U.S. Rolls Back Fuel Economy Standards, Opening the Door to Billions More Gallons of Gas

Washington has finalized a major softening of corporate average fuel economy requirements, cutting the fleet-wide target for light-duty vehicles to 34.9 mpg by 2031 — down sharply from the 50.4 mpg goal set under the previous administration. The new figure represents only a modest step up from the 30.4 mpg already required in 2024, and plenty of hybrids and plug-in hybrids on dealer lots today already beat it comfortably.

According to the government’s own 892-page assessment, the looser rules carry real consequences. By 2050, additional gasoline burned could range from 36 billion gallons in the mildest projection to 128 billion in the worst case, with a mid-range estimate near 122 billion gallons. Emissions by 2035 could climb by an amount equivalent to putting roughly 17 million more cars on the road, and the agency acknowledges that adverse health effects from pollutant emissions are expected to rise nationwide. Formaldehyde output could grow by as much as 12.6%, while outside groups cited in the ruling project CO2 increases on the order of a billion metric tons by 2050.

Officials framed the change as relief for buyers, saying reduced compliance pressure would trim average upfront vehicle costs by about $1,290 as automakers lean on cheaper engine technology instead of efficiency gains or electrification. The lobbying group representing Ford, GM, BMW and others welcomed the move, arguing the prior targets effectively pushed a switch to EVs that didn’t match customer demand. Environmental advocates fired back, warning that less efficient cars mean more spending at the pump and dirtier air in communities.

The rollback is the latest in a series of federal moves away from electrification, following the end of the $7,500 consumer tax credit and the removal of penalties for missing previous targets. Automakers could still choose to sell cleaner vehicles on their own — hybrids already claimed a record 16.3% of the market in the second quarter — and a future administration could tighten the rules again. But cars built under the weaker standards will stay on the road for decades, and the fuel burned and pollution released in the meantime won’t be easily undone.