The hardest thing about driving in Boston is that the streets are wildly non-rectilinear. Waymos obviously don't understand "the rules of the road," they are exhaustively trained on the rules of the road until they can imitate them. For rectilinear intersections they can transfer this training to a variety of different streets; not so in Boston, where you might have a weird three-way intersection involving oblique angles. I am also not sure if SF / Phoenix have many roundabouts. Or, near me, this horrific pair of four-way-intersections somehow combining into a five-way(?) intersection: https://www.google.com/maps/place/42%C2%B022'50.0%22N+71%C2%... I suspect Waymo would get badly confused here unless it was directly trained on this specific intersection.
There is plenty of stuff in SF that's brain-freeze level for human drivers. From rectilinear grid "improved" with a million specialized lane markings to plenty of vehicles blocking traffic short of ingenuity.
There are some odd intersections in Phoenix. And don’t even ask about the “suicide lanes” which change from turning lanes to unidirectional during rush hour with the direction depending on time of day. AFAIU Waymo drives everything in their coverage area ahead of rollout so they’re definitely “training” on oddities.
The hardest thing about driving in Boston is that the streets are wildly non-rectilinear. Waymos obviously don't understand "the rules of the road," they are exhaustively trained on the rules of the road until they can imitate them. For rectilinear intersections they can transfer this training to a variety of different streets; not so in Boston, where you might have a weird three-way intersection involving oblique angles. I am also not sure if SF / Phoenix have many roundabouts. Or, near me, this horrific pair of four-way-intersections somehow combining into a five-way(?) intersection: https://www.google.com/maps/place/42%C2%B022'50.0%22N+71%C2%... I suspect Waymo would get badly confused here unless it was directly trained on this specific intersection.