Easy. He got in a car, put a key in the ignition and drove onto it. Duh!
Only a fool believes laws prevent crimes. Unfortunately, we have no shortage of fools.
Force prevents crimes. Like being forced into a jail cell for twenty years. Keep him in a cage and he won't be doing much drinking or driving.
Instead, we let him out, shake our finger, and admonish him that he better not let us catch him at it again. Of course, after three slaps on the wrist, what is society's credibility in issuing threats?