Stop-Start Engines Save Gas

A growing number of cars are coming equipped with a “stop-start” system that automatically depowers the engine while sitting at a stop sign or at idle to save fuel. It starts the engine up again in less than a second, usually when the driver lifts his or her foot off the brake or clutch pedal. Such systems are more frequently used in Europe, though they’ve long been included in fuel-frugal hybrid cars and crossovers sold here. Unfortunately, their effect becomes lost in the U.S. insofar as a model’s official fuel economy ratings in the U.S. are concerned. That’s because the test cycle the Environmental Protection Agency uses to evaluate cars considers less time spent at idle in its urban-driving evaluation as does the system used in Europe. However, a recent study conducted by the AAA in Orlando Fla. concluded that such systems indeed improve a vehicle’s fuel economy in around-town driving by five to seven percent, with an equivalent reduction in carbon dioxide emissions. “Up to seven percent improved fuel economy can mean an average $179 annual fuel savings for consumers,” says AAA spokesperson Greg Brannon.