Original author just wanted me to pass along that he hates you...because those textures far surpass anything he's capable of...
Track was a sore spot for him as it was originally intended to have falling snow and icy tail-happy setups. He did some experimentation and got some white dots to fall but fell short of making them float realistically.
Further, back then there wasn't much love for road courses so he kinda did a rush job on the place. Plus he just couldn't make a very realistic snow-covered texture for the roads...so he gave in and just released it w/ plowed roads.