Good idea. This IS actually a waypoint system already. No matter how you look at it you would have to store points to represent the center of the track.
An important thing to note is that while the median may give you a clear route around the track it will not necessarily be the quickest racing line so your AI may be easily beaten by cutting corners etc...
For racing AI I generally precompute the best line / approach speed for each waypoint based on the length of the previous straight / the sharpness of the current turn and the vehicles max yaw rate. Once you have that you can adjust each vehicle so that it picks a point which is offset from this waypoint by a random amount and with a target speed slightly higher or lower than the baseline speed. Factor in different braking / acceleration etc.. an overtaking routine and you have some very smart / realistic vehicles which will never take exactly the same line around each corner and at their best will be very difficult to beat.
Good luck with it BTW!
Stevie
An important thing to note is that while the median may give you a clear route around the track it will not necessarily be the quickest racing line so your AI may be easily beaten by cutting corners etc...
For racing AI I generally precompute the best line / approach speed for each waypoint based on the length of the previous straight / the sharpness of the current turn and the vehicles max yaw rate. Once you have that you can adjust each vehicle so that it picks a point which is offset from this waypoint by a random amount and with a target speed slightly higher or lower than the baseline speed. Factor in different braking / acceleration etc.. an overtaking routine and you have some very smart / realistic vehicles which will never take exactly the same line around each corner and at their best will be very difficult to beat.
Good luck with it BTW!
Stevie