I've written some games sketches, and I know how annoying all the suggestions from the audience can get.
Nevertheless I can't help but offer one more… when you get the car to the end of the track, it could wrap around and start going from the other end so you could have it take N laps to finish and win.
We see that in Asteroids, for example, where the space ships and stuff can be half leaving one side top or bottom and the other half entering the other side bottom or top.
In the code, it's just the modulo operator, or if the dimension is a power of two, just masking to N bits.
Now sitting on my thumbs, but I will play the versions you keep posting.
a7