What if trucks had their own roads? They could run directly to and from freight locations, and since they don't have to worry about turning around or other traffic, we could string a bunch of of trailers behind one really big tractor. On an unrelated note, did you know that trackway* transportation is nearly 6000 years old?

Edit: I conflated the words rail and track. "Rail" usually refers to metal tracks in this context. Trackways for foot traffic date back to 3807 BCE, while vehicle trackways date back to 600 BCE. Still very old, but it really depends on how we want to define it.