I'll add that Task Force Games put out their own version when they published their Autoventures series of addons for the big three popular car-combat games (king of which was CW). But generally they're a shade or two lower in quality than what SJ Games put out for their own game.
Still, they're interesting, and I seem to recall there was a counter sheet with things like road signs and animals or some such.
I hope that helps.
Edit; Game Board Geek has it listed here;
http://boardgamegeek.com/boardgameexpansion/41397/road