The blackout, triggered by a fire at a PG&E substation on December 20, knocked out power to roughly one-third of the city. Videos shared on social media showed Waymo robotaxis stranded with hazard lights on while traffic signals were inoperable, creating congestion on already busy streets. Waymo temporarily halted its services, resuming operations the following day.
The incident has intensified calls for stricter regulation of the rapidly growing robotaxi industry, which includes competitors such as Tesla and Amazon’s Zoox, as they expand services across multiple cities.
“If you get a response to a blackout wrong, regulators are derelict if they do not require proof that scenarios like earthquakes will be handled properly,” said Philip Koopman, a Carnegie Mellon University computer engineering professor and autonomous-technology expert.
Waymo responded that its robotaxis are designed to treat non-operational traffic signals as four-way stops but occasionally request confirmation checks. During the blackout, “the outage created a concentrated spike” in these requests, which “led to response delays contributing to congestion on already-overwhelmed streets,” the company said. Its vehicles successfully navigated more than 7,000 darkened signals that day.
Autonomous vehicle operators commonly rely on human oversight—known as teleoperation—to monitor and assist vehicles remotely. Waymo employs a team of “fleet response” agents who can guide vehicles when the system encounters unusual situations. However, experts warn that the San Francisco outage highlights the need for clear regulations on how such remote support is managed.
“The whole point of having remote operations is for humans to be there when the system is not responsive as it should be,” said Missy Cummings, director of the George Mason University Autonomy and Robotics Center and former U.S. road safety adviser. “The federal government needs to regulate remote operations and ensure backup systems are in place for catastrophic failures.”
California regulators, including the Department of Motor Vehicles and the Public Utilities Commission, have confirmed they are investigating the incident. The DMV stated that it is consulting with Waymo and other autonomous vehicle companies on emergency response protocols and is developing rules to ensure remote operators meet “high standards for safety, accountability and responsiveness.”
Robotaxis face ongoing regulatory and operational hurdles
Deploying fully autonomous vehicles has proven more complex than anticipated, with high investments required for safety and public backlash following accidents. A high-profile 2023 incident involving a Cruise robotaxi, which struck a pedestrian, led regulators to revoke the company’s permit and temporarily halt operations.
Despite these challenges, robotaxis are regaining attention. Tesla recently launched its service in Austin, Texas, and Waymo continues to expand gradually, operating over 2,500 vehicles across San Francisco, Los Angeles, Metro Phoenix, Austin, and Atlanta.
Waymo said it is updating its fleet protocols to include “specific power outage context,” enabling vehicles to navigate more decisively during blackouts. Experts, however, argue that larger fleets should face additional permitting requirements to ensure adequate emergency response capabilities.
“If this had been an earthquake, it would have been a problem,” Koopman said. “This is just a shot across the bow.”