Darkwind: War on Wheels

From the game's website:

Darkwind is a free turn based tactical car combat game in the style of car wars online and Mad Max online. A free car wars computer game or car combat MMO. A turn based online strategy role playing game or war game. Similar games include Jagged Alliance and the Car Wars boardgame.

Battle for survival and supremacy in the gritty post-apocalyptic world of vehicular combat where strategy and tactics determine winners and losers. Manage your gang, train your characters, design your own cars and scavenge for parts. Make your fortune in racing, deathracing and arena combat leagues, or venture into the wilderness and engage in tense multiplayer battles with pirates, traders and other players. Trade for parts, cars and weapons in the dynamic economy of a world where your characters will age, sustain permanent injuries, and die. The detailed weapon stats, and the detailed combat system with critical hits, injuries and healing, psychology and leadership ensure a strategic challenge like few other games.