Waymo Recalls Nearly 4,000 Driverless Cars After One Drives Into Flood

Waymo, the self-driving car company owned by Google's parent company Alphabet, recalled 3,791 of its robotaxis after one of them drove onto a flooded road during heavy rain in San Antonio. The car was empty at the time. Waymo reported the problem to the National Highway Traffic Safety Administration (NHTSA) on May 1, and the agency formally acknowledged it on May 11.

The problem happened when severe weather caused streets to flood in San Antonio. A Waymo robotaxi should have avoided the flooded road, but a software bug let it drive onto the water anyway, even though the speed limit there was 40 mph. The exact details of what went wrong in the software have not been made public.

How Waymo Fixed It

Waymo sent a software update to all 3,791 affected cars to fix the problem. These cars operate in Phoenix, San Francisco, and Los Angeles for paying customers, plus other cities where Waymo is still testing its technology.

The recall was voluntary, meaning Waymo chose to report and fix it. The company was able to push the fix to all cars instantly through the internet, which is one advantage of driverless cars over regular vehicles. Federal regulators reviewed the process to make sure it was safe.

This Has Happened Before

This is not the first time Waymo has run into unexpected problems in the real world. Earlier, Waymo cars got stuck in the streets of San Francisco during a power outage that shut off traffic lights. That incident showed that driverless cars struggle when the world doesn't work the way they expect.

The flooding problem is tricky for self-driving systems. A driverless car uses cameras and lasers called lidar to understand what is around it. When water covers a road, these sensors have a hard time figuring out whether the water is shallow or dangerously deep. The system can be fooled, similar to how a human driver might misjudge a flooded street at night.

What This Means Going Forward

The fact that this problem affected Waymo's entire fleet suggests the bug was in the core software that all the cars share, not just in one type of vehicle.

For the self-driving car industry as a whole, this recall highlights a real challenge: these cars work well in sunny weather and clear conditions, but the real world includes rain, snow, floods, and heat waves. Each problem Waymo discovers and fixes makes the technology a little more robust. Over time, these fixes add up.

The broader pattern here is worth noting. Self-driving cars have improved a lot in controlled settings and good weather. But every time they encounter something unexpected—a flooded road, a power outage, a sudden rainstorm—engineers learn something new and make the software stronger. This is how the technology gets better, one real-world challenge at a time.

Waymo's decision to report and fix this problem transparently is important because the company knows that the public and regulators need to trust self-driving cars as they become more common. Other companies in the space, like Cruise, have had their own problems and had to pause service to fix them. Trust matters in this business.

As more companies deploy driverless cars across different cities and weather patterns, managing safety gets harder. That means having good systems in place to spot problems, report them, and fix them fast. This recall shows that Waymo has those systems in place, at least for updates that can be sent over the internet.

Looking ahead, incidents like this one will probably shape how regulators set rules for self-driving cars, especially around how well they need to handle bad weather. Each setback is also a step forward—finding a problem and fixing it is how the technology becomes reliable enough for the roads we actually drive on.