The National Highway Transportation Safety Administration (NHTSA) today announced a probe into a fatal crash in Florida involving a Tesla Model S that was in ‘Autopilot’ mode. According to the U.S. regulatory agency the car struck a tractor trailer on a divided highway while the automated driving feature was enabled. The incident marks the first known fatality associated with an automated vehicle system.

NHTSA states that the automaker reported the incident to the agency as soon as it became away of it. The notification prompted the opening of an investigation into the matter that will closely examine the design and performance of the Autopilot system available on Tesla products in a ‘public beta’ form. The agency has not determined if there is a fault with the system at this time.

The crash occurred on May 7th in Williston, Fla., when “a tractor-trailer made a left turn in front of the Tesla at an intersection on a non-controlled access highway. The driver of the Tesla died due to injuries sustained in the crash,” NHTSA’s spokesman said via e-mail to Automotive News.

Tesla then issued a statement saying that this is the first known fatality involving Autopilot, which has logged over 130 million miles of use. The company went on to say that the conditions were such that both driver and the car’s automated crash features were impaired by the sun.

“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. “Had the Model S impacted the front or rear of the trailer, even at high speed, its advanced crash safety system would likely have prevented serious injury as it has in numerous other similar incidents.”

The automaker then claims that Autopilot “is not perfect and still requires the driver to remain alert.”

NHTSA, Tesla and Florida Highway Patrol are investigating the matter.