US regulators have granted a five-week extension for Tesla to respond to allegations that its vehicles have broken traffic laws while operating in what the electric automaker calls full self-driving mode. An investigation of Tesla's full-self driving feature was opened in October after the National Highway and Traffic Safety Administration said it had collected dozens of reports of the cars running red lights or driving on the wrong side of the road, sometimes crashing into other vehicles and causing injuries. The investigation covered 2.9 million vehicles, essentially all Teslas equipped with full self-driving technology, or FSD. Critics say the name is a misnomer that has lulled drivers into handing full control over to their cars. The federal agency responsible for auto safety said in a letter to Tesla on December 3, 2025 that it was investigating 62 complaints, up from 58 reported incidents in October. Tesla, headed by billionaire CEO Elon Musk, has argued to regulators and in .