The U.S. National Highway Traffic Safety Administration (NHTSA) said it has identified at least 80 instances in which Tesla’s Full Self-Driving (Supervised) software may have violated traffic laws by running red lights or crossing into incorrect lanes, according to a new letter sent to the automaker this week.
The agency said the total includes 62 complaints submitted by Tesla drivers, 14 self-reports from Tesla and four media accounts. The latest figure marks an increase from about 50 cases cited in October, when NHTSA first disclosed it was examining the behavior.
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NHTSA’s Office of Defects Investigation (ODI) said it is assessing whether Tesla’s driver-assistance system can “accurately detect and appropriately respond to traffic signals, signs and lane markings,” and whether the system provides adequate warnings to drivers. Tesla has until Jan. 19, 2026, to respond to the agency’s latest information requests.
The growing number of reports is notable because a portion of the original violations cited in October were linked to a single intersection in Joppa, Maryland. At the time, Tesla told regulators it had already “taken action to address the issue at this intersection.” NHTSA did not disclose where the newly reported incidents occurred, while Tesla’s own submissions to the agency remain heavily redacted.
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The letter was sent in the same week that Tesla Chief Executive Elon Musk said in a post on X that the latest version of Full Self-Driving would allow drivers to text while using the software — a practice that is illegal in nearly all U.S. states. NHTSA has not commented publicly on Musk’s statement.
As part of the discovery phase of the investigation, regulators are seeking detailed data on how many Tesla vehicles are equipped with Full Self-Driving, how frequently the system is used, and any related customer complaints, including those tied to lawsuits, arbitration proceedings or fleet operators.
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This marks the second active federal investigation into Tesla’s Full Self-Driving system. In October 2024, NHTSA opened a separate probe examining how the software performs in low-visibility conditions such as fog or intense sunlight.