Quote Originally Posted by vinj View Post
If you are idling any longer than half a minute more or less, shut off.
That's a bit OA, IMO. Maybe if your vehicle is designed for it (Start-Stop). Otherwise, 30 seconds (+/- a few) is too short. Maybe 3-5 minutes, and only if your vehicle is parked.

You don't want to do it while in bumper-to-bumper traffic or else, you'll be shutting down and starting the engine 20-30 times per trip.