The National Highway Traffic Safety Administration (NHTSA) is investigating Tesla's Full Self-Driving (FSD) software after several incidents, including a fatal crash, raised concerns about its safety and the company's portrayal of the technology as fully autonomous. The NHTSA's scrutiny follows social media posts by Tesla and Elon Musk suggesting that FSD can operate without driver attention, potentially misleading the public. The investigation could lead to stricter regulations, significant changes to the software, and impact Tesla's market position and the broader autonomous vehicle industry.