Is there a possibility to set something, so your car can only drive on the way? So you don't need to set actors next to the way with a collision rule.
There are multiple ways to do this but the solution depends on the way you move the actor.
The attached file has two scenes. The first one uses the Move behavior (and your left and right keys on the keyboard), the second one uses the Constrain behavior (and mouse movement).
Thanks for help