Liability: who is liable when the car kills a pedestrian?
Driver engagement: How do you safely transition from automatic control to manual control.
Maintenance: Will the manufacturer be obligated to provide software updates for the life of the vehicle? Even if that vehicle is 20 years old? Even if newer software is 10x less likely to kill a pedestrian?
Cost: Are the costs one-time or will there be a maintenance fee?
Licensing: Does the manufacture have the right to disable functionality after the purchase? Do they have a right to your data? Can they sell that to your insurer?
Regulation: Who certifies systems? How do they test them? When is a system "good enough?"
All of these things sound trivial compared to the technical challenges but it's these kinds of non-technical challenges that killed the small-airplane market in the US and are still unresolved 65 years later.
Nvidia mentioned identifying humans, dogs, parked cars, trucks, street signs, street lights, etc better than a human.
On their todo list was identifying kinda of cars (like a police car), kinds of trucks (school bus and ambulance), and acting appropriately.
I've seen google mention responding to hand gestures from bicyclist. But also being exceedingly polite and repeatedly stopping as a track standing bicyclist rides slightly backwards and forwards.
Control: when to yield, without watching the face of the other driver, etc.
Edge cases: obeying a police officer, yielding to an ambulance, cooperating with other cars.