If this were to come to pass, it would be a massive hit to the middle class. Truckers make up a HUGE part of the American middle class work force.
Also consider the economic impact to all of the gas stations and rest stops created primarily to service them, a huge amount of infrastructure exists to service truckers. That said, many could convert for autonomous service needs? I expect it to be a net loss for them also. RIP Loves?
And from a technical point of view, it's a lesser challenge than generalized self-driving because point A and B are already known for each route, so more of the route could be "hardcoded" (not actually hardcoded but I think you get the concept).
That said, I can't predict the timeline of when this would be feasible, but when it happens I expect it will cause a lot of anger from truckers.
Anyway, the jist of my comment, this will route a substantial amount of middle class wages from the truckers to the truck owners, increasing inequality even further.
This is the biggest catalyst to sway the public toward a UBI than anything else I can imagine.