Cars travel at h igh speeds creating wind. (Score 1)

Why couldn't you combine the two, so when the car was parked sun would convert the hydrogen and when the car was moving wind power would convert the hydrogen? -- Or better yet have a large water tank with a small fuel tank and they are used alternately depending upon wind speed and direction. One could even put a device that is similar to a weather vane on the roof of the car so the strongest source of wind is always turning the turbine. I don't understand any of the science of it. so it is probably a stupid idea, but one that in my mind begs to be asked.