Google employees pay attention to the road as the cars drive because that's their job. Consumers will read the paper and go to sleep while the cars drive. Manual override is not a solution to this problem. A panic mode that alerts the driver to take over in uncertain situations could help.
The cars will be programmed to always ensure that there is enough room to stop the car safely when something unexpected happens. BMW already has a system to automatically stop the vehicle safely if the driver is suddenly incapacitated. And Volvo has one that stops you rear-ending someone. Pretty soon we'll have cars that are pretty tough to crash, even though the human will still drive it almost 100% of the time.
Which is precisely why the 'hey we won't need insurance' call is completely wrong.
As long as people can override the function, people will make mistakes and cause damage. And this will always be the case, nobody wants to be stuck on an isolated road, unable to proceed because their lane is partially blocked, but it is safe to cross the lane and proceed.
