Yeah i know, but they will need to be unwrapped too, and if i export my terrain into blender it runs VERY laggy (else i have no clue where to put the road on what height). I can also do it in sketchup, and then just model the terrain and everything, would save a lot of tris for the terrain too.
I don't understand that the geometry is there, but cannot be used for collision :s, they should fix this imho, as the feature is pretty much intirely useless without collision.