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Automakers drive ahead with start-stop systems

Automakers hope start-stop systems will satisfy consumers’ love for large, high-powered cars while also meeting the Environmental Protection Agency’s fuel economy standards mandating car fleets average 54.5 mpg by 2025. This technology has gained popularity in the past few years as automakers inch toward the 2025 fuel economy deadline. In fact, some experts predict start-stop systems will be in all new cars within a decade. Here are a few things you should consider about start-stops and how they may impact your driving experience.

Driver of a car with a start-stop system at a red light

How start-stop technology works

Start-stops represent an engineering approach for tackling fuel economy challenges. The primary goal of start-stop systems is to save fuel. Reports from Edmunds.com estimate three to 10 percent fuel savings depending on various factors. Longer stops result in more fuel savings. So if a car usually gets 20 mpg, a start-stop system would increase fuel efficiency to a maximum of about 22 mpg.

You may have read or even experienced how start-stop systems seem to automatically downshift when the driver presses the brake and brings the car to a halt, such as at a stoplight or in heavy traffic. When a car equipped with start-stop technology comes to a complete stop, the start-stop system cuts spark and fuel to the engine, which saves fuel that is otherwise used to power an idling, non-moving car. Engineers have worked to ensure the start-stop engine almost instantly restarts when the driver disengages the brake and presses on the accelerator.

The effect on driving

Some drivers dislike start-stop systems, saying they are noisy and make the cars seem to tremble or stall. Indeed, some news reports estimate that about 40 percent of drivers at least temporarily disable the start-stop technology in their cars. According to auto enthusiasts, drivers of high-end luxury cars are less likely to find issues with the technology, noting that those cars have noise-cancelling insulation and more refined start-stop systems.

Adding start-stop to your ride

Auto experts recommend against retrofitting a car with a start-stop system. The car’s starter, battery, computer system and more would need to be modified to accommodate start-stop technology. Not only would those efforts prove costly, but chances are also high that start-stop may still impact the car’s computer and other electrical systems.

Vehicles with start-stop systems

Start-stop systems aren’t new. In 1983, Volkswagen introduced its first production vehicle with start-stop in a European model, but the technology has taken more than 20 years to gain popularity. Now you can find start-stop systems on a variety of U.S.-built cars, including sedans (Chevrolet Impala, Chrysler 200), trucks (Dodge Ram 1500, Ford F-150) and luxury vehicles (Cadillac CTS). And more and more U.S.-built models may add them as fuel economy standards change. Already becoming the norm in Europe, between 40 percent and 60 percent of European cars currently feature start-stop systems. So it’s important to know what start-stop technology is all about, especially since it might play an important role in your next car purchase.


Nancy Dunham is based in Washington, D.C. and writes for Automotive News, National Automobile Dealers Association and other major publishers.

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