Everyone thought that the future is bright, but in reality, the future is something that they should fear as every people are on their own. The war has left nothing, but a trash world. The survivors joined a group for them to survive. As one of the best racers, you need to provide with the supplies that they need to survive. But going out and doing that is not easy since there are other survivors that are out to get the same supplies.
Drive your car around and look for the enemies. Shoot at them as they hold some of the precious resources that you need.