With the war with Iran continuing to drive up U.S. fuel prices, the Trump Administration softened vehicle efficiency rules for automakers this week.

The new rules released Sept. 28 require car and truck manufacturers to make their fleets 1 percent more efficient each year, targeting 34.9 miles to the gallon by 2031, according to NPR. The Biden Administration in 2024 had updated these Corporate Average Fuel Economy (CAFE) standards to require fleets to be 2 percent more efficient each year, aiming for 50.4 miles to the gallon by 2031.

The Trump Administration made this change with U.S. gasoline prices averaging $4.41  per gallon this week, up from $3.16 a year ago, according to AAA data. Average diesel prices dropped slightly to $6.39 from a record high of $6.53 on Sept. 22.

The more stringent fuel economy standards were expected to save passenger car and light duty truck owners more than $600 million over the lifetime of their vehicles, according to the National Highway Traffic Safety Administration.

Since their adoption by Congress in 1975, CAFE standards have saved drivers a combined $5 trillion in fuel costs and avoided 14 billion metric tons of climate-warming carbon dioxide emissions, according to a Princeton University study.