EPA Is 'Fixing' Start/Stop Tech, Agency Admin Says

Yahoo

12-05-2025

Start/stop technology is one of the more divisive fuel-saving strategies manufacturers use, and now EPA administrator Lee Zeldin is targeting it, per a post on X Monday morning.
If you're looking for additional details of what Zeldin means by 'fixing it,' we're afraid they're not available as of yet. Road & Track reached out to the EPA to learn more, but hadn't received a response by the time this story was published.
Zeldin says in his post that companies 'get a participation trophy' from including start/stop tech in vehicles. Of course, that's not technically what's going on here, but the EPA does offer car makers something called 'off-cycle credits' that incentivize the use of start/stop technology, amongst other things that aim to reduce vehicle emissions. Here's what the EPA has to say about the tech as of today on its website.
'Start-stop systems (sometimes called idle-stop, smart start, or other manufacturer-specific names) save fuel by turning off the engine when the vehicle comes to a stop and automatically starting it back up when you step on the accelerator. Start-stop can improve fuel economy by 4%–5% and provides the biggest benefit in conditions where the engine would otherwise be idling, such as stop-and-go city driving.'
Does start/stop tech actually reduce fuel consumption, though? One real-world test from Jason Fenske's Engineering Explained showed there is a benefit to the tech when you're sitting stationary for extended periods of time, such as at a long traffic light. If you're only stopping briefly, however (like for a stop sign), the benefit drops away.
It's also important to recognize that not all start/stop systems are the same. Many traditional internal-combustion cars with the tech will shut the engine off when you've come to a full stop, then switch the engine back on once you lift off the brake pedal to begin moving again. Vehicles with mild-hybrid electric assist will take that a step further and shut the engine off as you're coasting to a stop, eliminating the rough sensation of an engine abruptly stopping. They're typically much smoother on start-up, too, as the electric assist gets you moving off the line, giving the engine a chance to start after the car's already started to roll forward. Many mild-hybrid-equipped vehicles will even shut the engine off while coasting, too, silently saving fuel in the background.
Where this ultimately leads is unclear at the moment. Even if the EPA eliminates any incentives to include start/stop on cars, there's no guarantee that car companies will drop the technology.
Car manufacturers are in no way required to include start/stop technology on their vehicles, and virtually every new car on sale today that has it allows you to turn it off. The one annoyance commonly voiced by folks is that many of those vehicles will force you to stab the 'off' button on every key cycle because it defaults to on.
We'll update this story with any developments if and when the EPA provides additional details.
You Might Also Like
You Need a Torque Wrench in Your Toolbox
Tested: Best Car Interior Cleaners
The Man Who Signs Every Car