I noticed this during the racing when my car was tipped up:
Thats because there is a large gap between the ai nodes when you drive down the road and they only continue at the jump.
This should fix it (placed a few nodes in between) -> http://www.mediafire.com/?xo8c28vcy299q8y
You are still being teleported after the jump when you reposition yourself right before the jump because the ai nodes in that section are marked as Jump Wall.
But you can't really get any advantage out of it anymore so I figured I leave these nodes untouched
edit: forgot to fix the reverse nodes, the problem there is the exact opposite situation. If you reposition yourself in the middle of the roof you get repositioned at the beginning of that section (where the jump is) so its definitely a disadvantage for you.
This can be fixed by placing a couple of nodes in the empty gap just like I did above but I'm too lazy to do that now