How do they learn?
Each car has a tiny neural network. It sees five distance sensors and its own speed, and decides steering and throttle 60 times a second. In generation 1 the weights are random, so the cars know nothing.
After every generation the run that got furthest (or finished fastest) becomes the champion. The next cars are mutated copies of the champion, some with tiny tweaks and some with big ones. Keep what works, discard what crashes, repeat.
The gold ghost is the fastest lap ever driven. The white ghost is the best attempt so far, and the purple ghost is the best car from the previous generation.