Would you be willing to pay more for gas if your car could be a little less annoying?
If you’ve ever noticed a gas-powered engine shutting off during a red light, that’s the start-stop feature. Its adoption has skyrocketed since 2012, when the Environmental Protection Agency started subsidizing the feature with credits to manufacturers.
But under the Trump administration, the agency is threatening to eliminate those credits. In a post on X, the agency’s administrator, Lee Zeldin, said that start-stop technology was just a “climate participation trophy” for companies, and that “everyone hates it.”
Though the technology has its skeptics, research says it does effectively cut fuel consumption and emissions. Most studies on start-stop technology show real-world fuel use reductions of 5 to 10 percent, depending on driving patterns. One study found that start-stop begins to save fuel when the engine is off for as little as seven seconds during an idling period.
But if the E.P.A. ends its credits, could it spell doom for the feature? And where would that leave automakers and drivers?
Just how annoying is start-stop?
Most of the complaints fall in a few categories. Some skeptics believe that it doesn’t really save on gas, or that it adds wear and tear to the engine. Others worry about not having control of the car, or about having the air-conditioning turn off with the engine on hot days.
Manufacturers try to make the feature as seamless as possible. That might mean turning off the engine only during longer stops, or only if the air-conditioning isn’t drawing too much energy. Newer cars also have starter systems specifically designed for start-stop.
But that effort hasn’t quite made the feature beloved by everyone. In many models, it’s hard to miss when the engine shuts off and turns back on. Several tutorials on YouTube showing how to disable the feature have amassed over a million views.
In most cars, drivers can press a button to turn off the feature for their current trip, but companies can’t make the switch permanent without losing eligibility for the credit.
Matt Preuss, a former car technician, created an aftermarket device called the Idlestopper that permanently disables the start-stop feature.
“If it was more user-friendly, and maybe if a customer could predict when it would happen, they would be more comfortable with it,” Mr. Preuss said.
First impressions are also lasting. Joshua Linn, a professor at the University of Maryland who studies vehicle emissions standards, said the early implementations of the technology were more likely to have problems.
Start-stop safety complaints collected by the Department of Transportation reached a peak in 2022, with cars around the 2017 model year being the most likely to have reported problems. In 2022, over 1 percent of all automobile defect complaints in the agency’s database were related to start-stop, though by 2024 that percentage fell almost in half even as the feature was added to more cars over that time.
“What happens with a lot of these technologies is there’s some kinks in the beginning, and we work it out and things are better,” Mr. Linn said. “Stop-start, I think, is an extreme example.”
The rise of fuel-saving technology
Here’s how the E.P.A. credits work: Manufacturers are fined if their yearly emissions average of new vehicles is too high, as measured in grams of CO2 per mile. Emissions tests are conducted by running the cars on giant treadmills, but some features (like headlights) are turned off during these tests. This means there’s a mismatch between real-world driving and the lab tests, and so a small credit against the emissions limit is given for certain “off-cycle” features like LED headlights or start-stop.
Putting a number on how much these credits are worth is challenging because manufacturers may value them differently based on their current fleet average. David Greene, a professor of civil engineering who has advised the NHTSA on fuel standards, said a good “ballpark” estimate prices the start-stop credit at about $30 per car to a company. Another way to think of it: For a fleet of 500,000 new cars, receiving the start-stop credit for every car could give a company a $15 million buffer from any emissions fines.
Many other features in your vehicle are incentivized by these credits — you just may not notice them all.
But how responsible are the credits for increased adoption? It’s hard to say: Early adoption in the U.S. started before the credit was given out, and car companies have other incentives to increase fuel efficiency.
Some technologies with credits have also been adopted more than others. Solar reflective coating, which lowers the need for air-conditioning, has grown to only 14 percent from 11 percent in the last six years among all cars (not just combustion engines). But “active aerodynamics” technology to reduce drag has gone to 60 percent adoption from 30 percent in the same time.
Peter Slowik of the International Council on Clean Transportation says the credits are most useful at the early stages of newer technologies, and much less so once features are commonplace, becoming essentially “free credits to the automakers.”
What happens if the E.P.A. kills the credit?
Mr. Zeldin has said eliminating the start-stop credit would allow drivers to opt out of the “single worst feature in their motor vehicle.” But that might not mean the end of the feature, since manufacturers could still choose to include start-stop even without the credit. When asked for more details, E.P.A. spokesman Mike Bastasch said to “stay tuned for more information about how E.P.A. intends to address this issue.”
A broader question is how manufacturers will respond if the Trump administration loosens overall emission reduction targets. The yearly reductions in emissions targets were set at a more aggressive rate during President Biden’s term than during the Obama and Trump administrations.
For the E.P.A. to put in a rule change, it must first have a public comment session, expected to open this summer. Passage of the rule could take years.
That’s true if the E.P.A. wants to change overall emission targets or end the off-cycle credits for start-stop.
David Cooke of the Clean Transportation Program says that regardless of what the E.P.A. does, keeping start-stop is a “no-brainer” for manufacturers: It costs a small amount to implement, and it results in considerable fuel savings, which is a selling point to customers.
Start-stop would also help manufacturers stay under the emissions limit even if the off-cycle credits are canceled. That’s because the standard treadmill tests capture some — just not all — of the feature’s real-world savings. So car companies would still have reason to include the technology. In Europe, and most other countries, start-stop technology is considered standard. In the United States, each automaker has adopted the feature at different rates. Volkswagen received the stop-start credit on 95 percent of its internal combustion cars sold in America, while Mazda received it for just 5 percent.
Rasto Brezny, executive director of the Manufacturers of Emissions Controls Association, said he couldn’t predict if getting rid of the credit would change the number of cars with start-stop. But he did note that regulation has always been the driver of clean technology: “Nobody would put a catalytic converter on a vehicle unless they had to.”
Ben Blatt is a reporter for The Upshot specializing in data-driven journalism.
The post Should the Government Stop Subsidizing a Car Feature That ‘Everyone Hates’? appeared first on New York Times.
