Ground terrain

so basically there isnt any grass in the map because it is a map (yes i know what the terrain is right now.) made from parts with no actual terrain, so i have a simple idea, put terrain under the vegetation and add grass on the terrain below the vegetation since the grass acts like a ghost and phases through everything, my other suggestion is tire marks and drift marks on rocks, sand, asphalt, vegetation, and probably when vehicles are sliding through terrain on their roofs.