Re: Reaction time?
My fear for early models would be stuttering - identifying too many items as threats/obstacles in an effort to live up to safety hype and making for a bumpy ride during real road conditions.
The lack of manual navigation functions is somewhat of a concern, but not overwhelmingly. How will it deal with things like driveways, or new construction? Someone earlier mentioned requiring all cars to have self driving features added, but it could go beyond that - requiring all cities to update a database about road construction, maintenence, traffic stops/police dragnets, etc. How much bureaucratic overhead are we willing to accept to make texting in the car legal again? ;)
Also, car hackers/hijackers could become a thing.