Waymo is shipping a software update to help its robotaxis navigate disabled traffic lights during power outages “more decisively,” the company said Tuesday in a blog post that explains why its self-driving vehicles got stuck at intersections during a blackout in San Francisco this past weekend. Waymo said the self-driving system in its robotaxis treats dead stop lights as four-way stops, just like humans are supposed to. That should have allowed the robotaxis to operate normally in spite of the massive outage. Instead, many of the vehicles requested a “confirmation check” from Waymo’s fleet response team to make sure what...