Self-driving cars are currently proving safer than manually-piloted ones. There isn’t a good reason to segregate traffic like this.
> what would stop a few cars passage in front of the truck and helping themselves to the cargo
Why do you think a trucker would risk life or even their truck in a highway robbery?
That's an armed robbery whereas stealing from a robo-truck is more like breaking and entering. Robberies require the willingness and ability to commit violence. Having a human witness present means more risk of things going wrong, even if they don't intervene. I think all these factors prevent a lot of potential crimes.
If you ask truckers they'll probably say something about blue lights and asking to see license and registration.
As to why that doesn't happen now? If you try to rob a piloted truck in the middle of nowhere, whether or not you plan on hurting the guy, he's going to fear for his life (why would he trust your good intentions if you're robbing him?) -- and if he fears for his life, there's a good chance he pulls his gun on you. That means you need to come prepared to commit violence and risk him doing the same
You simply iterate on the problem and see if the percentage goes down.
Not to mention you're proposing somehow making off with the contents of a semi truck in a covert way, even though it's so much stuff if takes a semi-truck to move.
“HVL Do Not Stop List” (High Value Load)
Thus I learned some truck stops in Texas, California, and elsewhere are too dangerous for “L Brands” (Bath & Body Works?) truckers to patronize. Unfortunate the human factor is not a sufficient deterrent, but agree—
A candy store is a less attractive theft target than a vending machine.
As a general thing, no, we've not really had study confirming that. The stats we have are biased by the feature preselecting good drivers, good weather conditions, known road segments, and other things.
Unfettered access to 5 lanes of freeway.