LITTLETON, Colo. -- "It is really common, actually," said Jake Elvig, a freshman at Heritage High about "skitching."

Skitching is skateboarding and hitching a ride on the side of a moving vehicle, students said.

The combination proved to be deadly for Johnny Nicolette, 18.

He died after a 9 a.m. accident, just a few yards away from his school, officials said.

On Friday, the Arapahoe County Coroner's Office completed the autopsy, concluding Nicolette died of "blunt trauma to the head and chest."

Friday's traditional "Senior Scram" was held on the fields at the school. Some students told 7NEWS the day they'd hoped would be nothing but good times and great memories was tempered by Nicolette's death.

"It's a damper," said junior Colin Glesner.

Some students brought more than two dozen black T-shirts with inspirational messages to school.

"I was very touched," said the mother of a Heritage senior.

Another student, Aldora Gauthier, brought 10 safety helmets, although she never met the teenage victim.

"But I came up on the accident. So, I was here. And I didn't know what else to do. I just felt it was a calling by him to get his friends to wear helmets. So all of Johnny's friends -- come here and get a helmet. And people -- donate a helmet, " Gauthier said.

Heritage seniors graduate on Tuesday. The driver of the Jeep is also a senior at the school.

7NEWS has chosen not to identify him at this time.