A Utah County family is mourning a 17-year-old son, just one year after the accidental death of his younger brother.

Tyson Peterson died Wednesday, two days after he was struck by two vehicles while crossing a street in Pleasant Grove, police said.

A week earlier, Tyson had finished his credits at Landmark High School and graduated early, said his stepmother, Rebecca Peterson.

"He was talking about going to [Utah Valley University] and taking anatomy," Peterson said. "He wanted to do college classes."

Tyson's death is yet another blow to a family that already lost one young son; just 16 months ago, Tyson's 11-year-old brother, Jordan Peterson, was crushed when he was helping Tyson fix something under a car. The jack slipped, and Jordan died of severe head injuries.

Elda Brown, Tyson's aunt, said his parents were still recovering from Jordan's death when Tyson was hit Monday.

"I don't even think they've got their last funeral paid for," Brown said.

Tyson was crossing State Street at 300 East to reach a bus stop on Halloween morning when he was struck, police said. He was struck by a car in the inside southbound lane and thrown into the middle lane, where a small SUV ran over him.

Police said Tyson was wearing a black shirt and dark-gray pants, making it difficult for motorists to see him.

Tyson's family called both drivers to let them know of his death and to assure them that the family did not blame them.

"We understand it was just a terrible accident," Brown said. "There was absolutely nothing they could do."

Brown and Peterson said the family is taking comfort from Tyson's role as an organ donor. Doctors told them Tyson's organs could go to as many as 12 patients.

"I'm so proud of him for making that choice," Peterson said. "He's going to live on."

In life, Peterson said, Tyson "gave his heart to everybody."

"He was constantly smiling," Peterson said. His close friends from Landmark High School are devastated, Peterson said.

His girlfriend visited Wednesday night and asked to stay the night in his room to grieve by herself, Peterson said. Soon after that, another friend arrived and asked to sleep on the family's couch.

"They wanted to mourn close by," Peterson said.

Tyson liked to play sports and guitar, Brown said. His grandmother called him "Ty-Bear."

The family has opened a fund in Tyson's name at Zions Bank to help pay for medical and funeral costs.

ealberty@sltrib.com

Twitter: @erinalberty