Waymo plans a fleetwide software update after a widespread San Francisco power outage caused traffic lights to fail and some robotaxis to stop at intersections. The company said its Waymo Driver system is designed to treat dark signals as four-way stops, but the outage created a surge in confirmation checks that slowed decisions and contributed to congestion. Service was paused in affected areas and resumed after conditions stabilized, while internal teams reviewed the event. Waymo also notified city emergency teams.
Waymo said the update will add context about power failures so vehicles can navigate when signals go dark and support demand spikes. The company is also adjusting incident response playbooks, including escalation paths with local officials and faster vehicle repositioning when traffic deteriorates. The outage was caused by a fire at a PG&E substation and affected roughly 130,000 customers, shutting down thousands of traffic signals across parts of the city. Waymo said it traversed more than 7,000 dark signals. California regulators are reviewing the disruption, and the episode follows other scrutiny of autonomous driving systems, including software fixes tied to separate edge cases. Waymo said service resumed the next day and the changes will roll out across its U.S. fleet.
Why it matters
The incident shows how rare infrastructure failures can expose operational risk for robotaxi services and drive software and emergency-protocol changes with regulatory visibility.
Source Attribution
Source: The Wall Street Journal | Adapted & summarized
Published on: 27 December 2025
Category: Automotive
Region: USA
