There have been many topics opened on improving vehicle pathing. My suggestion is to place paths in a similar fashion as we place train rails and belts with the main difference being these paths are not physical objects. Assign start and wait points to act as a 'station' for the vehicles.
It would also be nice to program speeds into sections of the path so that a truck doesn't try to clear a sharp turn at 70 kph when you are nearby (or have the vehicle just know that's not a good idea).
Once the path is set, just tell the vehicle what path to take and let it go on it's way! This would also make it easier for multiple vehicles to take the same paths.
