I worked on this, three month time, project as a tech artist/texture artist. Our customer gave us this open source Monza racetrack model in order to replace the main textures (asphalt, grass, tarmac, sand). My goal was to carry this track to the next gen visuals of Unity 5 and PBR rendering. I focused on procedural materials in Substance Designer, graphic and collision mesh in Maya and some photoshop texture integration.
After that I worked on lighting set-up, unity terrain, and postprocess FX.