A recent widespread power outage in San Francisco on December 20 led to Waymo robotaxis stalling and contributing to traffic congestion, sparking significant concerns regarding the preparedness of autonomous vehicle operators for major emergencies such as earthquakes and floods. The incident occurred after a fire at a PG&E substation resulted in a power loss to approximately one-third of the city, causing traffic lights to cease functioning. Videos shared on social media showed driverless taxis from Alphabet unit Waymo, a common sight on San Francisco streets, stuck at intersections with their hazard lights activated, highlighting a critical vulnerability in the nascent technology's real-world deployment.

Waymo subsequently halted its operations, resuming only a day later. The company stated that while its robotaxis are engineered to interpret non-operational traffic signals as four-way stops, the concentrated surge in confirmation requests from the Waymo Driver (its autonomous system) to human "fleet response" agents during the outage created an unforeseen challenge. Despite successfully navigating over 7,000 darkened signals previously, the sheer volume of these requests during the city-wide blackout led to response delays, exacerbating congestion on already overwhelmed streets. The industry practice of "teleoperation," where humans remotely monitor and control vehicles, came under scrutiny due to its limitations during such large-scale disruptions.

The incident has intensified calls for more stringent regulation of the rapidly expanding autonomous vehicle industry. Experts like Philip Koopman, a Carnegie Mellon University computer-engineering professor, emphasized that regulators must demand proof of adequate handling for scenarios like earthquakes if a blackout response proves insufficient. Missy Cummings, director of the George Mason University Autonomy and Robotics Center and a former U.S. road safety adviser, asserted the necessity for federal regulation of remote operations, urging the implementation of backup remote operations to manage catastrophic failures effectively, underscoring the vital role of human intervention when automated systems falter.

In response to the December 20 event, California's Department of Motor Vehicles (DMV) and the California Public Utilities Commission (CPUC), the primary regulatory bodies for robotaxi testing and commercial deployment, confirmed they are actively investigating the incident. The DMV indicated it is engaging with Waymo and other autonomous vehicle manufacturers to discuss emergency response protocols and is concurrently developing regulations to ensure that remote drivers meet rigorous standards for safety, accountability, and responsiveness, addressing the identified gaps in current operational frameworks.

The autonomous vehicle sector, which includes companies like Tesla and Amazon's Zoox expanding their services, has faced considerable challenges, including high investment costs and public backlash following collisions, leading some, such as General Motors' Cruise, to cease operations after permit revocations. Waymo, which evolved from Google's self-driving project in 2009, has steadily grown its fleet to over 2,500 vehicles, operating in several major U.S. cities. However, the San Francisco outage serves as a stark reminder of the complexities involved in scaling such technology responsibly.

To mitigate future occurrences, Waymo announced it is implementing fleet-wide updates designed to equip its vehicles with "specific power outage context," enabling them to navigate more decisively in similar situations. Both Koopman and Cummings advocate for additional permitting requirements for robotaxi operators once their fleets exceed a certain size, ensuring they possess the necessary capabilities to manage large-scale failures. This incident, described as "a shot across the bow," underscores the ongoing need for continuous refinement and robust regulatory oversight as autonomous vehicles become increasingly integrated into urban infrastructure.