The National Highway Traffic Safety Administration (NHTSA) confirmed it had opened a formal inquiry into the driver assistance system, fitted to an estimated 765,000 vehicles built since 2014.
It said it would look at the “technologies and methods used to monitor, assist and enforce the driver’s engagement with the dynamic driving task during Autopilot operation”. It will also examine the system’s object and event detection and where it is allowed to operate.
The investigation comes after the agency identified 11 crashes where a Tesla using Autopilot or Traffic Aware Cruise Control hit an emergency vehicle marked by flashing lights, road flares, illuminated arrow boards or cones. Seventeen people have been injured and one killed in the incidents since 2018.
Although it calls the system Autopilot, Tesla has repeatedly said that it is a driver aid, not self-driving technology.
In a series of emails to the California DMV, Tesla admitted that the tech could not offer more than level 2 “autonomy” which amounts to driver-supervised highway assistance.
Despite that, the firm has recently rolled out beta testing of its “full self-driving” function to some users in the US and the internet is awash with Tesla owners claiming their cars can “drive themselves”.
In a statement announcing the probe, the NHTSA said: “NHTSA reminds the public that no commercially available motor vehicles today are capable of driving themselves. Every available vehicle requires a human driver to be in control at all times, and all state laws hold human drivers responsible for operation of their vehicles."
The investigation covers Models S, X, 3 and Y built between 2014 and 2021 and, depending on the results could lead to a recall of the vehicles or other enforcement action.
A separate safety body in the US, the National Transport Safety Board, has previously urged the NHTSA to restrict where the Autopilot system can function and require Tesla to fit better systems to make sure the driver is paying attention.