The investigation is part of a broader review of driver-assistance technologies developed by Tesla. Since opening a preliminary evaluation in October, NHTSA has sent the automaker an information request covering user complaints, field reports, crashes and internal assessments tied to possible violations while FSD was in use. The agency has already logged 62 complaints, in addition to reports from the media or crash reports.

Tesla says it is currently processing about 300 records a day, while also dealing with other NHTSA investigations, including delayed crash reporting and technical defects such as door handles. The automaker cites a heavy workload that could affect the quality of its responses. The case comes as Tesla's advanced autonomy systems continue to face questions over their reliability and compliance with traffic rules.