US regulators escalate Tesla FSD investigation after nine collisions
The US National Highway Traffic Safety Administration escalated its investigation into Tesla's Full Self-Driving system after nine collisions, including one fatal accident, where the system allegedly failed to detect reduced visibility from fog or glare and did not alert drivers to resume control. The investigation covers 3.2 million Tesla vehicles and could result in a recall or other enforcement actions.
What happened
The National Highway Traffic Safety Administration (NHTSA) escalated its investigation into Tesla's Full Self-Driving (FSD) system on 18 March 2026, examining nine accidents in which the autonomous driving software failed to alert drivers to resume control in low-visibility conditions such as fog or glare.
The investigation focuses on Tesla's degradation detection system, which is designed to recognize when visibility is reduced and warn drivers to take control. According to the NHTSA, available data suggests the system, both in its original form and after updates, fails to detect reduced visibility or adequately warn drivers in situations involving glare or other obstructions.
Reported impact
The investigation covers approximately 3.2 million Tesla vehicles across different models, representing nearly all vehicles sold by the company in the United States.
One of the nine accidents linked to the technology was fatal. Tesla's stock fell 3.2% to $380.30 as a result of the regulatory escalation.
Index analysis
The escalation marks a significant step that could lead to a recall or other enforcement measures if regulators discover a safety defect.
The timing coincides with Tesla's planned deployment of driverless robotaxi services in multiple US cities this year and the anticipated launch of the Cybercab, a vehicle without a steering wheel or pedals, scheduled for the following month.
Classification
Sources and evidence
This record was researched and written by the Index, based on the following original reporting.