U.S. highway safety regulators will investigate a fatal Tesla Model S crash that authorities believe may be the first involving a car steered by the automaker’s Autopilot self-driving technology.

Joshua Brown, 40, was killed May 7 in Williston, Florida, Reuters quotes Florida Highway Patrol, when his Model S struck the side of a tractor-trailer turning left in front of him at an intersection.

In a release June 30, Tesla Motors said that apparently “neither Autopilot nor the driver noticed the white side of the tractor trailer against a brightly lit sky, so the brake was not applied.” Authorities now say Brown may also have been watching a film while letting the car drive.

The National Highway Traffic Safety Administration said the crash “calls for an examination of the design and performance of any driving aids in use at the time of the crash,” and noted it had opened a preliminary investigation, which could eventually lead to a recall.

Tesla Motors launched the semi-autonomous Autopilot feature last October, with the caveat that it was in “beta mode” testing and that fully-hands-off operation was not suggested. In January, after owners began posting videos to YouTube of themselves testing the limits of the feature, it added certain restrictions to Autopilot’s use.

Brown was apparently one of these enthusiastic Model S owners, and had posted to YouTube several videos of his car’s Autopilot in use; in one, Brown showed how the car “saved” itself from a collision with a truck that had cut him off.

The NHTSA say that during the collision that kill him, Brown’s Model S “went underneath the trailer of a truck that had turned left in front of the car,” Reuters reports.

“The Tesla’s windshield hit the bottom of the trailer as it passed underneath, and the car kept going, leaving the road, striking a fence, crossing a field, passing through another fence and finally hitting a utility pole about 100 feet south of the road.”