http://www.lfsforum.net/showthread.php?t=26334&page=2 seems rather similar, also there are red lights as well as the yellow ones. I don't know if any circuit championship uses them often, I'm not sure if F1 uses them at the brickyard ...
These should be at the end of the pit lane too, with blu lights for cars approaching and red and green light respectively before and during the session.
I meant the lights at the side of the track that are yellow, blue and red. F1 has them in the car cockpits, and they are designed for drivers incapable of seeing flags anyway.
Starting lights are a different issue. I'd like to see ALL LFS tracks have two options - 5 reds on, go when off like F1, and then the one red only BTCC type system. Maybe an /abortstart command if needed, or maybe autoabort the start if someone stalls or there are circumstances that IRL would abort the start.