I believe such automation will be very possible within our lifetimes. Especially in my line of work in feeders. I am just crossing my fingers that this kind of automation won't be my replacement until I am much closer to my target retirement date of 2041. Automating package car operations would be a lot tricker process given all the variables, but rest assured it is being looked into.
A lot of industries are looking to robots and automation to replace human workforces, and I have to ask the question what kind of future will we have when robots are doing everything that humans used to perform for work and compensation? Will we all be sitting at home earning some form of government welfare to make up for the fact that the jobs no longer exist? UPS wouldn't need as many trucks on the road I guess if this were to become a reality because fewer people would have the means to order much anyway. The capitalist in me wants me to believe that this would free up people to learn other careers and skills, but my gut feeling is those new positions will be fewer in number than the number of people replaced driving trucks, working in factories, and doing other tasks. I am not so sure even education level will matter as automated options are being explored to replace people in high level jobs that require a decade or more of schooling like doctors and lawyers. Where we will end up is anybody's guess, but I hope to have myself set by the time the driverless tractor's rubber is meeting the road.