Waymo Robotaxi Reportedly Entered Flooded San Antonio Roadway and Was Swept Into Waterway

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.

Risk classification

• Primary risk domain: 7 AI system safety, failures, & limitations
• Primary risk subdomain: 7.3 Lack of capability or robustness

The autonomous vehicle failed to perform reliably under extreme weather conditions, specifically failing to stop when encountering a flooded roadway.

Causal factors

• Entity: AI
• Intent: Unintentional
• Timing: Post-deployment

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.

EU AI Act risk tier

• Risk tier: 2 High Risk

High Risk: The report describes an autonomous driving system operating in public traffic, which is a safety-critical application in critical transport infrastructure.

AI system and alleged parties

• AI system: Waymo automated driving system fifth and sixth generation (Waymo)
• AI purpose: Autonomous Driving; Navigation Assistant
• Behaviour type: Autonomous
• Alleged developer: Waymo, Automated driving system developers
• Alleged deployer: Waymo, Robotaxi operators, Automated driving system deployers
• Alleged harmed parties: Waymo, Road users

Harm severity

Severity ratings are based on this scale.

Highest direct severity in any category: Minor. Severity is scored from Negligible to Catastrophic in each harm category, for harm the reports describe as caused directly or indirectly by the AI system.

• Physical: direct Negligible, indirect Negligible
• Infrastructure: direct Negligible, indirect Negligible
• Property: direct Minor, indirect Negligible
• Financial: direct Negligible, indirect Negligible
• Environmental: direct Negligible, indirect Negligible
• Malicious content: direct Negligible, indirect Negligible
• Differential treatment: direct Negligible, indirect Negligible
• Civil rights: direct Negligible, indirect Negligible
• Democracy: direct Negligible, indirect Negligible
• Privacy: direct Negligible, indirect Negligible
• Psychological: direct Negligible, indirect Negligible
• Epistemic: direct Negligible, indirect Negligible
• Child sexual exploitation and abuse: direct Negligible, indirect Negligible

Property

Reported: Yes, the report explicitly describes property damage to the Waymo vehicle itself.

Directly caused: One unoccupied Waymo autonomous vehicle was swept into Salado Creek and lost or damaged.

People affected

• Occurrences reported: 1

Potential causes

Management

• Inadequate Risk Assessment: Management did not fully address the risks of flooding on high-speed roadways.

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.

Information quality

• Classification confidence: High
• Reason for confidence: 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.

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.

• Overall national security impact: Minor
• Scope: Single nation
• Primary target: United States
• Alleged perpetrator: Unknown

Threat characteristics

• Imminence: Long-term. The immediate physical threat is resolved via voluntary recall and service suspension, leaving only long-term strategic safety monitoring.
• Autonomy: Full autonomy. The Waymo vehicle was operating with full autonomy, navigating public roads and making driving decisions without a human driver present.
• Novelty: Established threat. Autonomous vehicle navigation failures in adverse weather conditions are an established threat and safety concern within the industry.

Impact by dimension

• Physical security: Minor. Software failure caused an autonomous vehicle to enter floodwaters, leading to a voluntary recall of 3,791 vehicles and service suspensions. While no injuries occurred, it highlights minor physical safety vulnerabilities in autonomous transport systems under extreme weather.
• Information security: Negligible. No information warfare, disinformation, or intelligence compromise was associated with this commercial autonomous vehicle software failure.
• Sovereignty: Negligible. The incident was a localized commercial software failure with no implications for state authority, elections, or core government functions.
• Economic security: Minor. Waymo faced financial and operational impacts, including recalling nearly 3,800 vehicles and suspending services. This represents a minor, localized economic and technological setback manageable within standard commercial limits.
• Societal stability: Negligible. The incident did not involve mass surveillance, civil liberties violations, or threats to social cohesion.