It's true. He's three years old. If you can't control a three year old then you fail at life. I work at a daycare in a room full of ten screaming three year olds but I can still get them to pay attention. Next time, take the cars away from him and make him sit in the corner. Every time he gets up, put him back down. As long as you're more patient than he is then eventually he'll get the picture and he'll back down. Otherwise, I suggest duct tape, or put benadryl in his milk. He'll be out like a light.