One man critically injured, transported to hospital, after his car crashes into a guardrail on Loop 303 near Surprise.

A man was in extremely critical condition after he was impaled by a guard rail that almost completely severed a leg early Wednesday morning, said an Arizona Department of Public Safety officer.

Police said it appeared the man fell asleep at the wheel of a truck he was driving about 2 a.m. on the Loop 303 at Grand Avenue when it ran into the guard rail. Impairment was not considered a factor, police said.

Police said the man suffered an extreme loss of blood, but had propped himself up in a standing position when the Surprise Police Department and Maricopa County Sheriff's Office first arrived on the scene.

He said the man, who was not identified, was talking with officers until he was placed on a body board, when he lost consciousness. He was flown to a nearby hospital for treatment.

There were no skid marks or other evidence to suggest the man was involved in a collision beforehand, but the investigation was continuing.

Yeager said the guardrail pierced the driver's side window and through the driver's seat, pushing the man into the back of the truck.

The truck contained "hundreds" of newspapers, but the owner of the truck said the man was considerably south of his newspaper route.

The Loop 303 was closed in both directions between U.S. Highway 60/Grand Avenue and El Mirage Road.