The accident happened around 8 a.m. in the 7600 block of West Hollywood Boulevard. The semi truck was parked when it apparently lost its brakes and rolled out into oncoming traffic. It collided with a passenger bus carrying about 27 people going westbound down the street. The semi sent the bus crashing into a 1998 silver BMW sedan, injuring a woman and her passenger, a 10-year-old girl.
Los Angeles Fire Department crews had to extricate the woman from the vehicle. She was transported to a local hospital in serious condition. The girl was taken to Children's Hospital and was listed in fair condition.
The 27 bus passengers were also treated at the scene and 15 were eventually taken to the hospital with unknown injuries.
One of the bus passengers described the moment of the accident.
"I was in the middle and I stood up and I just see everyone fall off their seats," said Jose Castellanos. "Everyone was falling. I was the only one standing up holding on to the rail. There was screaming and I just hear a pop and all the windows just...I don't know. It was scary."
Police have closed off Hollywood Boulevard between Curson and Fairfax avenues and asked drivers to stay out of the area, which was expected to be closed for a few hours for an investigation.