A fellow student and his twin brother were in the 1994 Ford Ranger that plowed into a crowded crosswalk Wednesday and sent the students to the hospital, three of them in critical condition.
"The kids were in the crosswalk doing everything right," said Emily Shaw, principal at Hemet High School.
Nine people were hit: six female students, two male students and a 60-year-old woman whose ties to the school were not clear.
The truck's driver, 18-year-old junior Daniel Carrillo, was not under the influence of drugs or alcohol, California Highway Patrol Officer Darren Meyer said.
Authorities gave no indication of how or why he may have shot through a red light and hit the pedestrians who were headed toward the student parking lot and school football stadium.
Carrillo, in the truck with twin David and a 16-year-old friend, immediately got out to help, Meyer said.
Three of victims, all students, were in critical condition, and six more were taken to hospitals with minor injuries, CHP and county fire officials said. None of the victims' names was released.
The collision came with just two days left in the school year and on the last day of classes for graduating seniors, none of whom were among the victims.
Witnesses told the Riverside Press-Enterprise that the driver, whose truck was modified for off-road use, seemed to accelerate into the intersection, running a red light and hitting the pedestrians.
Rick Chavez said he was at the red light and saw the truck go through it just after he picked up his son.
"I saw the truck and started screaming out 'Whoa, whoa, whoa!'" Chavez said. "He plowed right into the kids. Two girls were really bad. I thought they were gone."
The CHP would decide whether to file criminal charges after a thorough investigation, including a mechanical inspection of the truck, Meyer said.
Law enforcement was reviewing video from multiple cameras around campus that recorded the accident.
School activities director Al Fernandes said his 17-year-old daughter was among those hit. He told the newspaper the girl was conscious and talking but extremely sore at Moreno Valley Regional Medical Center.
Hemet is a desert community about 80 miles southeast of Los Angeles.
