Three California residents are dead and another is in critical condition after what has been deemed the worst accident in the history of the Sacramento light rail system.

The accident occurred last Saturday in a residential neighborhood south of downtown Sacramento. Video from cameras mounted on the train and at the rail crossing showed an SUV attempting to drive around a set of lowered crossing arms. The SUV was the hit by a train, which flipped it over and pushed it approximately 30 yards down the track.

The vehicle was being driven by a 62 year-old man. Inside the car were his 25 year-old daughter, his 22 month-old grandson and his 57 year-old wife. The driver, his daughter and his grandson were all killed in the accident. His wife was critically injured and is currently in intensive care at the University of California, Davis Medical Center.

Six train passengers also suffered personal injury in the collision.

Authorities say the driver grew impatient and decided to drive around the crossing arms. However, it is possible he might not have been aware than a light rail train was coming.

The crossing arms originally came down to allow two Union Pacific freight trains to proceed through the intersection. After those trains passed, several minutes elapsed before the light rail train arrived. All told, approximately 7 1/2 minutes passed between the time the crossing arms first came down and the time the accident occurred.

A crash of this magnitude is rare for the Sacramento light rail system. In the last five years, there has only been one other fatality.

Source: Silicon Valley Mercury News, "Calif. Rail Crash is System's Worst," Tom Verdin, Jan. 30, 2012.