This tutorial uses 3dsmax 6+Mental Ray, Photoshop cs [although v7 definetly has the features used] Texporter and 3dtotal Total Textures 8, the model is one I made last year, so I wont go into the modeling process.
Texturing the floor
To start texturing the floor of the scene, I used this tarmac texture from the cd as a base to work from
This render is with the texture tiled onto the object, it isn't clear where the edges are of the texture, but you can tell by the patches of bright values that it is being repeated.
In photoshop I have added a brightness/contrast adjustment layer (1), to darken and give the image less contrast, and above that in the layers you can see another adjustment layer(2), which has brightness set at -40 or so, and then I have painted on the layer mask to make the bright patches and clear tiled areas not so noticeable any more. Next I have added another layer, this one is a sandy/dirt layer ontop of the tarmac. to do this I have used a texture from the cd, the texture is a stone wall/floor but it doesnt matter because I only needed an appropriate colour/texture rather than just using one plain colour.
Then I added a layer mask and painted areas/patches of dirt on the ground, with quite a lot at the edge that meets the wall where the dirt would build up a bit. Also you can see another layer above that, using the same texture for the tracks that the car has made, these are very subtle, as the tracks are quite clear from the reflection on the floor, so they dont need to be to visable in the colour map.
This render is with reflection, you can see the tracks are much clearer after in the mask of the reflection.
I made another uvw map for the tracks, on map channel 2and matched it up to the tyres
Then using texporter I exported out the uvw's to work on. The mask is just a tile of one of the bump maps that comes on the cd that I used for the tyres