So, I watched him zoom around the cul-de-sac for an hour or so, then assigned him the Family Home Evening lesson - "Road Rules You Should Never Break Especially When Your Mother Is Watching".
I know the postman wasn't amused when M went full speed right at him. Waving my arms and screeching, "BRAKE, YOU IDIOT, BRAKE!" surely didn't help community relations. But I was actually talking to the small idiot boy, not the big one.