I'd be willing to bet that most of the difference in crash rates between Waymos and human drivers can be explained by the fact that Waymos drive under the speed limit.
David ZipperIIHS—the closest thing in the US to a neutral arbiter on AV safety— has found that Waymos are involved in ~68% fewer crashes than human drivers. That's a big deal, although the safety benefits appear to be lower than what Waymo has publicly claimed. A few thoughts 🧵