I wonder what % of truck driving is highway driving? If you are covering the trucks in cameras and you have the control software there already it seems pretty easy(relatively at least) to have someone take over via remote for the last mile.

AI sensors combined with some sort of 360 view VR with drivers for the last mile with full AI on highways/freeways would allow for progressive roll out of self driving technology. A lot of video to push down the wire though but probably manageable with modern codecs.