SAN FRANCISCO, December 22, 2025 — Waymo is rolling out a fleet-wide software update after a weekend power outage in San Francisco exposed a vulnerability in its autonomous system, halting robotaxi service as driverless cars became stranded at darkened intersections across the city. The incident underscores the challenges of deploying fully autonomous vehicles in real-world conditions, even in tech-forward cities.
Software Update Aims to Navigate Blackouts
The update will help Waymo’s self-driving software better respond to widespread power outages, allowing vehicles to navigate intersections more decisively without overwhelming its remote assistance system.
The need for the update followed a weekend outage that left nearly a third of San Francisco—approximately 130,000 households—without electricity and disabled traffic signals citywide. The resulting gridlock left multiple Waymo vehicles stopped or stationary on busy streets. Videos circulating on social media showed the immobilized vehicles adding to congestion as police and fire crews worked to manage traffic manually.
The blackout began Saturday afternoon after a fire at a PG&E substation in the South of Market neighborhood. Waymo proactively paused operations Saturday evening as the outage intensified, coinciding with one of the busiest shopping weekends of the year. The company stated it worked with San Francisco officials throughout the event, safely moving vehicles to depots or the sides of roads.
Robotaxi Service Resumed After Power Restoration
Service resumed Sunday evening after power was restored to most neighborhoods, though thousands of customers remained without electricity and PG&E crews continued repairs into Monday following what the utility described as “significant and extensive” damage at the substation.
Waymo explained its vehicles are designed to treat dark signals as four-way stops, but the scale of the outage caused cars to remain stationary longer than usual as they attempted to confirm intersection conditions amid widespread signal failures. This pause marked a significant disruption for Waymo in its home market, where it operates fully driverless ride-hailing services.
As of late 2025, Waymo has emerged as the leading commercial robotaxi operator in the U.S., running fully driverless services in five major cities—Phoenix, Los Angeles, Austin, Atlanta, and San Francisco—and logging more than 100 million autonomous miles and over 14 million paid rides. The company operates a fleet of over 1,500 vehicles and plans to expand to more than two dozen additional cities by the end of 2026.
What happens when a self-driving car encounters a non-functioning traffic light? Waymo vehicles are programmed to treat it as a four-way stop, but large-scale outages can overwhelm the system’s ability to confirm intersection safety.
Despite data showing lower crash rates compared to human drivers, Waymo has faced scrutiny following incidents including collisions with cyclists and vehicles, animal fatalities, software-related traffic violations, and disruptions tied to infrastructure failures. The San Francisco incident has intensified concerns among residents and lawmakers about how autonomous vehicles handle “edge cases,” such as large-scale power outages, and whether current technology is ready for rapid expansion.
“We resumed ride-hailing service in the San Francisco Bay Area on Sunday,” a Waymo spokesperson said. “Saturday’s power outage was a widespread event that caused gridlock across San Francisco, with non-functioning traffic signals and transit disruptions. While the failure of the utility infrastructure was significant, we are committed to ensuring our technology adjusts to traffic flow during such events.”
The spokesperson added, “Throughout the outage, we closely coordinated with San Francisco city officials. We are focused on rapidly integrating the lessons learned from this event, and are committed to earning and maintaining the trust of the communities we serve every day.”
