Yeah, water runoff is pretty much the reason for ditches, barriers of course to try to prevent people ending up in said ditch…or bank…or river…or cliff-face-of-death… But in terms of gameplay both would, like you guys have said, balance the OP vehicles and in certain situations provide a bit of following-horde slowing. Though until the player can jump things like ditches, it’s slow us too…
So a +1 from me!
Another thing, if it’s not already in or on the list so to speak, would be “potholes”. Simply shallow (or deep hehe) holes at random points in road pavements. World’s gone to shit, right? No one out there repairing them… Long-term the frequency (and scale) of holes could ramp up, after maybe a season or two (or year) in-game…progressively making the road system very difficult to use.