The "trucking industry" is unlikely to be an agent of change. They are entrenched incumbents who will fight, lobby, and bribe to stop automation.
Again, why would they do that? The only members of the "trucking industry" who stand to lose if trucks go automated are truckers themselves, but they can't possibly out-lobby trucking companies.
Progress is more likely to be driven by customers such as WalMart, or entirely new transport companies.
No. Wal-Mart will just contract with whoever can moves the trucks most cheaply. But they're not going to do the leg-work themselves. They'll just contract whoever has the self-driving trucks, after they do the lobbying.
Wal-Mart doesn't give a shit how cheap trucking is, only that they get it at the lowest possible cost, because they don't care what their prices are, only that they are lower than the competition.