Do waymos perhaps pass through behind a vehicle much faster/closer than a human driver? That would appear like one of those things that "computer accuracy" could do that humans would never try.

A cyclist confident to be able to keep up with the truck's acceleration might go not only for the physical slipstream, but also for the "traffic slipstream", remaining so close that he would never intersect paths with a regular driver. That would be breaking traffic rules, not arguing that, but it would not only be safe (-ish, truck might hit the brakes) but also not inconvenience any drivers who wouldn't pass behind the truck without leaving a sufficient gap anyways. Until a waymo shows up and ends that assumption (this is speculation, I don't know how waymos drive)

In any case, from a continental European perspective the American four-way stop just seems completely wrong, despite priority to the right being essentially the same when fully saturated.