Oh yes, Super Sprint! That brings back memories! I loved to play it with three players at a friend's AtariST 30 years ago.
I even started to recreate the game on my Amiga in 1990. There is a screen shot of it in our Games Museum:
http://night.owl.de/index.php?id=54
I remember that I didn't even touch the lap-counting problem but had serious trouble with the collision detection. The cars were constantly stuck in the track borders.
I wish you good success with it! A real Amiga version would be just great!