Power Outage Halts Waymo Robotaxis in San Francisco

A massive power outage struck San Francisco over the weekend, affecting as much as a third of the city and leaving more than 130,000 homes without power. The outage began Saturday afternoon following a fire at a local substation. Critical city systems were impacted, including traffic signals, which caused significant disruptions for autonomous vehicle operations.

Waymo's fleet of robotaxis was particularly affected by the loss of traffic lights. The autonomous vehicles, which rely on a combination of high-resolution maps and sensor inputs, were paralyzed and stopped in their tracks. This malfunction contributed to traffic clogging throughout the affected areas. The incident highlights the challenges autonomous vehicle technology faces during infrastructure failures.

The disruption began on Saturday afternoon with a fire at a substation in the city. This fire triggered a widespread blackout that at times affected as much as a third of the city. The outage left more than 130,000 homes without electricity.

Critical systems across the city were compromised by the loss of power. Among the most visible impacts was the failure of traffic lights, which created hazardous conditions and contributed to gridlock. The loss of signal control is a significant challenge for any driver, human or machine.

The failure of traffic signals directly paralyzed Waymo's fleet of robotaxis. Without functioning traffic lights to guide them, the autonomous vehicles stopped in their tracks. This halt in operation contributed to the clogging of traffic in the affected areas.

Waymo operates a significant number of vehicles in the region. The company has more than 800 AVs in its Bay Area fleet. These vehicles are typically seen navigating the city streets of San Francisco.

The affected vehicles are modified Jaguar I-Paces. These cars are equipped with extensive sensor arrays, including:

• High-resolution mapping systems
• Lidar sensors
• Optical sensors

These sensors allow the vehicles to navigate by combining real-time inputs with pre-mapped data. However, the vehicles are programmed to drive conservatively.

Autonomous vehicles rely heavily on infrastructure to function correctly. The incident in San Francisco demonstrates how edge cases—unexpected scenarios like a total loss of power—can challenge the technology. When traffic lights go out, the vehicles must rely on other rules and sensors to proceed, which can lead to confusion.

Waymo has faced other safety challenges recently. Earlier this month, the company issued a recall to address a specific software problem. That issue caused robotaxis to illegally pass stopped school buses. The recall was intended to fix the problem and improve safety compliance.

The event underscores the prevalence of autonomous vehicles in the Bay Area. Visitors to San Francisco frequently observe the fleet of sensor-festooned vehicles. The cars are easily identified by their all-white color and the equipment mounted on the roof.

While the fleet size is over 800 vehicles, the presence on the road can feel even higher. It is common to see multiple vehicles, often with no occupants, within a single block. The density of these vehicles means that any operational failure has a noticeable impact on local traffic patterns.

The weekend power outage in San Francisco exposed a vulnerability in autonomous vehicle operations. Waymo robotaxis were unable to navigate the city when traffic lights failed, resulting in stopped vehicles and increased traffic congestion. As the Bay Area continues to integrate these vehicles into its transportation network, the reliability of underlying infrastructure remains a critical factor for safe and efficient operation.