Why do you say that? Somebody is still going to need to be awake at the controls, at least for the first few decades of self driving tech. There's a reason pilots on planes don't go to sleep when the auto-pilot kicks on.
Good point on the pilots, though I always felt that it's unnecessary for them to stay awake (especially on cargo planes). And it looks like many do fall asleep inflight: http://uk.reuters.com/article/2013/10/08/oukoe-uk-britain-pi...
Truckers, on the other hand, need to be alert all the time, falling asleep for even a few minutes can be catastrophic.
I'm mostly hoping for fewer human drivers - two drivers/technicians should be enough to drive a whole convoy of trucks between cities/countries.
Maybe autonomous vehicles will make smaller trucks cost-effective, and big trucks will then be charged their true cost in road damage and traffic risks.
That would be a much more visible change in the traffic landscape.