When it comes to self-driving technology, some of the biggest and earliest gains could come in the biggest vehicles. More than a few companies are working to deliver 18-wheelers that eliminate the human behind the wheel, drastically reduce their workload, or relocate them to a driving simulator in a cubicle.

That's great for trucking companies eager to cut costs, and for safety as well: Crashes involving trucks kill about 4,000 people on US roads every year. Artificial intelligence systems excel at the kind of monotonous concentration where humans so often fail. They don’t get bored, complain about roadside food options, or demand pay raises. They see farther and react faster, so it makes sense to bake computer control into big-rigs, to make them safer and more efficient.

The tech is not so great, however, the people who work one of the most common jobs in the country, one that provides a steady middle class income. “It’s a hard life,” says Allie Knight, who drives a big rig and vlogs about life on the road. “You have to maintain a large vehicle on the road for three to four weeks at a time. It’s not just a job, it’s a lifestyle.”

Despite high profile demos in which autonomous trucks delivered beer (Otto) and rolled over the Hoover Dam (Daimler), Knight and her fellow 2.8 million truck drivers aren't out of work quite yet.

“It’s relatively easy to stage a demonstration that looks impressive but to get to the point where a system is ready for public use is vastly more complicated and challenging,” says Steve Shladover, who studies autonomous driving at UC Berkeley. Knight makes the same point, as she crawls under her semi to whack at iced up brakes with a hammer.

Challenging doesn't mean impossible, but even as this shift comes, it may not destroy trucking as a human endeavor. Startups Starsky Robotics is developing a driving system that handles the truck on the highway, but relies on a remote human to navigate the much trickier surface streets. The era of the human driver goes on—but life on the road looks a lot different.