slowlane:
Human operators are absolutely crucial to the introduction of autonomous systems.The greatest barrier to widespread introduction of, in this case, trucks - is the reputational risk to the first MegaCorp to introduce it in the case of teething problems, which there will be. Teething problems for autonomous vehicles means people getting killed and maimed… people getting killed and maimed by robots is not a problem, the problem is the damage that the news of it does to MegaCorps share price.
The solution to the problem is to insert a breakaway link in the chain- a human to blame. It’s win-win - every accident let’s you make your product better and every accident increases the public clamour for fully autonomous vehicles.
The only losers are the drivers, and that’s their own fault for being born to plebs, if they’d had the foresight to be born to decent, rich folk, they wouldn’t be in this mess.
The unfortunate pilots of Air France 447 being a perfect example of humans being used as scape goats for the failings of auto pilot. 
On that note Alcock and Brown had/needed no auto pilot linked to blocked pitots on the Vimy to do the job that the Airbus 330,with all its expensive,supposedly fool proof,advanced technology,obviously couldn’t.