Right after you destroy the horns blocking the final zones (forget the zone name, at work, I'm lazy). After you cross the bridge you're hit with a dead end on one side, and the correct path on the other. The mini-map has 3 grey squares(I think they're lamp posts). Go the opposite direction of those grey dots for the proper path. I haven't tested this enough to make sure it's 100% correct, but so far after 20+ runs, it's been the correct direction.
Course, this only saves you <3 seconds but speed runners want those 3 seconds I guess. :)
I know someone on the racing discord created a bunch of them a while back. I still remember a few and use them here and there while levelling. Makes the campaign so much more fun when you can just blast through a zone in 10 seconds with a tricky read.
Has anyone attempted to gather them all in one place? I must have seen a good 40-50 of them over the years.