When we are driving places we see so many trucks. Sometimes I can see what is on the trucks, but usually they just look like a great big box with a cab in the front. Our RV has a cab where my Dad drives and I sit next to him. But the truck cabs look much bigger, and I keep wondering what is inside those trucks and why there are so many of them. Can anyone help me to understand more about trucks and why there are so many on the roads in America?
Maybe these photos will help you to help me: