A county road bridge over Interstate 80 (search) collapsed Friday night after a semitrailer slammed into support beams in the middle of the roadway.

The driver of the westbound truck was pronounced dead at the scene, said Nebraska State Patrol Trooper Doug Miller. The driver's identity was not immediately known.

Miller said there was no immediate indication why the truck driver drove off the road.

A total of four semitrailers and a car were trapped under the collapsed bridge, said Gov. Mike Johanns spokesman Chris Peterson, relating witness reports from the scene called into his office in Lincoln.

However, Miller said early Saturday morning that the patrol only knew of three eastbound semitrailers that were damaged by the falling debris, and none was trapped under rubble. He also said no car was involved.

There was one other person slightly injured in the crash, and was treated and released from Sedgwick County Medical Center in Julesburg, Colo., a nursing supervisor said.

Callers to Ogallala radio state KOGA said the bridge that collapsed was used by local traffic over the interstate. It was located about three miles west of Big Springs (search), and did not have access lanes to the interstate.

Interstate traffic was being rerouted for a 10-mile span around the accident site, Peterson said.

"We're completely packed right now," said Stanley Crandell, assistant manager at the Bosselman Travel Center in Big Springs. "Just a lot of people wanting to know how to get around and keep going to Denver."

The Nebraska Department of Roads (search) ordered equipment to the scene to clear the rubble.

Peterson earlier estimated the interstate would be cleared by Saturday morning, however revised that after officials arrived on scene and saw the damage.

"The bridge fell in such a way that it won't be easily cleared," Peterson said. "It's too early to determine how early the interstate will reopen, the assessment is under way."

Reopening the interstate during the busy Memorial Day (search) weekend is important to state officials and merchants after a nearby portion of the interstate was closed during the July Fourth weekend last year.

That was caused when approaches to two interstate bridges in Ogallala (search) washed out in flash flooding. A truck driver, William B. Baucam, 46, of Dallas, N.C., died when his rig plunged off the highway soon after one of the approaches washed out.

Interstate 80, the nation's busiest highway, was closed for a week while repairs were made. However, local merchants said the closing hurt their summer tourism business with the state's largest reservoir, nearby Lake McConaughy.

Big Springs is 20 miles west of Ogallala and at the crook of the Nebraska Panhandle, or 315 miles west of Omaha.

About 10 miles west of Big Springs is the Interstate 80-Interstate 76 interchange. The latter is the main route to Denver from Nebraska.