Truck drivers. There sure are a lot of them in the US.
Not just truck drivers - any job that involves moving someone or something from point A to point B with a human behind the wheel is a target for elimination. For the most part, a job in the transportation industry pays a livable wage. If transportation jobs are rendered obsolete by autonomous vehicles, we're talking a mind-mindbogglingly huge number of workers who will have to retrain for another career, or fight for the remaining low-wage jobs that are available to unskilled workers.
As much as politicians love scaring the American public with the specter of terrorism, it's the dropping value of an hour of unskilled human labor which should really be sending chills down peoples' spines. The point some members of the liberal camp fail to see is "minimum wage", is a misnomer. It's a minimum cost of labor, and raising it is akin to price fixing a commodity that is in obvious oversupply. Some municipalities have already done just that. Allow that to sink in: We have so many unskilled laborers willing to work for unlivable wages, that we've actually had to pass laws mandating they're paid more than the free market can bear.
Star Trek and and the Spaceship Earth attraction at EPCOT told us automation would provide us with a life of leisure, while we're free to pursue our dreams. You'd spend the day composing music, designing surfboards, painting, etc., while Mr. Roboto goes to work for you. In the real world though, Mr. Roboto works for the big corporations, and they see no need to employ *you*.