Is stop-start technology really beneficial for your vehicle?

MINNEAPOLIS – A unique feature in newer cars has many drivers turned off, even though it's meant to save them money. 

As cars await green lights across the United States, many sit in silence with their engines taking a breather.

"At first it's a little unnerving," said Lisa Smude. "You get to a stoplight and all of a sudden your car like cuts off."

"I was like, 'Why is my car stopping,'" said Jon Mark.

They're just two of millions of drivers that have the stop-start feature, meaning when their vehicle comes to a complete stop, the engine turns off until the brake is released again.

It's technology with good intentions, like lowering emissions. But it's getting many bad reviews.

"We just disable it every time we're in the car," said Mark, a reaction many shared to WCCO on Facebook and Twitter.

Bob Larkin, the director of automotive service tech at Dunwoody College of Technology, says the technology doesn't really bother him. His wife, however, feels the opposite.

"She doesn't particularly care for it," Larkin said.

Does stop-start technology benefit gas mileage?

"As we're idling the car, we're just not getting any miles per gallon. All we're doing is consuming fuel," Larkin said.

Edmunds tested stop-start years ago. Two cars drove an 80-mile stretch that included several stops, once with the system turned on, and another time turned off. Both cars burned less fuel with the technology turned on and improved their gas mileage. 

"I've seen from as a little as 3% to as much as 10% or 12% fuel savings by shutting that vehicle off [when stopped]," Larkin said.

When will stop-start not turn on? Frigid mornings for one. The technology won't activate when the battery is weak and the engine hasn't warmed, or if the battery is working hard. 

"You have your fan on high, your wipers on, your lights on," Larkin said.

Stop-start has the ability to sense if you're on hilly terrain and it will not activate. It also won't kill the engine when you're in reverse.

Does stop-start put wear on the starter or engine?

"[Manufacturers have] taken this into account engineering that vehicle. They know it's gonna be start stopped," Larkin said.

Similarly, the engine components are better designed for the constant on-off cycle, meaning it won't lose oil pressure over being turned off for several seconds.