A postmortem from Waymo on Tuesday is offering at least some clarity about what the hell happened to its poor, benighted San Francisco operation after much of the power across the city went out on Saturday.
Waymo behavior at dark stoplights forced the Alphabet-owned company to call all its San Francisco robotaxis back home, a logistical catastrophe. But in fairness, social media posts probably made Waymo’s ad-hoc solution look even more haphazard than it actually was, giving the impression that all the Waymos in San Francisco had been zapped at the same time by whatever caused the outage, causing them to halt in place, including in busy intersections, as if their robot drivers had been raptured to robo-heaven.
Power outage took out the waymos RIP pic.twitter.com/DPte8oOGku
— Vincent Woo (@fulligin) December 21, 2025
There were certainly choked streets and blocked intersections, but below is how Waymo prefers to frame the way the problem arose. Note that in its comms, Waymo refers to the self-driving software in its cars as “the Waymo Driver.”
“While the Waymo Driver is designed to handle dark traffic signals as four-way stops, it may occasionally request a confirmation check to ensure it makes the safest choice. While we successfully traversed more than 7,000 dark signals on Saturday, the outage created a concentrated spike in these requests. This created a backlog that, in some cases, led to response delays contributing to congestion on already-overwhelmed streets.”
It seems very important to Waymo’s brand to not ever allow the impression that Waymos are ever remotely driven. What Waymo has instead of “remote drivers” or “teleoperators” is called “fleet response,” a Waymo blog post says. When the Waymo Driver encounters a truly heterogeneous driving situation, it sends out for human feedback, which we’re not supposed to think of as a bailout. It might want confirmation about, say, what it suspects is a completely impassable intersection, and a human operator sends back signals directing it where it might want to go.
“Fleet response can influence the Waymo Driver’s path, whether indirectly through indicating lane closures, explicitly requesting the AV use a particular lane, or, in the most complex scenarios, explicitly proposing a path for the vehicle to consider,” the Waymo blog post about Fleet Response says. You might or might not consider this the input of a “remote driver” or a “teleoperator.” Waymo clearly doesn’t.
At any rate, all these furtive Waymos at blacked-out stoplights in San Francisco on Saturday created a logjam of these requests for human feedback, and Waymo’s postmortem acknowledges that the logjam caused even worse traffic.
So what Waymo says happened next seems like a reasonable course of action in response to causing traffic during a blackout: “We directed our fleet to pull over and park appropriately so we could return vehicles to our depots in waves. This ensured we did not further add to the congestion or obstruct emergency vehicles during