Bob
As far as I can tell the answer is yes and no.
My Stroud Valleys route has emitting and absorbing Portals at both ends. I tried to lay the entire track in the direction of travel, crossovers and other junctions were AI drivers could choose the “wrong” road are protected by direction markers and I have used “drive via” in all schedules.
Despite all this, some drivers still take the shortest, rather than t he correct route and collisions or, worst still the session stops because a driver has blocked the road.
I suspect that the only answer is to use direction markers whenever a driver could make the wrong choice and also to place extra invisible signals to reduce collisions.
Chris
ps
I am planning to publish “Stroud Valleys” eventually, please could I copy the symbols and general method that you use for the trackplans for your excellent Turks Castle routes?