The Orange Unified School District bus was carrying 11 students when it crashed around 3:30 p.m. on Nohl Ranch Road near Walnut Canyon Road. The bus came to rest on a steep hillside and was propped up by a tree.
The CHP says at least two cameras on the bus were rolling moments before the crash. Investigators expect the video will provide crucial information about what happened.
"It's going to tell us a lot of stuff. It's going to tell us what speed he was going, if he was distracted, if someone cut him off," said CHP spokesman Florentino Olivera.
Some witnesses say the 24-year-old driver, Gerry Rupple, was going fast down the hill.
"It literally took this turn very, very fast. We had just past it. It just literally was airborne. It was out of a movie," said witness Andrea Shurtz.
The students on board were from El Rancho Charter Middle School in Anaheim Hills.
"I think we all froze up. We went up and then a lot of people went rolling around since a lot of people don't wear the seatbelts," said a boy who was on the bus.
Six students were transported to the hospital. Two remained hospitalized overnight. The driver, who regained consciousness Thursday night, was able to talk with investigators at the hospital. So far, authorities have not disclosed what he told them. Investigators are also examining the bus for possible mechanical problems.
Rupple's father, Randy, is also a bus driver with the Orange Unified School District. He says his son started driving several years ago and has been a full-time driver since 2010.
Meantime, school district officials say counselors were available Friday at El Rancho Charter Middle School for anyone in need.