Not only can traffic lights cripple your morning commute, they could also be hurting your wallet. The National Transportation Operations Coalition reports that out-of-sync traffic lights cost the average household five trips to the gas pump every year. "There are literally billions of gallons of gasoline nationally that could be saved if this country were to pay better attention to its traffic signal timing," says University of Maryland professor Peter Tarnoff. According to the coalition, better control of the nation's traffic signals would reduce congestion by as much as 10 percent, cut air pollution by a fifth and prevent accidents at intersections.

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