A Model S Tesla car on autopilot crashed into a truck and killed the passenger on board, Joshua Brown. Car maker Tesla Motors informed the National Highway Traffic Safety Administration (NHTSA), which opened an investigation into the performance of self-driving mode.

The autopilot mode is still in Beta testing phase and was released to tech savvies. Brown has published several video on his YouTube channel testing the much-anticipated autonomous car.

“What we know is that the vehicle was on a divided highway with Autopilot engaged when a tractor trailer drove across the highway perpendicular to the Model S. Neither Autopilot nor the driver noticed the white side of the tractor trailer against a brightly lit sky, so the brake was not applied,” Tesla said in an official release on 30 June.

“The high ride height of the trailer combined with its positioning across the road and the extremely rare circumstances of the impact caused the Model S to pass under the trailer, with the bottom of the trailer impacting the windshield of the Model S,” the company continued, explaining that if the car had just crashed and not went under the truck, the outcome would have not been that severe.

This is not the first crash for a self-driving car, however, this is the first fatal one.

The company defended the technology, saying that it is still new and that the self-driving mode requests that the driver’s hands remain on the wheels at all times. Tests are frequently applied to ensure that the driver’s hands are on the wheels, the company added.

The autopilot technology for autonomous vehicles remains a questionable idea. The moral behavior of self-driving cars was the subject of a recent study which found that most respondents preferred a utilitarian approach; I.E  killing the driver if it would avoid killing a group of pedestrians. Respondents did not want to be in the self-driving car in that event, however.