This is awesome and revolutionary. No more looking for parking spots- just send the car to the nearest garage or back home. Also the cars could coordinate to minimize traffic. So many possibilities!
Given the current state of the technology, this makes sense. And in the future, we may yet have fully driverless cars, instead of merely autonomous ones.
Edit: The way google has been testing these cars, AFAIK, is through a special "experimental vehicle" permit.
I have a few concerns about the short term ramifications.
1) The person behind the wheel can't do work, read, eat, or apply make-up if their primary responsibility is to second-guess the computer. So the most tantalizing benefit of being driven wherever you want is going to have to wait until some future day.
2) A vehicle that obeys the speed limit and makes a full stop at stop signs is going to infuriate some drivers. They should probably avoid matching the speed of adjacent cars when possible, to prevent blocking aggressive drivers that want to pass. These cars are probably going to avoid the fast lane.
3) I can see plenty of scenarios where an autonomous vehicle acts safely but still gets in an accident. Slowing to avoid a collision could result in being rear-ended, or a human driver might merge into the car because he failed to check his blind spot. So there will be accidents. I assume the cars will have to be rigged with video cameras and telemetry to prove that the car's programming was not at fault.
Actually I remember hearing somewhere that Japan uses a 50/50 split for all accidents, without working out who's to blame, to encourage everyone to be more responsible. They'll definitely have to tweak the cars driving styles per region. I'm now actually pessimistic that this will ever leave the USA any time soon, given how long it seems for even simple things to make it out.
More thoughts on speed-matching the car in your blind-spot: there are many, many things that can go wrong, even if a car has omnidirectional visual information. If a tire blows, you have to compensate. I wonder how much sway-room a computer needs to retake-control/move the car off the road.
As a sibling comment said, this is unsafe. The Google car actively avoids being in another car's blind spot as much as it can.
Keeping the left lane moving faster is probably wisest, but it's going to infuriate the drivers behind the autonomous vehicle, even though they're in the slow lane.
How far would a car go to avoid being rear-ended? Would a tailgater be able to cause the car to accelerate? At what point would the car stop trying to avoid an accident because it's safer to get rear ended than continue avoiding? When you put these things on the road, human drivers are going to start messing with them.
Also, what's the benefit to the owner/operator? Are you allowed to pay less attention to the road so you can be doing something else 99% of the time? Are you allowed to talk on the phone? If neither of these is true, then the legislation might put the cars' developers on more sure legal footing, but would appear to negate the primary utility of an autonomous vehicle.