Kristin, a contributor to Celsias.com has done a bit of research online, as well as some real-world testing to come up with what she is calling the "Homemade Hybrid" ten second rule. The idea is to shut your car off and restart it manually whenever you stop for a stop light where you expect to be sitting for more than ten seconds. I have heard of the old rule that it takes three minutes of stopping the engine to save the gas it takes to restart the car, and have thought that seemed like a long time. Kristin correctly points out that the constant starting and stopping may wear out the starter a bit faster, but that difference would most likely be made up way before it came time to replace the starter. In her own testing, Kristin found that she saved a whole gallon of gas, or about 30 miles of driving extra per tank of gas by implementing this technique. Anybody else out there care to give it a try?
Edit: Changed the word "less" to "more" - thanks Howard!