A man killed in a car accident may have his Tesla on autopilot when he posted social media videos of himself, police said.
The National Highway Traffic Safety Administration is investigating the crash in Fontana, 50 miles east of Los Angeles.
It is the 29th case that the federal authority has investigated in which a Tesla.
Driver Steven Michael Hendrickson, 35, died after his Tesla Model 3 hit an overturned truck at around 2:30 a.m. on May 5.
Another man tried to help the truck driver when the Tesla hit him, leaving him badly injured.
Mr. Hendrickson was a member of the Southern California branch of a Tesla club and posted photos and videos of his car on social media.
In a video on Instagram, he was sitting in the driver’s seat with no hands on the steering wheel or foot on the pedal, with the comment: “Best car pool buddy possible, even takes the boring traffic for me.”
The California Highway Patrol said their investigation so far found that the Tesla’s partially automated driving system – autopilot – was on before the crash, although they haven’t determined whether it’s a contributing factor.
They did not indicate when the videos were posted, but added that drivers need to be reminded that “driving is a complex task that requires the driver’s full attention”.
The autopilot can keep a car in its lane and at a safe distance behind the vehicles in front, but Tesla has stated that it is not fully autonomous and drivers must continue to be careful and be ready to take over driving at all times.
At least three people have died in previous US autopilot accidents.
