var dx:int=4; //speed along x axis
var dr:int=2; //rotation speed
this.addEventListener(Event.ENTER_FRAME,moveCar);
function moveCar(e:Event): void {
	car.x=car.x+dx;
	if(car.x<=0 || car.x>stage.stageWidth-car.width)
	{ dx=dx*-1; //change direction of car
	  dr=dr*-1; //change direction of rotation
	} //hit the edge
	car.wheel1.rotation=car.wheel1.rotation+dr;
	car.wheel2.rotation=car.wheel2.rotation+dr;
} //move car