In 3 years all truck drivers will be out of work? We don't even have fully autonomous trucking released now (beginning the early adopter part of the technology adopter cycle)... so that seems a bit far fetched.
The road is not predictable. A deer running across, a car cutting you off, rain, snow, a tire blow out, any number of random events can happen. It just occurs less often on a freeway than the city. You still have the solve the same problems, however, if you don't want a human in the car.