Google said that the cars were always manned, and could be taken over in an instant by a driver.
Of course, a self-driving car would be convenient and decreasing the number of deaths caused by road accidents is an important issue, but assuming that this will be a feature of the self-driving cars, if, for some reason, the car needed to be driven manually, how many people would be skilled enough to take the wheel, especially in the case of an emergency?
If cars are being driven automatically, then the number of skilled drivers would decrease simply because people are becoming reliant on its ability to drive itself. This becomes not really a case where humans are lazy creatures (which they are), but a case where humans are increasingly
dependent and
reliant on technologies that requires less training meaning that in the process of gaining more advanced technologies, the general population would be falling backwards in terms of skill.
Having such complex programming in a car, it can probably also be sabotaged by whoever wanted to cause trouble, in a worst-case scenario, it can potentially be used for murder or manslaughter.
It's a good idea and all, but it should probably be released to those with a justified reason to have it, rather than allowing it to be used for minors and would be drunk drivers - after all, like I said before, in the case of an emergency, how would they drive?