A 51-year-old Ammon resident died Thursday morning after the semi-truck he was driving rolled over on U.S. Highway 93 east of Challis, according to Idaho State Police.
William Park was pronounced dead at the scene. The crash happened around 10:37 a.m. near milepost 154, a rural stretch of highway in Custer County.
What Happened
Park was driving a 2005 Peterbilt semi-truck northbound on U.S. 93, hauling a trailer loaded with gravel, when the vehicle drifted off the right side of the road and dropped into a borrow pit. As Park steered to bring the rig back onto the highway, the tractor and trailer separated. The tractor rolled once before coming to rest upright; the trailer flipped and landed on its roof.
Investigators determined that Park was not wearing a seatbelt at the time of the crash. Idaho State Police are conducting the investigation.
Highway Safety and the Risk of Rural Roads
The stretch of U.S. 93 near Challis runs through remote, mountainous terrain where emergency response times are significantly longer than in urban areas. Fatal crashes in these corridors are a persistent concern for state transportation planners and law enforcement alike.
Seatbelt use remains one of the most effective tools for surviving serious crashes, particularly in commercial trucking, where rollovers carry an elevated risk of fatal injury. Idaho law requires seatbelt use for all vehicle occupants, including commercial drivers.
The crash is a sobering reminder of the dangers that large commercial vehicles face on rural Idaho highways, where road shoulders can be narrow and borrow pits — the drainage ditches running alongside roadbeds — leave little margin for error when a rig begins to drift.
State transportation officials have taken steps in other parts of the region to reduce roadway hazards. Earlier this year, the Idaho Transportation Department implemented turn restrictions at a dangerous Iona Road intersection in Bonneville County after a pattern of crashes prompted calls for intervention.
What Comes Next
Idaho State Police will continue their investigation into the circumstances of the crash. Officials have not indicated whether any additional factors, such as road conditions or mechanical issues, contributed to the accident. Findings from the investigation could be referenced in ongoing conversations about commercial vehicle safety standards and enforcement along Idaho’s rural highway network.
Park’s death adds to a troubling statewide tally of traffic fatalities on Idaho roads in 2026. Residents and commercial operators traveling U.S. 93 and similar rural corridors are reminded to buckle up, observe posted speed limits, and maintain awareness of road conditions, particularly when operating heavy or loaded vehicles.
Bonneville County News extends its condolences to the family and friends of William Park of Ammon.