Why Did Waymo Recall 3,800 Robotaxis? Inside the Software Failure That Sent Vehicles Into Flooded Roads

Waymo has issued a voluntary recall of nearly 3,800 of its autonomous vehicles after a software defect in its self-driving system allowed robotaxis to enter flooded roads.

The U.S. National Highway Traffic Safety Administration (NHTSA) acknowledged the recall in a letter dated May 11, noting that the software was able to recognise the hazard and slow the vehicle, but still permitted it to drive into standing water on higher speed roadways.

Waymo Recalls Nearly 3,800 Robotaxis After Software Defect

Waymo has initiated a voluntary recall of thousands of its autonomous vehicles following a software defect that allowed a driverless car to enter a flooded roadway. The NHTSA confirmed the recall, stating it affects 3,791 vehicles equipped with Waymo's 5^th and 6^th Generation Automated Driving Systems (ADS).

Under normal conditions, autonomous systems are expected to detect and avoid hazards such as flooded roads. However, in this case, the software recognised the risk and slowed the vehicle, but still allowed it to proceed into the standing water.

'Entering a flooded roadway can cause a loss of vehicle control, increasing the risk of a crash or injury,' the agency said in its recall acknowledgement.

The recall follows an incident on April 20 in San Antonio during extreme weather, when a Waymo vehicle entered a flooded lane. The company said the vehicle was unoccupied, and there were no injuries. However, the incident prompted them to review similar situations involving high speeds and flooded roads.

According to the NHTSA, a remedy is currently in development. As an interim remedy, Waymo modified the scope of vehicle operations to increase weather-related constraints and updated the vehicle maps. The company said all the affected vehicles received the interim update by 20 April 2026.

In a statement, a Waymo spokesperson said that the company has 'identified an area of improvement regarding untraversable flooded lanes specific to higher-speed roadways,' and made the decision to file a 'voluntary software recall' with the NHTSA.

The full statement reads:

'Waymo provides over half a million trips every week in some of the most challenging driving environments across the U.S., and safety is our primary priority. We have identified an area of improvement regarding untraversable flooded lanes specific to higher-speed roadways, and have made the decision to file a voluntary software recall with NHTSA related to this scenario. We are working to implement additional software safeguards and have put mitigations in place, including refining our extreme weather operations during periods of intense rain, limiting access to areas where flash flooding might occur.'

The company has previously faced complaints over its vehicles failing to yield to school buses in Austin. In December, during widespread power outages, robotaxis in San Francisco halted in traffic and caused gridlock, drawing criticism over their performance.

Additionally, the company ​is facing ⁠an investigation after a self-driving vehicle struck a child near a school last January ​in Santa Monica, California, which caused ​minor injuries.

Waymo currently operates commercial robotaxi services across 11 US markets, with broad public access in San Francisco, Austin, Los Angeles, Phoenix, and Miami. Its San Antonio service remains temporarily suspended.