To accelerate, first let go of any keys so that the brakes are off. Press up or down. To brake, if you are going forward press down, backwards, press up. This will turn the brakes on. To go again, either continue getting faster in the same direction or wait until the speed is at 0 MPH to go the opposite direction. If you don't want the car to drift when you let go of keys, press space to toggle "lock speed." This will make the speed stay the same unless you press keys to accelerate or brake.The dot on the map in the upper-left corner shows where you are. It is slightly off, sorry.
I know the dot on the map is slightly off, sorry. Looks best in full screen! I got part of the physics from http://engineeringdotnet.blogspot.com/2010/04/simple-2d-car-physics-in-games.html