After San Francisco's Fourth of July fireworks ended, more than a dozen Waymo robotaxis sat stranded in gridlock with drained batteries. Two drove directly into live pyrotechnics. No one was hurt.
After San Francisco's Fourth of July fireworks show let out near the Golden Gate Bridge, more than a dozen Waymo robotaxis sat silent and locked along the post-event exit route. Some waited so long in traffic that their batteries ran out. Tow trucks hauled them off on flatbeds.
The stranding was confirmed by Waymo on the record and corroborated by NBC Bay Area. A Waymo spokesperson attributed the mass immobilization to "major traffic disruptions, a high volume of travelers, and unplanned road closures." The mayor's office said more than 100,000 people were in the area at the time.
Two vehicles in the same corridor did something more consequential than stalling. They drove into active fireworks.
On the 1200 block of Connecticut Street, an unoccupied Waymo passed over a small firework that exploded underneath it. The vehicle caught fire and was extinguished by San Francisco firefighters before the flames spread. The car, a Jaguar I-PACE, the electric SUV Waymo uses for its service, was removed from the road. A Hoodline reporter at the scene described the block as quiet in the minutes before the car ignited, with no crowd nearby.
In a separate incident the same evening, a Waymo with a passenger aboard rolled over a bursting firework at an intersection. Passenger video reviewed by the San Francisco Chronicle shows the firework detonating under the front wheels. The passenger asks, on camera, "Are we on fire?" The car did not stop. It did not catch fire. The rider was unhurt.
The two outcomes, one a burned-out shell and the other an unmoved ride, are the same failure viewed at different severities. Both cars encountered a hazard category their system had not been taught to recognize: a live pyrotechnic on the road surface. In one, the unseen blast produced damage the car could not prevent. In the other, the same blast produced no damage but no stopping response.
Waymo markets its system as engineered for dense urban traffic and for pulling over or rerouting when conditions break from the planned route. The July 4 corridor was the kind of break those design choices are meant to absorb. The fleet absorbed most of it by stopping. Two of the cars absorbed none of it by continuing.
In its post-incident statement, Waymo said it "will evaluate what happened and study how to prevent such issues in the future." The language is the same form the company has used after past operational incidents, and it stops short of a public commitment to a specific detection rule for pyrotechnics, projectile-style ground hazards, or any new event-trigger threshold.
The next data points to watch are predictable. Whether the California Department of Motor Vehicles or the Public Utilities Commission, which regulates Waymo's driverless deployment permit, opens a review of the stranding and the fires. Whether Waymo publishes an updated hazard classifier that names pyrotechnics or ground-level projectile hazards. Whether event data from the Connecticut Street car or the intersection car is released, the way airlines release flight-data readouts after an incident.
The fleet did what it was taught on July 4. Whether Waymo's next software release treats a live pyrotechnic as a stop-or-swerve event is the next data point worth tracking.