Five other people were hurt when a Toyota Prius crossed the center line on Highway 50 near Placerville around Saturday night and struck a Toyota Sienna minivan "broadside," said California Highway Patrol spokesman Officer John Frizzell.
Three people in the Prius - a 39-year-old man driving the car, a woman and a child - were killed in the crash, Frizzell said. Another child in the car suffered moderate injuries. Three of the dead lived in the San Francisco Bay area.
Of the five people in the minivan, a 4-year-old girl was killed, Frizzell said. The four others - the 35-year-old female driver, a 51-year-old man and two 1-year-olds suffered minor to moderate injuries. No names were released.
"We don't know what caused the Prius to cross into oncoming traffic," Frizzell said Sunday. "There's an infinite number of possibilities."
Investigators have pulled computers from both vehicles that would indicate how fast they were going at the time of the crash, but collecting that information would probably take days, Frizzell said.
The highway where the crash took place is just outside of Placerville, about 45 miles east of Sacramento. The highway has two lanes, with minor to moderate curves, and with a speed limit of 65 miles per hour, Frizzell said.