Waymo Updates Software After Blocking Emergency Vehicles and SF Blackout
- A massive blackout disabled traffic lights, causing Waymo cars to flood their remote support team with confirmation requests, overwhelming the system.
- Degraded cellular networks delayed human intervention, leaving cars frozen in "fail-safe" mode in the middle of busy intersections.
- Waymo is updating its software to allow cars to navigate outages more independently and improving coordination with city emergency services.
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| Photo by Hoseung Han on Unsplash |
A massive power outage in San Francisco last Saturday exposed a critical vulnerability in Waymo’s autonomous fleet, turning a citywide inconvenience into a chaotic gridlock. The blackout, caused by a fire at a PG&E substation, disabled traffic lights across the city. While Waymo’s software is programmed to treat a single dark signal as a four way stop, the simultaneous failure of hundreds of signals triggered a "concentrated spike" in confirmation requests. Essentially, the cars, overwhelmed by the scale of the anomaly, phoned home for human guidance. However, the blackout also degraded local cellular networks, delaying these remote commands and leaving vehicles frozen in intersections, blocking buses and impeding emergency responders.
The fallout was immediate and severe. City officials, including District 5 Supervisor Bilal Mahmood, described a "compounding loop" of failure the fire caused the outage, the outage froze the robotaxis, and the frozen robotaxis hindered the fire department’s ability to respond to the initial fire. Reports flooded the city's 311 line, citing Waymo vehicles blocking arterial roads like Divisadero and Geary. Experts suggest the cars entered a "fail safe" mode defaulting to a stop rather than risking an unsafe maneuver. While safer than driving aimlessly, this default behavior becomes disastrous when hundreds of vehicles execute it simultaneously in active traffic lanes.
In response, Waymo is rolling out a fleet wide software update designed to provide vehicles with "specific power outage context," allowing them to navigate dark signals more decisively without waiting for human confirmation. The company is also overhauling its emergency response protocols to better coordinate with city officials during large scale infrastructure failures. Despite the chaos, Waymo emphasized that its fleet successfully traversed over 7,000 dark signals during the event, arguing that the stalls were limited instances in an otherwise functional system. However, the incident has reignited the debate over whether autonomous fleets are truly ready for "edge cases" rare, catastrophic events where the digital and physical infrastructure collapse together.