The reported disengage rate has improved a lot, but Waymo only reports disengagements it classifies as "related to safety", based on proprietary analysis and counterfactual simulations it does not share.
This isn't really true. You may be thinking about the CA required disengagement report rules. From a recent waymo safety report:
"In this paper, “disengagement” refers to any event in
which the AV’s automated driving mode is disengaged.
This is broader than the definition used in certain
California state regulations, where the term more narrowly
refers to certain safety-relevant disengagements."
What about the accident rate per miles driven? If that is dropping too I'd see that as confirmation that it really is improving. If that isn't then it's just bookkeeping.
You can read all California autonomous vehicle accident reports here.[1]
Most Waymo reports are "stopped in traffic, was rear-ended". There are two reports this year where the Waymo vehicle was responsible. In both cases, it was backing up while doing a three-point turn in a narrow street and bumped into something at 2MPH. So they need better sensor coverage in back.
