Waymo is recalling 3,791 robotaxis in the United States after federal regulators identified a software flaw that could send the vehicles into flooded roads at higher speeds, the National Highway Traffic Safety Administration said on Tuesday.
The recall covers vehicles running both the fifth- and sixth-generation Waymo Driver, the Alphabet unit’s automated driving system.
The NHTSA said Waymo has tightened its weather-related operational limits and refreshed its maps as an interim measure while engineers work on a permanent software fix. A full remedy is still under development.
The recall traces to an incident on 20 April in San Antonio, when an unoccupied Waymo encountered what the company’s NHTSA filing called an “untraversable flooded section of a roadway” and proceeded into the standing water at reduced speed rather than rerouting. No one was hurt. Waymo filed the voluntary recall ten days later, on 30 April.
A Waymo spokesperson said the company had “identified an area of improvement regarding untraversable flooded lanes specific to higher-speed roadways” and had filed the recall in response.
The company added that it was implementing additional safeguards, refining its extreme-weather operations during intense rain, and limiting access to areas where flash flooding might occur.
The recall is small in absolute terms, but the filing is unusually revealing. By enumerating every affected vehicle, Waymo has effectively published the size of its US fleet for the first time. The 3,791 figure spans deployments in Phoenix, San Francisco, Los Angeles, Austin, San Antonio, and Atlanta.
The company had only confirmed crossing the 2,000-vehicle threshold in September 2025, which means the fleet has grown by close to 90% in roughly eight months.
That makes Waymo, by some distance, the largest commercial autonomous ride-hailing operation in the world. It also means each edge-case failure now carries proportionally more reputational and regulatory weight. The flood recall is the second software recall Waymo has filed inside six months.
In December, the company recalled more than 3,000 vehicles to address a separate software issue that had caused robotaxis to drive past stopped school buses with their warning lights flashing.
Waymo also remains under a preliminary NHTSA investigation over a January incident in which one of its driverless vehicles struck a child near Grant Elementary School in Santa Monica during morning drop-off hours. The child sustained minor injuries.
The agency’s Office of Defects Investigation is examining whether the system exercised appropriate caution given its proximity to the school, the presence of a crossing guard, and double-parked vehicles in the area.
The National Transportation Safety Board has opened a parallel inquiry into reports of Waymo vehicles passing stopped school buses across Austin and Atlanta.
The 3,791 figure also lands against the backdrop of a wider regulatory squeeze on the autonomous-vehicle sector.
The NHTSA opened an investigation last week into Uber’s Avride partner after 16 crashes in four months in Dallas, language that for once read more bluntly than the industry is used to: “excessive assertiveness and insufficient capability.”
In China, a system malfunction in April left more than 100 Baidu Apollo Go robotaxis frozen mid-traffic in Wuhan. The shape of the problem is becoming clearer: autonomous fleets fail differently, and at a scale that existing recall frameworks were not designed for.
Waymo continues to argue, supported by its own data, that the Waymo Driver is safer per mile than human drivers in the cities where it operates. Tuesday’s recall does not contradict that.
What it does, in publishing a precise count of the fleet, is sharpen the question of how regulators should respond as commercial autonomous operations move past the threshold where edge cases stop being statistical curiosities.
