The Environmental Protection Agency says it’s “fixing” widely despised technology that briefly turns off the engines of cars when they stop at stoplights and in heavy traffic.

Administrator Lee Zeldin posted on X on Monday morning that the EPA is reviewing the widely deployed systems. “Everyone hates it, so we’re fixing it,” he says.

The systems automatically shut off the engine when a car is idling and restarts it when drivers take their feet off the brakes. The devices are intended to help improve fuel economy and reduce greenhouse gas emissions.

The EPA says the fuel economy gains are 4 percent to 5 percent and provide the biggest benefit in conditions where the engine would otherwise be idling, such as stop-and-go city driving.

They are not formally required by the federal government, as Mr. Zeldin alludes to in his post, but the agency has tightened fuel economy and emissions standards and the devices help car manufacturers reach those minimum requirements.

The technology has been widely adopted in American automobiles manufactured over the last decade. Less than 10 percent of cars had the systems in 2016, but that figure had grown to approximately 50 percent in new gasoline-powered vehicles by 2023, according to the 2024 EPA Automotive Trends Report.

Many cars have a switch that allows drivers to disable the technology, but in many cases those switches must be activated every time the driver turns on the vehicle, which many drivers find irritating.

The technology was first introduced in the European Union, which has stricter emission standards than America. Mr. Zeldin has not released any details on what the EPA plans to do, so it is unclear how any possible change in standards would affect car manufacturers.

Many X users are responding to Mr. Zeldin’s post with encouragement.

“Oh pretty please yes,” an X user, Ignatius L. Jackson, says. “It should be an option not a requirement.”

Another, Richard Bruce, says, “Now we need to allow dealers and aftermarket to sell by-pass solutions for current models with this feature so you can ‘opt-out’ and permanently disable/remove current stop/start on your vehicle.”

But some users are pushing back on the idea. “Start/stop tech saves fuel,” Richard Angwin says. “Zeldin’s rollback ignores real benefits for drivers and the planet, prioritizing industry over efficiency.”

Mr. Zeldin has promised a rollback in regulations at the EPA. He has announced the biggest deregulatory action in American history, saying it will save trillions of dollars in regulatory costs and hidden “taxes” on Americans.