Federal safety regulators want Tesla to spell out precisely how it will keep riders safe when its camera-only "Robotaxis" hit Austin streets next month. In a letter publicized Monday, the National Highway Traffic Safety Administration's (NHTSA's) Office of Defects Investigation (ODI) demanded Tesla outline exhaustive technical, legal and operational details of the fully self-driving fleet Elon Musk vows to deploy in June. The inquiry folds the Robotaxi rollout into ODI's ongoing probe of four crashes that occurred when Tesla's Full Self-Driving (FSD) software encountered poor visibility — a defect investigation that covers 2.4 million vehicles nationwide.