Everyone knows that if you're going to be idling your car for a while, you should turn off the engine to save gas. But how long or short, I've always wondered, is that "while?" I'd heard 3 minutes, I'd heard 30 seconds, but most often I'd heard "leave your engine on. You don't want to wear out the starter."
I decided to do some research. It was harder to find an answer online than I thought. Click & Clack only say "If you're stationary for more than a couple of minutes, shut it off, and save gas." The EPA website is vague, suggesting merely to "turn off your engine if you anticipate a lengthy wait." (http://www.epa.gov/otaq/consumer/17-tips.htm) Even the U.S. Department of Energy, Energy Efficiency and Renewable Energy site says "Idling gets 0 miles per gallon. Cars with larger engines typically waste more gas at idle than do cars with smaller engines." And I say, Duh!
At last, the Canadian Office of Energy Efficiency (http://oee.nrcan.gc.ca/english/index.cfm), provided me with a rule of thumb, and the answer surprised me. If you're going to be idling for more than TEN SECONDS, you'll save gas by shutting off your engine. Ten seconds?! Stoplights take six times that long, at least!
As a matter of fact, in Basel, Switzerland, it is a law that everyone has to turn off their engines at stoplights. This city was once the dirtiest in Europe (the Rhine river caught fire), and now it's the cleanest. Is anyone paying attention, here?
No, in America we're still thinking in the Stone Age. Or at least the carburetor age, when it really did stress a car out to be turned on. All cars are now made with fuel injection, and starting a warm engine is nothing. "Doesn't it wear out your starter?" A guy asked, who was listening to the conversation I was having with a Saturn mechanic. The answer is maybe a little, but if you have to replace your starter six months earlier, so what? The savings you get in the years until that happens are worth it.
What savings? I tried it myself to find out, and was amazed, when I went to fill up on gas, to see that I had gotten 30 more miles on that tank than usual. Thirty more miles -- that's more than one gallon of gas. If I could save a gallon of gas every time I filled up, I'd have $75 extra dollars at the end of the year. And I drive a pretty fuel-efficient vehicle already. A 10% savings on every tank of gas would really add up if I drove an SUV.
So spread the word. Try it yourself. And think about stopping the war, saving the environment, and breathing better while you're at it. If we all used the 10-second rule, we'd be saving more than gas.