The lack of electricity turns off the traffic lights and Waymo robotaxis in San Francisco stop, blocking traffic. The episode reopens the debate on the safety of autonomous vehicles. Alphabet announces technology updates and new emergency protocols.
Blackout a San Francisco, robotaxi Waymo in tilt
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A large blackout that hit San Francisco before Christmas also put the robotaxi at Waymoreviving concerns about the capacity of self-driving vehicles to manage emergency situations on a large scale, such as earthquakes or floods.
The blackout was caused by a fire at a Pacific Gas and Electric (PG&E) substation, which caused “significant and extensive damage” and left about 130,000 customers without electricity at peak hours. According to PG&E, the outages began early Saturday afternoon and peaked about two hours later. On Sunday morning, around 21,000 customers were still without power.
With traffic lights and street signs out of order in numerous areas of the city, San Francisco has been hit by a widespread traffic congestion. Videos posted on social media showed several Waymo self-driving vehicles stuck at intersectionswith the emergency lights on, contributing to road congestion. In response to the situation, Waymo decided to temporarily suspend service, resuming operations the following day.
The difficulties of autonomous systems and the key role of remote assistance
Waymo explained that its vehicles are designed to handle inoperative traffic lights even at four-stop intersections. However, in some cases, the system requires verification by human operators. “Although vehicles successfully navigated more than 7,000 unlit traffic lights that day, the outage created a concentrated spike in requests for confirmation”, we read in a note released by the company and reported by Reuters. This has led to delays in responses that “they contributed to congestion on already overloaded streets”.
Waymo’s robotaxis, like those of other operators globally, use a system of teleoperationthat is to say remote assistance by humans. In the case of Waymo, a team of “fleet response agents” intervenes when the Waymo Driver – the autonomous driving system – encounters complex situations.
Second Missy Cummingsdirector of the Autonomy and Robotics Center at George Mason University and former consultant to the US federal traffic safety regulator, the episode demonstrates the need for more stringent rules. “The whole point of remote operations is for humans to be there when the system isn’t responding as it should”, said the expert, who underlined: “The federal government must regulate remote operations. It must ensure that there are backup operations when a catastrophic failure occurs”.
The Californian authorities have started investigations into the accident. The California Department of Motor Vehicles (DMV) and the California Public Utilities Commission, responsible for regulating and permitting robotaxis, said they were looking into what happened.
The DMV said it is in contact with Waymo and other autonomous vehicle manufacturers to discuss emergency response actions. It also announced that it is developing new regulations to ensure that remote drivers “meet high standards of safety, responsibility and responsiveness”.
The three countermeasures announced by Waymo
Three days after the blackout, Waymo announced a series of updates to make the fleet better prepared for similar events in the future. “We have always focused on developing the Waymo Driver for the world as it is, even when infrastructure fails,” the company wrote in an official blog post published Tuesday evening.
Waymo explained that it had ordered the fleet to “pull over and park appropriately” during the emergency, and then returning the vehicles to the depots “in waves”, so as to “do not add further congestion or impede emergency vehicles during the most critical phase of recovery.”
The company announced three “immediate steps.” The first concerns software updates extended to the entire fleet to provide vehicles “more specific context on local power outages”, allowing faster and safer decisions at intersections. The second provides the strengthening emergency response protocols and greater collaboration with the San Francisco mayor’s team, Daniel Lurieto improve joint preparedness. The third intervention concerns updating training for first respondersintegrating lessons learned from this and other large-scale events.
A rapidly expanding sector, but under observation
The incident comes at a time of strong expansion for Waymo. The company, controlled by Alphabet, manages a fleet of over 2,500 vehicles and operates in the San Francisco Bay Area, Los Angeles, Phoenix, Austin and Atlanta. In 2025 it surpassed an estimate of 450,000 paid trips per week and declared that he had carried out 14 million trips during the yearwith the aim of exceeding 20 million total trips since the start of the service in 2020.
The fleet grew from around 1,500 robotaxis in May 2025 to around 2,500 at the end of November. Waymo today carries out more 250,000 paid trips per week.
At the same time, the company is expanding collaborations with Uber in Atlanta and Austin, launched a corporate travel program and trial with DoorDash for self-delivery in Los Angeles, Phoenix and San Francisco. Waymo has also started service on highways in some cities and announced new expansions, including Detroit, Miami and several other US cities, with the aim of launching fully autonomous commercial services in 2026.
Despite the criticism, the Mountain View company reiterates its confidence in the project. “Backed by more than 100 million miles of fully autonomous driving experience and a record of improving road safety, we are undaunted by the challenge of questioning the status quo of our roads”, we read in an official note, underlining that we want to continue to serve residents and visitors of San Francisco.
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