It depends on how good their marketing is. Trucks will initially probably still need a human in the cab. Truckers often drive in pairs so that the rig can be rolling for 20-22 hours per day. The way you get drivers to embrace the technology is by lobbying for laws that would allow a single driver to be at the wheel for, say, 14-16 hours at a time.

That's enough for a pair of drivers to keep the truck on the road continuously, and maybe almost enough to make it worthwhile to have just a single driver (so the cab owner doesn't have to split his profits with anyone). After gradually raising hours over the course of a few years, you can declare drivers optional. Owner-operators would still ride in the cab so they could handle pickup and delivery of trailers, but fleet owners might just hire drivers on the spot for things like that.

Edit: My (mis)understanding of trucking hours of service was based on a conversation with a truck drive a few months ago. Apparently, you can drive 14 hours continuously after taking 10 hours off. However, I think the point still stands that truck drivers will be less resistant to the introduction of robotic trucks if they perceive the change as a (at least short-term) benefit to them by increasing allowable driving time.