A truck must be proven to last long on the long road. It also need to be able to pass those high mountains, meaning that it should have a powerful engine capable of that. The body must be durable since it would carry lots of things. If is not durable then no matter how good a driver is, he can't deliver the item unharmed to its destination. That is why; truck companies are making some testing. They want to be sure that there truck can be useful for a long time and that it would deliver as promised on their promotion. The power of the engine and its durability are the top keys in selling a truck so the truck companies are really making sure that it would pass their standards.
Drive your truck as pass as you can and get to the finish line in the least time possible. Nothing will happen to your truck if you can't beat the time, but the bonus surely dwindle down each passing time. As always, advancing in the game means that there will be more obstacles to make things exciting. There are three trucks to choose from at the start of the game, but you can't change your truck once it started, so you need to carefully select your truck.