I also think that autonomous vehicles will be much safer than human-driven vehicles. We can keep making them better based on experience while on the other hand we would keep adding new inexperienced human drivers. I'm sure that we can correct any problems that we may find with early autonomous vehicles. I doubt that we'll ever be able to correct human distraction, emotional reactions, bad judgement and general stupidity.
Do you have any stats on the percentage of accidents caused by physical wear and tear on brakes rotors and axles? Or on the "other thousands of extraneous factors" that you've considered? How do those compare to the percentage caused by any sort of human error?
The following claims human error is the sole cause 57% of the time and a contributing factor 90% of the time, while mechanical fault is the sole cause only 2.4% of the time.