The National Highway Traffic Safety Administration (NHTSA) opened a safety audit into approximately 1,000 Tesla Cybercabs.
The probe began one day after Tesla launched its initial commercial robotaxi service in Austin, Texas.
Investigators are examining the technical data Tesla used to self-certify that the vehicles meet federal safety standards.
NHTSA is questioning how the Cybercab complies with regulations designed for human drivers since it lacks a steering wheel, pedals, or mirrors.
The agency will determine if Tesla incorrectly decided that certain safety standards were not applicable to its autonomous vehicles.