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A Waymo autonomous vehicle was swept into a waterway in San Antonio after failing to stop for flooded road conditions. The incident, caused by a software issue in the vehicle's automated driving system, resulted in a voluntary recall of nearly 3,800 vehicles and the temporary suspension of services in several US cities. No injuries were reported as the vehicle was unoccupied at the time.
An unoccupied Waymo robotaxi reportedly entered a flooded roadway near Salado Creek in San Antonio on April 20, 2026, and was swept into a nearby waterway. Waymo told regulators that the vehicle detected potentially untraversable floodwater but proceeded at reduced speed. No passengers were aboard and no injuries were reported. Waymo restricted operations and later recalled 3,791 fifth- and sixth-generation automated driving systems.
Domain classification, causal taxonomy, severity scores, and national security assessments were LLM-classified and may contain errors.
AI systems that fail to perform reliably or effectively under varying conditions, exposing them to errors and failures that can have significant consequences, especially in critical applications or areas that require moral reasoning.
The autonomous vehicle failed to perform reliably under extreme weather conditions, specifically failing to stop when encountering a flooded roadway.
AI system
Due to a decision or action made by an AI system
Unintentional
Due to an unexpected outcome from pursuing a goal
Post-deployment
Occurring after the AI model has been trained and deployed
The incident was caused by a software issue in the Waymo autonomous vehicle's driving system, which led to an unexpected and unintended outcome of driving into floodwaters.
An unoccupied Waymo autonomous vehicle was swept into a waterway due to a software failure during flooding, prompting a voluntary recall of 3,791 vehicles and temporary service suspensions. The incident represents a minor physical and economic security concern, highlighting robustness challenges in autonomous transport systems under extreme weather, but poses no significant national security threat.
The Waymo vehicle operates independently on public roads, making real-time driving decisions based on its sensor inputs and automated driving system without human intervention.
High Risk: The report describes an autonomous driving system operating in public traffic, which is a safety-critical application in critical transport infrastructure.
The AI system is an automated driving system designed to operate a robotaxi autonomously on public roads.
The reports provide clear, consistent details about the specific incident in San Antonio, the technical reason for the failure, and the subsequent recall and service suspensions. There is no conflicting information regarding the core event.
None
Technology
Flawed Flood Response Logic
AV slowed down instead of stopping when detecting untraversable flood water.
Inadequate Software Safeguards
System lacked robust safeguards to prevent entry into high-risk standing water.
Data Inputs
Outdated Mapping Data
Vehicle maps lacked real-time updates on localized flash flood conditions.
Missing Real-Time Weather Data
System failed to integrate live weather alerts into routing and navigation.
Process and Methods
Weak Extreme Weather Protocols
Operations failed to proactively restrict routes during intense rain events.
Management
Inadequate Risk Assessment
Management did not fully address the risks of flooding on high-speed roadways.
AI system involved
Identified by automated extraction; can differ from the alleged developers above.
No population impact data reported.
