The article linked by TTT concludes with the rather important statement that we shouldn't "let perfect be the enemy of good". In this case too it applies because it seems that people are determined to apply perfection to computers and, if (when) they fail to reach that, rely on humans instead. But humans already fail. Badly. A lot. And fatally. And the question only becomes: "are computers better than humans, such that computer-controlled cars will be, on the whole, safer?"
We are probably yet to discover a question to which the answer is, definitively and for all time, that humans are better. Driving is likely to fall victim to the same progress in time.