Pause Button

The Pause Button was an idea born to me out of necessity.  A Button on the stearing wheel or perhaps and an automatic switch inside will quickly turn off the gas at stoplights or stop signs.  The engine is still running and wasting fuel at these locations all the time... Gas just wasted as u sit there waiting at each traffic light to turn green.  Please add a button or automatic switch which I feel could revolusionize the world and save the gas we all so desperately need and pay for.