Waymo's record is only "safer than humans" because they haven't had a fatality yet and thus get 0/x, anything can be "safer than humans" by that count.

I looked up what numbers I could find, according to the OECD's Road Safety Annual Report 2016, in 2014 the US averaged about one death per 150 million vehicle-kilometers (vkm) (6.7 killed per billion vkm).

According to Waymo's own page on the subject, they have driven "more than 5 million miles" (8mvkm) since 2009[0] and they seem to be by far the lead vkm producer in the autonomous space[1]. Just to be as safe as 2014 US human driving they need to clock in an other 140mvkm with no more than one fatality, and even then that could be debated to be in more selected conditions than human driving.

Don't get me wrong, I'm a big believer in autonomous driving and I think it would be a great, great thing, but saying it is already safer than human driving is at best misleading.

[0] https://waymo.com/ontheroad/

[1] https://www.theverge.com/2018/1/31/16956902/california-dmv-s...

Yep, it's like the study done by US government on the chances of accidental detonation of any of their nuclear weapons - and basically the study concluded that the chances are zero, because it hasn't happened yet(the study also found that the cold-war era weapons had no locks, no redundant fail safe mechanisms, and could be detonated by literally anyone who got their hands on one - but hey, none of them were so they must be safe!)