I'm a truck driver. My analogy, zooming out a bit, is that the entire road system, at least the National Network, is a system of interconnecting and overlapping conveyor belts.
True - still a lot better than painstakingly offloading a ship's cargo onto trains and trucks and vice versa, one crate at a time. All of civilization runs a good deal faster and better because of shipping containers
I'm a truck driver. My analogy, zooming out a bit, is that the entire road system, at least the National Network, is a system of interconnecting and overlapping conveyor belts.
The trailers are trays on the belt.
https://en.m.wikipedia.org/wiki/National_Network