Ever notice how much skill is involved making those tight turns?
The funny thing is, so much of that skill is necessarily because a mere human has very limited awareness of the space and obstacles around such a large vehicle. It requires a lot of intuition and practice for a human to be able to do that reliably... but not so much for a vehicle with a couple of LIDAR units and stereo cameras that knows exactly where everything around it is to within a few centimeters and can use a pathfinding algorithm to figure out the most efficient way to maneuver into a given position.
Sometimes the trucks have to move over into the left lane just to get turned to the right. Will a computer-controlled rig do that?
Yes, why wouldn't they be able to? Lane detection and predicting how wide an arc you need to turn are easy.
And sometimes even the most skilled driver gets his rig into a spot where he has to back up several times and try again and again. Can a computer even come close to that kind of skill?
Yes, and because they can calculate the exact angle they need to turn at and how far they need to move, they'll be able to do it much more efficiently than a skilled human driver.
Can a computer back a truck into the dock behind your local supermarket when space is barely available to maneuver? Even some truck drivers wince at doing that.
Yep. Again, the reason it's hard for a human driver is only because they don't have persistent knowledge of the world around their vehicle and the ability to predict exactly how the vehicle will respond to any given input.
I get the notion that whoever comes up with these hair-brained ideas hasn't.
I get the notion that the people who spend five minutes thinking about things they think will be hard for autonomous vehicles to do and then post it on Slashdot don't realize that there are teams of people who have been working on these problems for well over a decade now.
The hard things for vehicles to deal with are poor terrain (like an old dirt road overgrown with tall grass, or a road completely covered in snow) and unpredictable human drivers. The logistics of "how do I maneuver efficiently through a tight space" are the easy part. Maneuvering through a city is tough, but it's because of all of the human drivers that zip unsafely back and forth between lanes without signaling, don't leave enough space for other vehicles, blow through stop lights, and so on.
Still, keep in mind that the vast majority of time spent driving a freight truck is on the interstate. Even if it's a while before trucks can operate autonomously within city limits, it'll be easy to have an unmanned truck drive between cities and then just send a driver out to get in the truck at the city limits and drive it the rest of the way. That will still be enough to shred the truck driving industry.