A sudden large-scale power outage rendered the world's most advanced autonomous driving systems temporarily "inoperable." On the evening of December 21 local time, a widespread power failure in San Francisco caused by a fire at Pacific Gas and Electric Company (PG&E) substation led to a complete shutdown of Waymo's Robotaxi service in the city—numerous driverless vehicles were stuck in the middle of roads and intersections, causing serious traffic congestion, with social media flooded with videos showing people "stuck by AI cars."
According to footage captured by witnesses, multiple Waymo self-driving cars remained motionless, leaving human drivers behind unable to move forward, forced to detour or wait for long periods. San Francisco Mayor Daniel Lurie urgently called on residents to "avoid non-essential travel," as the power outage also caused traffic lights to fail and Muni public transport to stop, bringing the city's transportation system almost to a standstill.
Waymo Temporarily Halts Services, but Does Not Explain "Why Power Outage Led to System Failure"
Waymo spokesperson Suzanne Philion confirmed that the company has "temporarily suspended all ride-hailing services in the San Francisco Bay Area" and is closely coordinating with the city government to assess infrastructure recovery. However, the company did not explain why a regional power outage caused its vehicles to fail collectively, triggering widespread industry skepticism.
Three Possible Causes Expose System Vulnerabilities
1. Reliance on Connected Traffic Light Data: Waymo vehicles highly depend on V2X (vehicle-to-everything) systems to obtain traffic light status. A power outage caused traffic lights to go dark, leaving the AI unable to determine right-of-way, triggering a safety stop mechanism;
2. Cellular Network Disruption: Autonomous driving relies on 5G/4G for real-time updates of high-definition maps and remote monitoring. A power outage may cause communication interruption, leading vehicles into "safety silence" mode;
3. Remote Operation Center Unreachable: When vehicles encounter complex scenarios requiring manual intervention, a power outage prevents the remote control center from responding, so the system chooses to park in place.
The Achilles' Heel Amid Rapid Growth
This incident occurred during Waymo's period of rapid business expansion—according to leaked documents from Tiger Global, its weekly order volume has already reached 450,000, nearly double the level of spring. However, a city-level power outage brought this "fleet of unmanned vehicles" to a standstill, exposing the current L4-level autonomous driving's high dependence on urban digital infrastructure, highlighting a significant gap between it and true "all-weather, all-scenario" operations.
Industry Warning: Intelligent Transportation Cannot Rely Only on Vehicle Intelligence
