It seems it was driving pretty slow (17MPH) and they do tend to put in a pretty big gap to the right side when they can.

There are kinds of human sensing that are better when humans are maximally attentive (seeing through windows/reflections). But there's also the seeing-in-all-directions, radar, superhuman reaction time, etc, on the side of the Waymo.

17MPH is way to fast, depending on the details. I do not think the article gives the details to know if it was a reasonable speed to be going or not, enough details to know it might be to fast, like proximity to a school and children present, yes.

And the fact that Waymo is never drunk/high/tired/texting, which an astounding portion of human drivers are.