The 10-second rule

I see it all the time - drivers parked in grocery store parking lots with the engine idling, while talking on a cell phone. Or a driver waiting to pick someone up, engine idling. Ever wondered how long does a modern car have to idle before it makes more sense to turn it off? The surprising answer: only 10 seconds! Here is an interesting article describing "The 10-second rule."

http://www.slate.com/id/2192187/