After giving the driverless Google car much consideration and thought I have come to an interesting conclusion.
First, a computer controlled driverless car is programmed to scrupulously follow the rules of the road. Although technically this is a good thing, this is where the problems will arise.
Most people who drive are barely aware of what the rules of the road are and typically only follow them when it is convenient for themselves.
On the other hand a computer controlled driverless Google car that is programmed to scrupulously follow the rules of the road will be confounded by the behavior of human beings in control of cars.