The following is a step by step guide to building a road for your DBA battles. Before we get started here is a list of what is required to take on this project:
Using the hobby knife and the 0.5mm thick styrene, cut some straightish strips about 40mm wide.
Paint the road brown... I did a couple of coats to cover up the white, but feel free to leave the white showing through in some places to give the illusion of texture.
Using a lighter brown (much lighter), successively highlight ruts and lines into the road to give it the illusion of texture. To smooth out the highlights, paint it over with a very watered down brown. At this scale, I didn't bother with actually adding texture because I didn't feel it was needed. Also, leaving off the texture makes it faster, easier, cheaper, and potentially more durrable than it would otherwise be.
Following the contours of your painting, put some glue along the edges of the road and put on there your favourite grass or sand flock. I like the static grass.
Once it dries, you're done! Simple as that!