The technology exists now. The timetable (play on words intended) depends on liability and insurance issues. It will be a while before any insurance company would cover the risks inherent in driving tons of stuff around the country, a couple thousand miles a week. Cheaper to just pay a driver.
I don't know if I would trust such technology. You could have some kind of malfunction. I mean, things go wrong with cars all the time. Would you trust this technology? It could get a wrong signal or something and crash you into a wall. Lol.
I do not believe the plan is for trucks to be driven, without a human on board. In case of emergencies, a human will still be present. Just not driving.