Shouldn’t be too hard, I’ve built an ai racing system like this before, but for 2d instead of 3D. I’m not sure how their AI racers work but the ways they usually work are somewhat standardized.

Since you have a set of premade pieces you would make a set of AI instructions for each piece and then connecting nodes on each part of the piece that can ‘connect’ to each other, and then collect those instructions into a single set to be ran by the AI

They probably don’t have a system that will let them place ai instructions in chunks and connection nodes like this since that part isn’t necessary on the premade tracks and couldn’t rationalize taking the time to set it up.

I guess the game is dead now but I’m not 100% sure. It wouldn’t be that hard of an update to make though unless they have some really weird AI. Could also just make a new simple ai that pathfinds it’s own way but the loading may suck