Admittedly, I have not followed the topic religiously, but as I confess to being a 'naysayer' -- not a denier, but a "sayer" with some "nays," I would like to communicate my concerns. Humans do stupid things, and certainly the roadway is no exception, but until I see some convincing proof, so far as I am aware, the human brain is far more capable of handling dynamic situations than an artificial computer.
How well can a robot driver identify what is ahead? Can it analyze the erratic driving of another car caused by another driver and determine the likelihood that it is being operated by someone too intoxicated or exhausted to drive predictably, and adjust a safety margin around that vehicle to compensate? Can it see and analyze a puddle, determine the risk of hydroplaning causing loss of control, and adjust driving for safety around it? Can it determine when an obstruction on a roadway or other conditions necessitate temporarily passing the obstruction into oncoming lanes when it is safe to do so? Can it read temporary 'detour' signs diverting traffic from, say, one side of a freeway to the other that cause modern GPS navigation systems to determine you are driving the 'wrong way' and must 'turn around?' Can it react to material falling off a truck or rock at freeway speeds? Can it realize when getting to a destination is impossible because of severe weather conditions, completely stopped traffic or other hurdles and it is time to give up and go home instead?
As I said, I have not followed autonomous drivers, so I do not know the answers to these. Is the answer to each absolutely, yes, the robot driver can handle all of these situations at least as well as a human driver?