Federal safety regulators are taking a much closer look at Tesla’s Full Self-Driving (FSD) system. The National Highway Traffic Safety Administration (NHTSA) announced on March 18, 2026, that it is upgrading its current investigation into an Engineering Analysis.
This move affects an estimated 3.2 million vehicles, covering nearly every Tesla model produced over the last decade, including the Model S, X, 3, Y, and Cybertruck.
The Office of Defects Investigation (ODI) is specifically concerned with how FSD handles “reduced roadway visibility.” This includes conditions like intense sun glare, fog, or airborne dust that can naturally impair cameras. According to the investigation documents, the system may fail to detect when its own vision is degraded and might not warn the driver with enough time to take over.
This investigation follows a series of nine incidents where Tesla vehicles using FSD were involved in crashes during low-visibility conditions. These incidents resulted in two injuries and one tragic fatality. In several of these cases, the FSD system reportedly lost track of or never even detected the vehicle directly in front of it.
Regulators are focusing on Tesla’s “Vision” approach, which relies entirely on cameras rather than radar. While Tesla transitioned to this camera-only system in 2021, the NHTSA is questioning if the software updates designed to detect camera degradation are actually doing their job. Tesla’s own analysis suggested that a newer software update might have affected three of the nine crashes identified by investigators, but it remains unclear when that update was sent to the fleet.
The NHTSA also noted that Tesla faces some internal data limitations that might have led to the under-reporting of similar crashes. By upgrading this to an Engineering Analysis, the government can now demand more detailed information from Tesla regarding the timing and capability of their safety updates.
