A 43-year-old Logan, Utah, man was in critical condition Tuesday after the car he was a passenger in rolled over near Kellogg.
John R. Williams was flown by helicopter to Deaconess Medical Center in Spokane following the accident.
Williams and his 19-year-old son, also identified as John Williams, were driving west on Interstate 90 at about 12:45 p.m.
The 19-year-old was driving when his car hit a guardrail, according to the Idaho State Police.
The vehicle flipped over several times, ejecting the older Williams.
The teenager was pinned inside the wreckage. He was first taken to Shoshone Medical Center and then transported to Deaconess, where he was listed in stable condition late Tuesday.