Posting it here since the bug report site is down, and I will probably forget by the time it comes up.
In basic/docs/OJP_vehicles.txt, there are 2 lines that are conflicting:
under "TRANSITION ANIMS"
NOTE: The turnWhenStopped option needs to be set to 1 for the next two transitions to possibly occur - since otherwise you would not be able to turn on the spot at all.
under "Base game .veh parameters:"
turnWhenStopped //Doesn't do anything.
I never used the veh system, so I dont know which one is correct, although I assume that turnWhenStopped does indeed work.
At any rate, I will leave it for someone who knows more about vehicles to fix.