We drove in one of the trucks at the very start of the game. They are always parked around the knot cities but the wheels light up red and I can’t get into them. Is there a way to unlock these trucks so that they can be driven?
Yes, it is possible to drive the trucks. As you get further into the game you will start to notiec some of them parked around the place, left behind by other players. The shared garage will often have trucks in them too. I am guessing you need to get 5 stars reputation with a knot city in order to be able to take the trucks from the main yard.