You can use some trigonometric math to test the angle of the car in relation to the next waypoint on the track.
The ACOSd at the end of this blueprint logic outputs the angle of “Self” in relation to another Actor. If it’s greater than 90* or less than -90*, you know the actor is facing the wrong way. I would set this up at an timing interval instead of using Tick, but it’s in this to output the Current Relative Angle.
Angular Formula: VectorA Dot VectorB = VectorA length × VectorB length × cos(θ)
(see Dot Product for detailed visuals of what we the above is attempting to accomplish).