U.S. regulators have expanded a probe into Tesla's Full Self-Drive software into its performance in low-visibility conditions due to concerns about its performance. Regulators are concerned that the system fails to adequately detect and warn drivers about degraded visibility from glare, fog, or dust. The expanded probe now includes a total of 13 crashes, one of which resulted in a fatality. The probe, initially launched in October 2024, has now been expanded from a preliminary evaluation to an engineering analysis, which allows NHTSA to expand the parameters of the probe to include more cars and potential incidents. The expansion of this probe, which covers an estimated 3.2 million cars and 6 more potentially related accidents, is expected to allow regulators to gather further information on Tesla's updated visibility degradation detection system.