Over the years, one urban fuel-efficiency myth has been pervasive—that you'll save gas by letting your car idle rather than shutting the engine off when, say, waiting at the curb for someone running into a store. Popular Mechanics, AAA, and others have busted this myth, pointing out that a vehicle gets negative miles per gallon while idle. The consensus advice now is that if you car is stopped for more than a minute, the smart move is to turn the engine off.
The arrival of auto stop-start, a technology most often seen in hybrids, does this work for you, and not only if you're idle for minute or more. As the name suggests, the tech shuts off the vehicle's engine automatically when the car comes to a stop—at a red light, say—and then starts it again in the jiffy when the driver takes a foot off the brake pedal.
The technology has slowly been spreading beyond hybrids to a few vehicles powered by traditional internal combustion engines, and new research from AAA indicates that this is a good thing. After testing several cars with the feature, researchers concluded that the tech is a no-brainer that saves drivers 5% to 7% on gas costs annually. A blurb from the press release explains a little more about what this means to us all:
“Up to seven percent improved fuel economy can mean a $215 annual fuel savings for Southern California consumers,” says Steve Mazor, the chief automotive engineer of the Auto Club’s Automotive Research Center. “It also reduces the main greenhouse gas emitted from cars (CO2) by 5 to 7 percent in city driving.”
Navigant Research predicts that by 2022, 55 million cars sold annually will have stop-start technology, up from 8.8 million last year. Adoption is ahead of the curve in Europe, where gas prices are astronomical compared to much of the world: Roughly 45% of cars built in Europe already come with start-stop systems.
In the U.S., meanwhile, the stop-start feature remains an anomaly; only about 500,000 new cars sold in the U.S. in 2013 had the technology. Estimates call for that figure to shoot up to 7 million by 2022. But there's no need to wait. The vehicles below already offer stop-start as an option or a standard feature in the U.S.:
BMW: Several BMWs have auto start-stop technology, but not all drivers are fans. "The stop-start system is just awful," one Automotive News columnist wrote of his 2012 328i, describing the herky-jerky feeling of stepping off the brake and automatically restarting the engine as "balky" and "uncomfortable." Drivers do have the option to turn the start-stop feature off if it's proving to be too annoying.
Chevrolet Impala: The automaker has made stop-start technology standard on the 2015 Impala.
Chevrolet Malibu: Starting with the 2014 model year, Chevy made stop-start standard on the Malibu, which the automaker says has helped it boost fuel efficiency by 14% with city driving.
Ford Fusion: A couple of years ago, Ford introduced a stop-start system as a $295 option for the first time in the U.S. on a non-hybrid model. At the time, the automaker estimated that drivers would save $1,100 in gasoline costs over five years of driving by upgrading to stop-start. The 2015 Fusion is estimated to get an extra 3 mpg over the base model.
Ford F-150: Buyers who go for the 2.7-liter EcoBoost engine on the 2015 version of Ford's best-selling pickup get a special auto stop-start feature that's a little different than others out there. Like other systems, this one automatically shuts off the engine as a fuel saver when the vehicle is stopped, but not when the vehicle is towing something or when it's in four-wheel drive. Without that feature, the tech could prove frustrating for pickup drivers who are hauling something in the rear or are inching along stop-and-go on bumpy or muddy terrain. During all other driving situations, "The engine restarts in milliseconds when the brake is released," Ford promises.
Porsche: Among the Porsche models that come with auto start-stop, the new Panamera's system is special in that the engine not only shuts off when the vehicle is at a full stop—but it also shuts off when the car is slowing down approaching a traffic light. While the engine goes quiet, climate control, audio systems, and other interior features remain powered by the battery. And if the battery doesn't have enough juice for all the auxiliary equipment, the engine will simply turn back on.
Ram 1500: The 2013 model year Ram truck offered start-stop technology as an option, the first in the pickup category to do so. "This new system is just one of the advances that allow the 2013 RAM 1500 to offer up to 20 percent greater fuel efficiency than previous models," the automaker stated.