 50.4 mpg.
For scale: the American fleet averaged roughly 30.1 mpg in 2024. The old rule asked the industry to add about 20 mpg over seven years. The new one asks for fewer than five.
What changes, and when
The corporate average fuel economy program — CAFE, in Washington shorthand — does not set a floor for any individual car. It sets an average across everything a manufacturer sells, which is why a company can keep building large pickups as long as it sells enough efficient vehicles alongside them. Lowering the average lowers the number of efficient vehicles a company needs on the lot to stay compliant.
NHTSA is also changing how vehicles are sorted into classes for the purposes of that calculation, an adjustment that takes effect in 2030. It sounds technical, and it is, but which class a vehicle falls into determines the target it gets measured against — so reclassification can move a company's compliance position without a single engineering change.
The administration's case
Transportation Secretary Sean P. Duffy framed the rule as a cost-of-living measure. "This administration is delivering relief to families and reviving the beating heart of American manufacturing," he said. Of the standard being replaced, Duffy said the department had ended what he called an illegal mandate that pushed automakers into building more expensive electric vehicles that American families did not want.
NHTSA Administrator Jonathan Morrison added a safety argument to the price one: "Newer cars are safer cars. By reducing vehicle prices, more American families will be able to afford newer vehicles."
The department puts the saving at up to $1,300 on the average new vehicle, and $138 billion across five years.
The objections
The counter-argument is that the sticker price is not the whole price. A car that burns more fuel costs more to run, and gasoline was averaging about $4.47 a gallon when the rule was announced — a level at which the gap between 35 and 50 mpg shows up in a household's monthly budget rather than only in a regulatory filing.
Gina McCarthy, who led the Environmental Protection Agency under Barack Obama, put it in industrial terms: "Rather than keeping the U.S. at the forefront of innovation ... this administration has chosen to do the opposite." The Sierra Club argued that less efficient vehicles mean "more gas burned, spending more at the pump, and dirtier air." Dave Cooke, of the Union of Concerned Scientists, described the decision as a handout to automakers and oil companies.
Analyses of the rule project higher output of carbon dioxide, soot and smog-forming pollutants than under the standard it replaces, for the straightforward reason that a fleet burning more fuel emits more of all three.
Where the industry stands
The automakers are on the administration's side of this one. The Alliance for Automotive Innovation, the industry's main trade group, called the rule an "appropriate course correction" that brings the standards closer to what Americans are actually buying. Ford, General Motors and Stellantis all supported the change.
That alignment is itself a summary of the last two years in the American car market. Manufacturers committed heavily to electric capacity on the assumption that regulation would force the transition on a fixed timetable, and have spent the period since trimming those plans as the timetable moved the other way. The rule finalized this week removes most of what was left of the deadline.
Reporting from PBS NewsHour, ABC News and Democracy Now!
