(There are comments in the sprite that guide you through the functions) W - Accelerate S - and back up A & D - Steering Space Bar - Brake(You can only brake when you are not pressing any of the accelerate/decelerate keys) You can drift when moving at a certain speed: hold S with A/D.
Full free car system with working physics. You can use it in any of your games, as long as you tag my name and give me credit. Have fun :)