EPA takes aim at start-stop systems in cars, calls feature a 'climate participation trophy'

The Environmental Protection Agency is proposing to roll back federal incentives for automatic start-stop technology in new vehicles.

EPA administrator Lee Zeldin announced the move Monday on social media, calling start-stop systems a “climate participation trophy” that most drivers dislike.

“EPA approved it, and everyone hates it, so we’re fixing it,” Zeldin posted on the social media platform X.

What is start-stop technology?

The system automatically shuts off a vehicle’s engine when it comes to a complete stop—like at a red light or in traffic—and restarts when the driver lifts their foot off the brake or taps the accelerator.

While not required by law, the feature became widespread due to fuel economy credits granted under federal emissions rules. Start-stop systems are considered an “off-cycle” emissions-reduction technology, meaning they provide benefits not measured during standard testing procedures.

The incentive was created more than a decade ago as part of federal emissions and fuel economy standards, which aimed to reward automakers for adding technologies that cut pollution in ways not captured by traditional testing. Start-stop systems are one of several features that qualify.

At the time, start-stop was used in less than 1% of new vehicles. By model year 2021, it had grown to 45%, according to the EPA. Other estimates, including industry surveys, place current adoption closer to 65%.

Do start-stop systems actually help?

Supporters say the technology can reduce fuel consumption in city driving and lower greenhouse gas emissions. According to the Battery Council International, start-stop systems helped eliminate nearly 10 million tons of emissions in 2023 alone.

Tests by the Society of Automotive Engineers show the feature can improve fuel economy by 7% to 26% in stop-and-go traffic. However, the benefits are minimal for highway driving.

Why is it unpopular?

Despite environmental benefits, many drivers find start-stop systems irritating. Common complaints include the jarring feel of the engine shutting off and restarting, sluggish acceleration, and reduced air conditioning performance when the engine is off.

Some critics also argue the feature causes extra wear on engines and starter systems, though automakers say they designed these systems to withstand frequent use.

While many vehicles offer a button to disable start-stop, the setting typically resets to “on” each time the vehicle restarts. Some models don’t offer an off switch at all, leading some drivers to turn to aftermarket software to disable the feature, raising concerns about warranty and emissions compliance.

What happens next?

The EPA’s proposal would not ban start-stop systems but would eliminate the incentives that reward automakers for including them.

It’s the latest step in a broader deregulatory effort under the Trump administration, which has pushed to reduce federal climate-related mandates and review existing environmental rules.

It remains unclear whether automakers will continue to install the systems without the added credits. The Alliance for Automotive Innovation, an industry trade group, did not immediately respond to a request for comment.