Recently I read about a stop-start feature in automobiles. It is designed to reduce pollution by stopping the engine when the car is stopped, and starting the engine automatically when the gas pedal is pressed.

A friend and I were discussing. Our gut reaction is to doubt this saves much energy. Where is the correct site to ask about this? Specifically, we are interested in the energy saved (running the engine vs. restart). I know this area could be quite broad, so I want to narrow my question a bit.