The Tabletop Terrain blog has a useful article on using vinyl/linoleum tiles to make roads appropriate for a combat zone or post-apocalypse setting.
roads
Making Roads From Cork Tiles
The Wargames Table has a quick tutorial on making roads from cork tiles.
Making Roads For 15mm Wargames
Here’s a tutorial for making roads for your 15mm wargames.
The principal ingredient in these roads is vinyl composite flooring.
Making Roads From Roof Shingles
Roof shingle material turns out to be perfect for making roads in a variety of scales. This tutorial from Architects of War tells you how.