Thanks for replying, looks like I was mistaken after all. As soon as I put the curve in the road I would have been stumped again 
The good news is TFtoDistance was the ticket
can add some logic to lerp my wheel turning a bit to smooth it out, but otherwise this is behaving beautifully!
AI Vehicle now following a Curvy based road spline but still using 100% Unity wheel PhysX to move (as opposed to spline controller). All movement is AI driven with the exception of developer picking desired lane (right or left).
https://youtu.be/T7eyxjairsE
The good news is TFtoDistance was the ticket
can add some logic to lerp my wheel turning a bit to smooth it out, but otherwise this is behaving beautifully! AI Vehicle now following a Curvy based road spline but still using 100% Unity wheel PhysX to move (as opposed to spline controller). All movement is AI driven with the exception of developer picking desired lane (right or left).
https://youtu.be/T7eyxjairsE
