Very, very cool idea. I like the idea of not having much read ahead for what's coming next, almost like a rally game where you're going off of co-driver notes (though I guess that's read ahead?) The sharp turns were absolutely evil.
This has unlocked an ancient memory - I remember playing a flash game, probably around 2002-2004 that was similar. I think it might have been hosted by LEGO and technics themed: you'd choose a car and pick from some stats and then drive a course to a checkpoint where you'd choose the next leg of your trip. I think the tracks were somewhat procedural.