The GTA V map is pretty detailed regarding collisions, with dirt roads and potholes being modeled, and this is communicated over force feedback with this mod. However, other details like rumble strips, brick roads, or big flat fields of grass, are perfectly flat on the collision side of things, so the road feels perfectly smooth on these materials.

The script already can read these materials - generating force feedback from this would add some nice detail and variation.

Another project already has the bulk of the noise-generating code and material definition code, but I feel I'd need to do some proper refactoring before I pull that in...