Waymo issued a voluntary NHTSA recall of 3,800 robotaxis using 5th and 6th gen ADS to patch a software flaw letting vehicles enter flooded roadways.
Key Takeaways
Trigger incident: April 20, a Waymo AV in San Antonio drove into a flooded road and was swept into a creek, prompting an NHTSA probe.
Recall covers all US Waymo vehicles on gen-5 and gen-6 automated driving systems; fix is a software update, no hardware swap.
Waymo has added operational mitigations limiting service area during extreme weather and flash flood conditions while the patch deploys.
San Antonio service remains suspended; Waymo says it is “readying operations to resume public rides.”
Pattern of edge-case failures: school bus yielding in Austin, power-outage gridlock in SF, now flood detection across multiple cities.
Hacker News Comment Review
Core technical debate is whether standing water can be reliably detected via existing sensors (camera + LiDAR) or requires a dedicated water-depth sensor; a DARPA Grand Challenge veteran noted they added a physical water sensor in 2005 precisely for this.
Inferring water depth from vehicle dynamics (sudden deceleration, steering correction) plus machine vision is proposed as a sensor-free fallback, but commenters note false positives on shallow puddles are a real cost.
Tesla FSD is not ahead here: a recent Reddit clip showed a HW4 vehicle on FSD 14.3.2 attempting to drive into a lake, though other clips show FSD routing around standing water in some cases.
Notable Comments
@drob518: Texas-specific context – flat terrain, limestone substrate, and dedicated “low water crossing” roads make flooding far more common and harder to generalize from other markets.
@blueskies1029: flags New Orleans rollout as a stress test given endemic standing water and hidden pothole hazards beneath it.
