[s2man]

I used to think, like DifferentPointofView, that it took a long engine-off period to compensate for the energy used to restart the engine. So I only killed the engine at lights which I knew to be extremely long. But BMW has changed my mind. They are introducing automatic engine-off on their new models. The EU testing has a drive cycle which includes 12, 15-second stops on a 4.x miles course. All I can find now are articles stating this "reduces fuel consumption and emissions". But I remember reading one article which said they had an 8% reduction. Wow. That changed my thinking. I'm engine-offing a lot more now. And BMW only shuts off the engine once the car has stopped. Unlike some us who, as Daox said, shut off as we coast to the red light and save even more fuel.