Well here, these instructions should help:
1) Name all of your cars that you want to follow the path
2) Click the Waypoint tool & click & drag to make a line. Click & drag on the last point created to continue making the path. Be sure to make a complete loop by dragging you last waypoint to the first one you made. The path should go over the road or whatever you want the cars to drive on.
3) Now with any of the waypoints selected, in the window to the right, type a name in the first
Waypoint Path Labels area. Just name is something like, "Car Path".
4) Click the following stuff:
Edit > Scripts > (select) PlyrCivilian > New Script > (tab) Actions if True > Edit. Doing this, you should've opened a lot of windows. The last one should be called,
Edit Action.
5) Now open the folders,
Unit\Move\Set a unit to follow a waypoint path. (If you're using Generals, then scroll down until you see,
[Unit] Set a unit to follow a waypoint path.) (If you choose the action right above that with,
EXACTLY in it, then the cars will go through any obstacle rather then go around it.)
6) Now with this action selected, you can choose the first car to follow the path by clicking on the link "
Unit '???'" & you can choose the waypoint path by clicking on the other link.
7) Now copy & paste the action for each car to follow the path. That's pretty intuitive so I won't go into detail about it.
http://www.cncgeneralsworld.com/generals/zerohour/worldbuilder/ Take note that it's written for just Generals, not Zero Hour, so it may be a little different.
