Authorities did not release details of the crash, and no charges have been filed against Hulett pending an investigation.
Koontz, 19, was at UCI Medical Center in Orange on Tuesday. Koontz, a Fountain Valley resident, suffered several injuries.
A man who identified himself at the hospital as Nathan Koontz's father said his son is conscious but has suffered a head injury.
Jerry Koontz waited with his son in intensive care Tuesday afternoon at the UCI Medical Center before Nathan went in for surgery.
He's got a broken arm, a large gash on the head, both ankles are sprained, "but nothing too serious, thank God," Jerry Koontz said.
Jerry Koontz was more worried how his son would cope with girlfriend Heather Stamm's death.
"He loved her," Jerry Koontz said. "That was the love of his life. They were best friends, completed each other's sentences. They matched."
Unable to express how sorry he was for Heather's family, Jerry Koontz cried for the young woman who meant so much to his son.
Friends of Heather gathered for a memorial at 8:30 p.m. Tuesday at the intersection where she and Koontz were struck.
Several also visited the memorial throughout the day to place flowers and cards on a fence where loved ones hung a sign bearing signatures and notes from many of Heather's Huntington Beach High School classmates.
Anyone with information about the accident is asked to call Investigator Bob Barr at the Huntington Beach Police Department Traffic Bureau at (714) 536-5666.
