>For example: following verbal or gestured instructions from a police officer or construction worker. We don't even have _theories_ on how to build intelligence like that, yet.

The main problem with having humans take over control in situations the car can't deal with is if the switch needs to happen at speed. If you're crawling along near some accident getting input from someone directing traffic, it doesn't seem like it should be a problem to get the human's input with voice commands, or touch on a dash-mounted tablet, as to what to do next.