I think the way transport of goods is handled on highways provides possibilities for autonomously piloted cargo vehicles to start hauling loads back and forth in the next two decades or maybe even less. The technology is here already, but people don't have complete confidence in it and rightfully so. Remember the accident with the Volvo ceo who got ran over by their own car?

It's possible to have unmanned transport delivery vehicles on the highways even with the current tech. However it will be necessary for them to move in separate lanes and those lanes will have to be secured so as to decrease the chances for endangering the lives of regular people in the traffic.