Regardless, start-stop is destined to be on the majority of cars in the next few years. Ford now has it as a standard feature on its Escape and Focus vehicles, and on some engines in its top-selling F-150 pickup trucks. Eventually, 70 percent of Ford’s models will offer it, Mr. Fascetti said.

By the 2018 model year, all Buicks will come equipped with the technology. Currently Buick’s Encore and Envision offer it. In addition, it is available on several models from Cadillac and Chevrolet, including the ATS, Cruze, Impala and Malibu.

At Fiat Chrysler, the Pacifica offers the technology, and “the majority of our vehicles will have it over time,” said Mike Duhaime, a Fiat Chrysler powertrain director.

Still, not many Americans have yet experienced the technology. And despite its environmental and fuel-saving benefits, many who do have it, like Dr. Tao, don’t like it.

“Our primary research says almost to a person, people say they turn off their stop-start systems,” said Tim Barnes, a director of product planning for Mazda in the United States.

That’s one of the reasons that Mazda has no plans to introduce the technology in the United States, even though Mazda has been offering it in Japan since 2010.

For the technology to work for consumers, the experience needs to be seamless, manufacturers say.

“Restarts must be fast, smooth, with no noise and little vibration,” said Ulrich Muehleisen, head of marketing and product development for Robert Bosch, a company that has sold 15 million start-stop units in Europe since 2007.