Patrick Joseph Murphy, 56, jumped from the cab of his 18-wheeler as it began to jackknife.
The Phoenix truck driver was driving downhill, two miles west of Woods Canyon Lake Road when he made the escape. The truck was still driving at highway speed.
"The vehicle continued westbound, out of control, running over the driver's lower leg, amputating it below the knee," said Arizona Department of Public Safety Sgt. John Whetten. "The vehicle came to rest upright in a snow bank."
The accident occurred at 7:44 a.m. March 13 after the vehicle crossed an icy bridge on State Route 260. Murphy was airlifted to a Valley trauma center with multiple abrasions to his face, hands, arms and body as well as the amputation of his lower leg. The leg was too mangled to be reattached.
"It is believed that the driver would have been uninjured had he remained in the cab of the truck," said Whetten. The Hurley 18-wheeler was returning to Phoenix, empty, after delivering a load of newspapers.