Plus, with buses, they can make smaller buses that have more routes and can also respond to demand to better stick to schedules. (If 13 people "check in" at Bus Stop B but no one at Bus Stop A, then the bus can take a shortcut that avoids A and goes to B sooner, to better handle the larger amount of people waiting to get on.)
1) convince the unions to let us
Even if the tech is viewed as very mature by every automotive professional, Average Joe will still view it with heavy skepticism. Having a human who could take control in the event of a bad situation will alleviate a lot of concern, regardless if the human could not realistically do anything useful even with very early warnings and a sharp eye. Public trust will probably grow at the same rate as bus drivers quit/retire, which brings us to the union solution: Attrition. Everyone keeps their job and rate but does less. Make them drive the bus in and out of the storage facility to keep their driving skills up and give them busy-work. No new blood, raises are probably capped off, but the drivers can keep working until they quit/retire or a specific amount of time (like 5-10 years) has passed.
While I've not dealt with a union directly (only felt some indirect effects, like not being able to move my own desk), I think that would be acceptable. As an added (evil) bonus, the driver can be a scapegoat if a bad accident occurs.
(I wonder if buggy whip makers had a union that had to deal with this...)