For self-driving cars, the human in the loop can’t always answer the phone. Last weekend, a gnarly power outage in San Francisco took out a number of traffic lights, which, in turn, sent a number of self-driving Waymo robotaxis into a sort of fugue state. Instead of driving, some of the Waymos responded to these now-analog intersections by turning on their hazard lights, blocking traffic, and, well, not doing much of anything. There were multiple instances of Waymo cars clogging up roads, turning futuristic technology into glorified bollards. The city quickly asked the company to turn off the service.