Still mourning the loss of their beloved woodwind instructor, American Fork High School's marching band will perform tonight at Brigham Young University's LaVell Edwards Stadium.

They'll tune their instruments, harness their grief for what's expected to be an emotional performance and summon the courage to get back on a bus similar to the one that rolled this weekend, claiming Heather Christensen's life.

"There's fear and I'm sure it will bring back flashbacks every time we get back on the bus as a band," said snare drummer Devin Vogelsberg. "But I'm proud to say every single player will be there. We're doing it for Heather. We've grieved and it's still OK to grieve. But we need to move on because we know that's what she would want."

Christensen, 33, died Saturday night after a charter bus carrying her and 46 American Fork students from a competition in Idaho rolled on Interstate 15. The bus driver had an apparent medical episode that may have caused her to black out and veer off the road. Christensen tried to take control of the bus, but fell through a window when the vehicle rolled.

Alpine School District officials have no immediate plans to rethink school travel policies or sever ties with the Provo-based charter company involved in Saturday's accident.

"We don't want to point the fingers at the charter company," said Alpine spokeswoman Rhonda Bromley. "The safety of our students is foremost. But this was a freak accident, and our hearts go out the driver and her family."

Debra Jarvis, the driver of the private charter bus in Saturday's fatal crash involving American Fork High School's marching band also works as a bus driver for Nebo School District.

Nebo district officials say the 50-year-old woman from Spanish Fork has been employed by the district for seven years, earning about $17,000.

She has a spotless driving record and no history of medical problems, said assistant superintendent Rick Nielsen. "She's a good employee."

Jarvis was just released Monday from Portneuf Medical Center in Pocatello and hasn't returned to work, though she remains employed, said Nielsen. She passed a physical a couple of months ago, but will be screened again for health problems that might preclude her from continuing to drive buses, Nielsen said.

District officials were unaware that Jarvis was also working for Lake Shore Motor Coach, the private charter company involved in Saturday's accident.

Idaho State police are still investigating the crash. But preliminary reports indicate Jarvis blacked out while transporting a bus full of American Fork High band members. The band's woodwind instructor Heather Christensen tried to take control of the wheel and was killed after the bus rolled.

The National Transportation Safety Board had planned on investigating the crash, but on Monday informed Idaho police they will not.

"But that won't effect our investigation," said Idaho State Police Capt. Eric Dayley.

Terry Williams, a spokesman for the National Transportation Safety Board, did not know why the board had changed its mind.

"We do not investigate all accidents," said Williams. "We weigh loss of life, and the amount of damage involved, and safety trends or anything of that sort."

kstewart@sltrib.com lschencker@sltrib.com