The National Transportation Safety Board said Huang was on his phone playing a game while the vehicle’s autopilot system was engaged. The SUV swerved and hit a concrete barrier on the freeway in Mountain View, California.

The SUV also accelerated to 71 mph just before the crash. The car’s forward collision avoidance system didn’t alert Huang and the automatic emergency braking system didn’t engage, the National Transportation Safety Board found.

Despite the technology, the National Transportation Safety Board found Huang didn’t take control of the vehicle either by not steering or braking before impact.

The National Transportation Safety Board is not sure why the automation didn’t try to avoid the crash, looking at possible of faded lane lines and bright sunshine that affected the cameras, as well as closer-than-normal vehicle in the lane in front of the SUV.

The vehicle wasn’t the only thing found at fault. The cushion at the end of the barrier had not been fixed after a crash less than two weeks before.

The big takeaway National Transportation Safety Board issued though that a self-driving mode like Tesla’s Autopilot doesn’t mean that the car can fully be operated while the driver is doing other things.

“You can’t read a book, you can’t watch a movie or TV show, you can’t text and you can’t play video games,” National Transportation Safety Board  Chairman Robert Sumwalt said.