I'm surprised the trucking industry isn't spending their political capital pushing for fully automated, driverless trucking to be allowed sooner rather than later. I mean, I know they've already really screwed truckers out of what used to be pretty lucrative income contracts, possibly delaying the push for driverless trucks by a few years, but the film "Logan," set in 2029, has several scenes featuring fully automated trucks, and I think it's entirely plausible - maybe even probable - that such things will exist by then. In that film it looked like the trucks were basically wheels, motors, batteries, and a computer that took a full-sized container and sped it off down the road towards its destination. Something like that sounds a lot more efficient than changing the size of trucks would be, especially eliminating cost of a human driver.
EDIT: Jalopnik has an interesting article about
the future vehicles in Logan, not only the autonomous trucks (the section about them is near the bottom).