> The default reaction for a Waymo car under any sort of ambiguity seems to be to just stop (literally) until the ambiguity resolves itself. Unfortunately this causes considerable confusion and traffic backups for human drivers.

Honestly, to me this just sounds like the waymo cars being better drivers than humans and not breaking traffic rules and endangering others. Just like complaining about new drivers or driving school drivers for being "too slow", while in reality they are just the only ones not going over the speed limit and not shoving into lanes hoping others will compensate.