Lindsay Lohan's alleged speeding is being cited as the cause of her recent car crash.

The actress plowed into the back of an 18-wheeler truck earlier this month while driving along the Pacific Coast Highway in Los Angeles.

RadarOnline reports that the investigation into the cause is coming to an end and the contributing factor is said to be the starlet going too fast.

"The investigation is almost complete, and Lindsay was speeding in the moments before the accident," a source claimed.

"She was probably going 10 miles over the posted speed limit, which would have been around 50 miles per hour. There were no skid marks, which indicate that Lindsay was indeed speeding and didn't have time to even hit the brakes before she crashed into the truck.

"Lindsay is lucky to be alive, and that no one else got seriously injured."

Contrary to reports that a bottle containing alcohol was found in the trunk of Lindsay's rental Porsche, Sergeant Richard Lewis told the site said that the container was retrieved from the side of the road and it "doesn't mean it came from the car."