Ever notice that some people seem to turn off their car at a stoplight, then start it again when it's time to move?
I thought it was a manual thing, like a superstition. I also suspected it was a waste of gas; that the car wasted more gas starting up versus just idling for a short time.
Turns out I was wrong. Not only can it save around 7-26% in gas, it's an actual feature built into modern cars.