http://www.alternativefuelstips.com

A vehicle left idling for a long period of time uses up gallons of gasoline without covering any miles. Obviously, this translates into fuel wastage. Drivers who anticipate temporarily stopping in an area for more than a minute can save gas by turning off the engine and restarting it as needed. Of course, this is not recommended at red lights, but adopting this practice in heavy traffic can save more gas than drivers expect.
http://www.alternativefuelstips.com