Are you using a patched version? In the patched version the haze works like it should. It isn't visible all over the track, but on specific sections. You should be able to see it.
Larry
AMD 3000+,Epox EP-8RDA,Ram 1536mb 333 DDr, Rad 9800 pro omega 2.4.96, dx9b, Audigy, MOMO FF,winxp