Federal auto regulators have escalated their investigation into Tesla after several of its cars crashed while using its self-driving feature. The National Highway Traffic Safety Administration (NHTSA) is investigating nine crashes where the car's software failed to alert drivers to take control in fog or other poor conditions. This could lead to a recall of 3.2 million Tesla vehicles. The increased scrutiny comes as Tesla CEO Elon Musk prepares to launch a new model with no steering wheel or pedals. The company is also facing other regulatory probes over its FSD-equipped cars running red lights and door handles that reportedly fail to work in crashes.