Waymo's robotaxis were uncertain about how to respond when the traffic lights in the city malfunctioned.

      On Saturday, Waymo's robotaxis faced a significant setback when a power outage impacting much of San Francisco created challenges for its autonomous vehicles in the area.

      Approximately 130,000 residents experienced power loss in their homes and businesses, while the outage also disabled traffic lights at key intersections, leading to confusion for Waymo’s robotaxis. Many of the self-driving cars halted at intersections, exacerbating congestion in addition to the disruption caused by the nonfunctional traffic signals.

      In response, Waymo halted its robotaxi services while awaiting the restoration of power and the affected traffic lights.

      “We have temporarily paused our ride-hailing services in the San Francisco Bay Area due to the extensive power outage,” Waymo stated on Saturday. “Our teams are working diligently in close coordination with city officials, and we are optimistic about resuming our services soon.”

      In a follow-up statement to Digital Trends on Sunday, Waymo indicated that it was in the process of resuming its robotaxi operations in the city, noting, “Although the failure of the utility infrastructure was considerable, we are dedicated to ensuring our technology adapts to traffic patterns during such situations. Throughout the outage, we maintained close coordination with city officials in San Francisco. We are focused on swiftly integrating the lessons learned from this episode and are committed to earning and preserving the trust of the communities we serve daily.”

      The outage, which was triggered by a fire at a Pacific Gas & Electric substation, began on Saturday morning, with power interruption occurring shortly after noon. By Sunday morning, power had been restored to approximately three-quarters of those affected in San Francisco.

      This concerning incident seems to highlight a vulnerability in the technology behind Waymo's robotaxis, as they struggled to manage the situation with nonfunctional traffic lights.

      Taking advantage of the situation, Tesla CEO Elon Musk commented on X that "Tesla robotaxis were unaffected by the SF power outage."

      Currently, Tesla's robotaxis operate with a safety driver who can take control of the vehicle at any time, while Waymo's robotaxis operate without a driver present.

      The differing technologies supporting their respective autonomous systems suggest that Tesla's vehicles may be better suited to adapt to a traffic light failure. For instance, Tesla cars use neural networks to process camera feeds and make human-like decisions in new scenarios, allowing them to operate without relying solely on maps. In contrast, Waymo utilizes LiDAR, radar, and updated HD maps, but, as demonstrated over the weekend, struggles with unexpected changes like a traffic light outage, which effectively converts a controlled intersection into a four-way stop.

      Waymo elaborated: “While the Waymo Driver is designed to treat non-functional signals as four-way stops, the scale of the outage caused instances where vehicles remained stationary longer than usual to verify the status of the affected intersections. This added to traffic congestion during peak times.”