How to modify road drivability for AI.

I've been having trouble with modifying the decalRoad drivability for AI, i saw by default for decals that used the decalRoad tool that AI should not path on, the drivability was set to -1. However, when i tried this it did not work, and the AI still drove on them. I saved the level and reloaded it, and they still drove on the roads. I then tried deleting said roads, and they still chose to drive on them. I now have no idea how to keep AI from going certain places...
This is all on WCUSA by the way, in the case that changes anything.
Also sometimes when i saved and reloaded the map the values would revert to 1, but even when they didnt the AI could still use the roads.
--- Post updated ---
Obviously this must be possible... Is it not?

 

Another update. Apparently it is not possible no? how do people make new maps with AI then?

 

I think a setting of -1 would ignore drivability completely, but I am not the programmer. Try a setting of 0 maybe?

 

I tried both, neither worked or sometimes didnt save. OP applies.

 

Does nobody have any idea how AI works?

 

The road drivabilty thingy works fine for me. Dumb question, but did you save the level, then exite the level and then tried again?

 

I believe i tried that too, ill do it again later. Did you try it on the same map? maybe the devs just made official maps impossible to save or something.

 

set the decal road driveability 1