On Saturday, Donald Trump announced on Truth Social that he had approved new gas-mileage rules for new cars and trucks — rules that let automakers sell far less fuel-efficient vehicles than the law had required.

"I have just approved new Fuel Economy Standards that TERMINATE Sleepy Joe Biden and Pete Boot-EDGE-EDGE's ridiculous EV Mandate," he wrote. The new rules, he said, mean "LOWER PRICES."

His own government's numbers tell a less flattering story. According to the Transportation Department's own analysis of the proposed rule, reported by The Washington Sun, the change means cars that burn more gas and a country less able to handle spikes in oil prices.

And he did it in the middle of one.

What the rules do

Since the 1970s, the federal government has required automakers to make the cars and trucks they sell more fuel-efficient on average over time. Those rules have doubled the average miles per gallon of American vehicles.

The rules on the books aimed to get new cars to 50.4 miles per gallon by 2031. The Trump administration's plan, as proposed in December, cuts that target to 34.5 miles per gallon. According to The Washington Sun, that's lower than the average fuel economy of the existing U.S. fleet as of 2024.

In plain terms: the new "goal" is worse than where we already are.

The rules were built for exactly this moment

The first gas-mileage rules were a response to the 1973 oil embargo. Gas prices were soaring, oil supplies were blocked, and there was conflict in the Middle East. Congress and President Gerald Ford acted to make the country less dependent on foreign oil.

That describes 2026. Trump's war with Iran and the closure of the Strait of Hormuz have pushed up what Americans pay at the pump. We've already reported that six months of the Iran war has cost the average household about $1,200.

"I feel like we're reliving exactly the moment that they were designed for," Dave Cooke, who studies fuel efficiency at the Union of Concerned Scientists, told The Washington Sun.

Cars that burn more gas make every future oil shock hurt more. The administration's own analysis says so: the energy-security benefit of using less fuel shrinks as cars get less efficient, and the risk to the economy from global oil shocks goes up.

"Lower prices" — says who?

The White House claims the old rules would have added nearly $1,000 to the price of a new car.

But you don't just pay for a car once. You pay to fill it up for years. The National Highway Traffic Safety Administration's own analysis estimates a 2031 car would burn about $1,400 more in gas over its life. The same analysis says lower sticker prices and other savings roughly cancel that out for the buyer — so the real case against these rules isn't the car payment. It's everything else the analysis found: the country more exposed to oil shocks, about 7,000 fewer auto industry jobs by 2031, and more pollution-related illness.

Since the rules were strengthened under President Obama, they have saved drivers more than $300 billion in fuel costs, Cooke said.

The same analysis says dirtier cars bring more health problems from pollution: more ER visits, worse asthma, more heart attacks and more early deaths.

Part of a bigger push

This is the culmination of a long campaign. According to The Washington Sun, Trump has ended the tax credits for electric vehicles, blocked California's stricter clean-air rules, and thrown out the 2009 scientific finding that vehicle pollution rules were built on. He also signed a law that cut the fine for breaking the gas-mileage rules to $0 — so even the old rules had no teeth.

Republicans in Congress helped. We covered the Republicans who led the resolutions to kill California's clean-air rules in 17 states.

What we know

With gas prices driven up by his war with Iran, Donald Trump approved new rules cutting the fuel-economy target for new cars from 50.4 to 34.5 miles per gallon, as proposed — below the 2024 average of the existing U.S. fleet. His own government's analysis says a 2031 car would burn about $1,400 more in gas over its life, the country will be more exposed to oil shocks, thousands of auto jobs will disappear, and pollution-related illness and early deaths will rise.

Source

Trump Says He Has Reversed Biden-Era Fuel Efficiency Standards — Mara Hoplamazian, The Washington Sun, September 26, 2026.