Lindsay Lohan was treated in hospital after rear-ending a truck in her Porsche, trashing the car but only causing minor injuries to the perennially troubled actress, police said.

The 25-year-old spent two hours undergoing tests after the accident in which the car she was reportedly driving smashed into a 18-wheel big rig on the Pacific Coast Highway, west of Los Angeles.

A Santa Monica Police Department statement said that police "responded to a traffic collision ... involving a large dump truck and a black Porsche occupied by Lindsay Lohan and an adult male.

"A preliminary investigation revealed that both vehicles were driving northbound on Pacific Coast Highway when the Porsche struck the rear end of the dump truck. Cause of the accident is under investigation."

There was no indication that Lohan was under the influence of alcohol or drugs, it said, unlike in 2007 when she was convicted of driving under the Influence (DUI) having tested positive for booze and cocaine.

The truck driver was unhurt and not "impaired" -- under the influence of alcohol or drugs. "The occupants of the black Porsche were determined to not be impaired and were (taken) to a local hospital for treatment of minor injuries."

In March an LA judge formally ended Lohan's"Investigators are attempting to determine the driver of the black Porsche at the time of the collision," it added. Initial media reports suggested Lohan was driving the Porsche.

Pictures of the car showed its front end totally crushed, and the TMZ celebrity website said Lohan suffered bruises and bleeding in the crash. An assistant was also in the car at the time.

A publicist for Lohan said the actress was on her way to a movie set when the crash occurred, and she was taken to a hospital "as a precaution," but was released in less than two hours and was "fine."

"Everything is OK," publicist Sophie Goodale told AFP.

After leaving hospital she headed straight to the set of her latest film, a television movie about Hollywood legend Elizabeth Taylor and her stormy romance with actor Richard Burton.

The "Liz and Dick" role is a break for Lohan, who after a promising early start has become known chiefly as a hell-raising celebrity with substance abuse problems and frequent brushes with the law. probation after a long string of court appearances, but told the "The Parent Trap" and "Freaky Friday" star to "stop the nightclubbing" and behave more maturely.