It seems that at the moment there are just intangible, small vegetation, and then concrete bushes. It would not be realistic to make the bushes intangible too, but maybe make them like say, a "bubble of water", give them a simple geometry hitbox so if you go trough them it might slow you down (I think the word is "viscous"?), maybe add a small "leaves flying around" particle effect and sound, and make them clog your radiator a little (so if you ram through a bunch of bushes, you end up with a clogged, useless radiator but not a totalleld 10 ton truck) I don't know if that would be too hard on the optimization side... Any ideas?
That's great! Are you going to take the "just visual" approach, or will there be any punishmnent to the car? I bet that's going to make taking shortcuts or cutting corners more tempting, but also risky