The whole world is in chaos and you need to escape the city or you will be eaten alive by the walking dead. Fortunately you intercepted a signal, which tells you that you need to go to a certain place, where it is heavily depended by the military. You need not to waste any time or you will be sorry. Quickly, you are able to find a truck that you can drive to go there. This is for your own survival or you may get turned into one of the undead if you can't be there at the right time.
Drive the truck as fast as you can, not because you need to get to the safety zone as fast as you can, but the fact that you will get higher money if you got momentum at your side. Basically, you will get more money based on the distance, but the idea here is to drive the truck against the zombies to get more money. You will need to drive the truck and ram the zombies as fast as you can to get more money. You can use the money to upgrade your truck later in the game or buy a new truck.