By Hyunjoo Jin

A Tesla vehicle that was operating on its Autopilot software crashed into a stationary truck on a highway in Pennsylvania on Friday night, police said, adding to scrutiny of the automaker's driver assistance system.

The Tesla was traveling in the middle lane when it struck the rear end of a Freightliner semi-truck that was parked in the same lane and providing traffic control for a right lane closure, the Pennsylvania State Police said on Monday.

The police said the car lost control due to being on Autopilot, adding that the 18-year-old male driver was charged with "careless driving."

No injuries were reported, according to police.

Tesla, which does not have a public relations department, did not respond to a request for comment.

U.S. regulators have been investigating a series of accidents where Tesla vehicles on Autopilot collided with parked emergency vehicles.

In February, a Tesla Model S crashed into a stationary fire truck in Walnut Creek, California, killing the car's driver and triggering an investigation by the National Highway Traffic Safety Administration.

Tesla says Autopilot enables a car to steer, accelerate and brake automatically within its lane, but those features require active driver supervision and do not make the vehicle autonomous.

(Reporting by Hyunjoo Jin; Editing by Jamie Freed)