There was an article a short while ago written by a journalist who rode in a driverless car for a stretch. There was one adjective that really stood out, an adjective that most people don't take into consideration when talking about driverless cars.
That one word: boring.
Driverless cars drive in the most boring, conservative, milquetoast fashion imaginable. They're going to be far less prone to accidents from the outset simply because they don't take the kind of chances that many of us wouldn't even begin call "risky". They drive the speed limit. They follow at an appropriate distance. They don't pull quick lane changes to get ahead of slowpokes. They don't swing around blind corners faster than they can stop upon detecting an unexpected hazard. They don't nudge through crosswalks. They don't cut off cyclists in the bike lane. They don't get impatient. They don't get frustrated. They don't get angry. They don't get sleepy. They don't get distracted. They just drive, in a deliberate, controlled, and entirely boring fashion.
The problem with so, so many of the "what if?" accident scenarios is that the people posing said scenarios presume that the car would be putting itself in the same kinds of unnecessarily hazardous driving positions that human drivers put themselves in every single day, as a matter of routine, and without a moment's hesitation.
Very, very few people drive "boring" safe. Every driverless car will. Every trip. All the time.