That silence you hear? It's a month's worth of payments on the family car-insurance plan not being spent on an idling engine. That's one way to look at new numbers out from the AAA that say stop-start engine technology will save drivers a solid chunk of change in the form of lower refueling costs. If only more automakers would embrace the tech for their vehicles.

AAA says a typical US driver can save $179 a year if they drive a car with a stop-start system, which automatically shuts off the engine when the car's not moving. By typical, AAA means a driver putting 15,000 miles a year on a car that gets 20 miles per gallon. AAA figured this out by running a commuter simulation with a 2013 Ford Fusion, a 2014 Mercedes Benz CLS550 and a 2013 Chevrolet Malibu.

Hybrid Cars noted in 2011 that as much as 42 percent of new vehicles in 2016 would offer start-stop technology, and the lack of incentives prevented that number from being higher. Part of the problem with introducing the technology to the US is that the EPA's testing methods don't factor in real-world driving factors (yet) that can be boosted by stop-start technology. Therefore, the current tests underestimate the technology's fuel-saving benefits.

The lack of incentives appeared to take hold, as the US didn't get its first midsize family sedan with stop-start technology until the 2013 Ford Fusion offered it as a $295 option in the fall of 2012. Ford estimated at the time that the stop-start-equipped Fusion would save drivers about $220 a year in refueling costs relative to other midsize sedans, making it a good investment. Chevy now offers stop-start standard in some versions of the 2015 Impala.

Late last year, German automotive component maker Bosch estimated that stop-start systems may cut fuel use by about 10 percent. Bosch made that claim right after Mercedes-Benz parent Daimler said the EPA was underestimating fuel economy achieved by its sedans equipped with stop-start. Check out AAA's press release below.
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AAA's Tests Reveal Real-World Benefits of Automatic Stop-Start Technology

Research yields up to seven percent mpg improvement and CO2 reduction

ORLANDO, Fla., July 24, 2014 /PRNewswire-USNewswire/ -- New research from AAA shows that automatic stop-start automotive technology delivers a significant fuel economy benefit. Test results indicated that automatic stop-start systems provide a five percent to seven percent improvement in fuel economy and reduction in carbon dioxide emissions compared with tests conducted on the same vehicle with the automatic stop-start system disabled.

AAA tested three vehicles equipped with automatic stop-start systems using the EPA's "urban" driving cycle. With the automatic stop-start system engaged, the vehicles delivered improved fuel economy of up to seven percent over tests with the automatic stop-start technology disengaged.

Based on these findings, these systems can improve fuel economy, saving motorists up to $179 in annual fuel costs, based upon driving 15,000 miles a year in a vehicle that gets 20 mpg with fuel prices at $3.65 per gallon.

"Up to seven percent improved fuel economy can mean a $179 annual fuel savings* for consumers," says Greg Brannon, Director of AAA's Automotive Engineering and Industry Relations team. "The technology requires only minor adjustment for motorists – automatic stop-start technology is simply applied to standard combustion engines."

Automatic stop-start systems turn off the engine when the vehicle is at a complete stop − such as in traffic or at a stoplight. When the driver releases the brake or the clutch, the engine starts and moves forward. While the engine is stopped, systems and gadgets run on power from the vehicle's battery. The feature most often deploys in city driving scenarios – versus highway operation – and may feel slightly different to motorists until they become accustomed to the automatic stop-start sensation. The benefits, however, will not be realized if the feature is turned off.

AAA put three automatic stop-start vehicles through the Environmental Protection Agency's "urban" cycle, which simulates a commuting trip covering 11.04 miles at an average speed of 21.2 miles-per-hour. The simulation is part urban driving – including frequent stops – and part highway driving. This test was selected to ensure that the stop-start systems had an opportunity to work as they would on a normal commute. A 2013 Ford Fusion, a 2014 Mercedes Benz CLS550 and a 2013 Chevrolet Malibu were tested. The AAA research was conducted with the Auto Club of Southern California's Automotive Research Center.

Automatic stop-start vehicles are still new to North American motorists, and drivers may not be familiar with the features and benefits of this technology. The U.S. Environmental Protection Agency and the National Highway Traffic Safety Administration have set standards to increase the Corporate Average Fuel Economy levels to 54.5 (approximately 40 window sticker) miles per gallon by 2025, giving automakers further incentive to escalate fuel-saving technologies. Navigant Research's 2013 automatic stop-start vehicles assessment projects that only 500,000 of the vehicles sold in the United States in 2013 included an automatic stop-start system, but that number could exceed seven million by 2022.

Additional information regarding AAA's tests of automatic stop-start vehicles is available on the AAA Newsroom. The study is part of AAA's Driving Fuel Efficiency series, which also includes the electric vehicle climate study and future fuel-economy studies.

AAA's Automotive Engineering team conducts proprietary research to better understand consumer implications of automotive technology, design and functionality.

As North America's largest motoring and leisure travel organization, AAA provides more than 54 million members with travel, insurance, financial and automotive-related services. Since its founding in 1902, the not-for-profit, fully tax-paying AAA has been a leader and advocate for the safety and security of all travelers. AAA clubs can be visited on the Internet at AAA.com.

About AAA's Driving Fuel Efficiency Series: From driving tips that increase gas mileage to the latest fuel-saving automotive technology, AAA's Driving Fuel Efficiency series will reveal research findings and expert advice to help motorists make educated driving decisions.

*Fuel savings are based on driving 15,000 miles a year in a vehicle that averages 20 mpg with fuel prices at $3.65 per gallon. These savings do not include other factors relative to ownership costs of vehicles equipped with automatic stop-start systems, such as potentially higher costs to replace the upgraded battery or starter typically used in these vehicles.

AAA news releases, high-resolution images, broadcast-quality video, fact sheets and podcasts are available on the AAA Newsroom at newsroom.aaa.com.

Stay connected with AAA on the web via:
Twitter.com/AAAauto
Twitter.com/AAAnews
YouTube.com/AAA
Facebook.com/AAAfanpage
Facebook.com/AutoSkills

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    • 1 Second Ago
  • 12 Comments
      George Strickland
      • 4 Months Ago
      wouldn't want it on any vehicle and I see one manufacturer will offer it on a twin turbo vehicle,believe it will cause more harm than good.
      Rotation
      • 4 Months Ago
      I cannot see how this is true. We laugh about stop-start all the time on lunch runs. In an Audi or BMW the car usually doesn't turn off, it just says "can't turn off because the A/C is running" or such. And if it does turn off, it turns back on before the light changes because the A/C started running warm. Maybe in the spring and fall it would help when it isn't so warm. For the record, AAA's press release would imply they actually tested cars on the EPA test, not just did computer simulations.
        Danny G
        • 4 Months Ago
        @Rotation
        Maybe it's different because I drive a hybrid with a larger battery than a regular car, but my car turn off at just about every light and stop sign with the A/C on. And I live in Miami...
      Ryan
      • 4 Months Ago
      It should be mandatory by now, not an option. Or to put it a different way, only idiots would buy a car that doesn't have it when it is available. And it should be available on every car and truck.
      Actionable Mango
      • 4 Months Ago
      I've heard many times throughout my life, and most recently on NPR's "Car Talk", that the harshest wear on a motor by far is when it is being started and you would want to avoid buying, say, a pizza delivery car versus a car with the same number of miles, but all highway. So wouldn't Start-Stop greatly exaggerate that wear? Or is this mitigated with some sort of engineering solution? (Perhaps the oil pump is electric and it keeps running?)
        2 wheeled menace
        • 4 Months Ago
        @Actionable Mango
        They're probably referring to wear that happens when you first start the car up after having it sit for hours and hours - when the oil has settled and drained off or whatever. If you constantly stop and start in the city, i don't see this kind of wear being a big deal at all.
        Danny G
        • 4 Months Ago
        @Actionable Mango
        This. Cold starts are indeed harsh on engines, such as when you start your car in the morning or after work. With start stop the car is only off for anywhere between a few seconds and at most a couple of minutes. This means the engine stays around operating temp and like 2 wheeled menace said, the oil lubricating everything hasn't had time to go back into the oil pan.
      PeterScott
      • 4 Months Ago
      EPA doesn't underestimate, Manufacturers are just lobbying for more credit. This is only typically good for 1-2mpg unless you live in commuter hell. I do two kind of drives: Short errands where my car barely warms up enough as it is, and this system would be a detriment it triggered, and road trips where I seldom stop so this would be useless.
        Actionable Mango
        • 4 Months Ago
        @PeterScott
        My drives are exactly like yours, but most of the people I know do in fact live in commuter hell.
          PeterScott
          • 4 Months Ago
          @Actionable Mango
          Commuter hell, being worse case cities of the USA like Manhattan. Not just normal commuting. Interesting study on start stop here: www1.eere.energy.gov/vehiclesandfuels/avta/pdfs/mhv/idle-stop_light_duty_passenger_vehicles.pdf Including 20000 miles of fleet use on 3 different cars with start-stop where it does essentially nothing in the real world.
      danfred311
      • 4 Months Ago
      AAA is incompetent and lying. Start stop has virtually zero worth. It's a convenient lie from the nitwit douche automakers. Think a little, my sheep. Turning off the engine for a couple of seconds once in a while wont matter.
      19nomad56
      • 4 Months Ago
      I have S/S on our 2014 BMW. I've read that it's one of the more obvious system when it restarts, but you get used to it pretty quickly. Living in south OC I can't go for more than a half mile before getting to the next stoplight, so it does seem to help with my mileage. I don't run my air much, and you can somewhat control it by the amount of pressure you apply to the brake pedal (a light touch seems to keep it from kicking in).