Dirt on tyres

Exactly as the title suggests, this would be a good leap graphically towards a more immersive experience.
Brown for mud, green for grass or beige for dust/sand after an off track excursion. Would look fantastic, and would enhance the whole experience.

 

They've mentioned it's coming, but not when.

 

sounds like an awesome feature to have, especially if heavy debris on the tyres could be tracked on to the asphalt etc.