A widespread power outage in San Francisco has renewed concerns about whether robotaxi operators are prepared to handle major emergencies such as earthquakes or floods, after dozens of autonomous vehicles from Waymo stalled in traffic earlier this month.
The outage, caused by a fire at a PG&E substation on December 20, knocked out electricity to roughly one-third of the city. Videos posted on social media showed Waymo’s driverless taxis stopped at intersections with hazard lights flashing as traffic signals went dark. Waymo temporarily halted operations and resumed service a day later.
The incident has intensified calls for tighter oversight of the fast-growing robotaxi industry, as companies such as Tesla and Zoox race to expand autonomous ride-hailing services across multiple U.S. cities. Philip Koopman, a computer engineering professor at Carnegie Mellon University, warned that failures during a blackout raise serious questions about how such systems would cope with more severe disasters. He said regulators should demand proof that large-scale emergency scenarios can be handled safely.
Waymo said its vehicles are designed to treat non-functioning traffic lights as four-way stops, but in some cases they request human confirmation. While its robotaxis successfully navigated more than 7,000 darkened intersections, the company said the outage caused a surge in confirmation requests that led to response delays and worsened congestion on already overwhelmed streets.
Robotaxi operators rely on varying levels of human remote assistance, known as teleoperation, to monitor and intervene when autonomous systems encounter uncertainty. Waymo uses human “fleet response” agents who assist its automated driving system in complex situations. However, Missy Cummings, director of the George Mason University Autonomy and Robotics Center and a former adviser to U.S. road safety regulators, said the incident highlights the need for stricter rules governing remote operations and backup systems during catastrophic failures.
California regulators have taken notice. The California Department of Motor Vehicles and the California Public Utilities Commission said they are reviewing the incident and discussing emergency-response measures with Waymo and other autonomous vehicle developers. The DMV added it is drafting rules to ensure remote drivers meet high standards for safety, accountability and responsiveness.
Experts say the outage serves as a warning as robotaxi fleets grow larger. Koopman said additional permitting requirements may be needed once companies reach a certain scale, arguing that what happened in San Francisco should be seen as an early signal rather than an isolated glitch. “If this had been an earthquake, it would have been a problem,” he said.
