Driving is definitely an art. NOBODY follows the law. 4 way stop - there are no rules. Traffic circles - people make up their own rules. Make a left turn from the straight-only lane? Sure, why not. Driverless cars would probably work great in areas with little or no traffic (long haul trucking), but I can't imagine a car driving itself in dense city traffic. How does one program a car to slowly change lanes in a "get the fuck out of my way or I'm going to hit you" fashion? That's how lane changing works in the city. If you wait for a space, you'll never be able to change lanes. The driver needs to create that space.
I like the idea of these Google cars driving exactly the speed limit. We should put millions of these cars on the road and completely fuck up the flow of traffic. Maybe that would be the kick needed to abandon our ridiculously stupid speed limits.