There are fairly automated trains but only in very controlled and low-speed environments. (e.g. "people movers" at airports).
But, to the broader point, I can't help but feel that a lot of people are conflating "able to tool down 280 with a human on board who is fully capable of taking over control--albeit not instantaneously" (or a next gen cruise control, if you would) with "a robot chauffeur who can drop the kids off at soccer practice." The second problem--which includes dealing with all the unpredictable things that happen on secondary roads--would seem to be enormously more difficult than the first.
But, to the broader point, I can't help but feel that a lot of people are conflating "able to tool down 280 with a human on board who is fully capable of taking over control--albeit not instantaneously" (or a next gen cruise control, if you would) with "a robot chauffeur who can drop the kids off at soccer practice." The second problem--which includes dealing with all the unpredictable things that happen on secondary roads--would seem to be enormously more difficult than the first.