San Francisco mayor Daniel Lurie has called on California's state transport regulator to tighten rules for autonomous vehicles, following a July 4 incident in which Waymo robotaxis stalled in heavy traffic, ran out of power and blocked key streets, worsening a gridlock that trapped municipal shuttles and disrupted thousands of journeys. The move marks a notable shift for Lurie, who had previously championed San Francisco as a testing ground for emerging technology, and signals growing pressure on autonomous vehicle firms to prove they can cope with major disruptions, not just everyday driving conditions.

In his letter to the state Department of Transportation, Lurie cited both the July 4 fireworks crowd of 100,000 people and a December power outage as events where dozens of Waymo vehicles became stranded and paralysed traffic. He wants manufacturers to demonstrate four "core operational capabilities", including swiftly clearing stalled vehicles from traffic lanes, adapting routes and service areas in real time, sharing live operational data with local agencies, and proving through testing that they can handle sudden surges in demand. Waymo, the largest operator with roughly 1,000 robotaxis in the Bay Area, has not yet responded to requests for comment; other firms including Zoox, Nuro and Uber's forthcoming service also hold permits to operate driverless vehicles in the region.