A high school that recently held a drunken driving awareness campaign that included a mock memorial service prepared for a real one Friday for four seniors killed on a beach trip days before graduation.

Witnesses told troopers that the boys waved beer cans from a car window as they passed a busload of classmates. State police said the car was apparently racing another vehicle at up to 100 mph when it swerved off Interstate 15 and hit a tree.

Two buses came upon the scene moments after the crash, and the class trip was abandoned.

"Everybody recognized the car," said Viviane Macias, 18, was aboard one of the buses and was friends with one of the boys. "People started text-messaging and calling each other about what happened."

Grief counselors were at Perris High School, and a memorial service was set for Friday in the gym. Graduation was still on for Saturday.

The teens had decided to take a private car instead of riding school buses on the Wednesday trip to Mission Beach in San Diego, about 70 miles south.

Pablo Ruiz, 18, Javier Aguayo, 17, and Anthony O'Neil, 17, died at the scene. Jose Espinosa, 18, who was thrown from the car with Ruiz, died the next day at a hospital.

Forty-two opened and unopened cans were found scattered around the crash site, said Tom Kerns, a spokesman for the California Highway Patrol.

Kerns said one of the 17-year-olds was at the wheel but declined to identify him. The San Diego County medical examiner will determine whether the driver had been drinking.

Just last month, the highway patrol, Mothers Against Drunk Driving and others held a two-day program at the school in Perris, a fast-growing community in Riverside County about 70 miles southeast of Los Angeles, to warn students of the dangers of drinking and driving. Student volunteers portrayed drivers and victims of simulated deadly crashes and there was a mock memorial for the dead.

"Teens feel like they are invincible," said Jonathan Greenberg, superintendent of the Perris Union High School District. "I'm sure there will be lessons learned from this, but right now they're grieving too much."

Since the crash, students have scrawled messages on memorial banners, and a corner of campus has become a shrine with candles and flowers and photographs of the victims.

"It hurts not having them around," said 18-year-old Larry Belmontes.

Classmates remembered the four as well-liked, outgoing and fun-loving. Ruiz was on the wrestling team and had planned to join the Marines, while Aguayo was handy with cars.

Friends said O'Neil, known as "Cash," was a prankster who liked to take risks.

Students were trying to figure out how to pay tribute to them.

"Instead of throwing our caps into the air, we're thinking about roses," Macias said. "I think the guys would like that."