ARLEE — The driver of a pickup truck swerved in front of a passenger bus Tuesday, causing a crash that sent both vehicles off a highway north of Missoula and injured four people, officials and bus passengers said.

The pickup driver was the most seriously hurt in the wreck on U.S. 93 north near Arlee, but three trained combat lifesavers who were on the bus gave him emergency medical attention.

All 17 passengers on the Rimrock Stages bus were then taken to Missoula hospitals for observation. Only three appeared to have moderate to severe injuries, Arlee Fire Chief Ken Light said.

The crash was reported shortly before 9 a.m. Passengers said the pickup swerved into the path of the bus.

“We were coming down the road and he (the pickup driver) swirled around in front of us, then he swerved right in front of us,” said passenger Chris Clark, 35, of Idaho.

Clark said he and two other combat lifesavers immediately went to the aid of the pickup driver, who they said suffered two broken legs and was trapped in his damaged vehicle.

The men broke out a window then took off the door to provide emergency aid to the driver.

“At first, he was coherent,” said Corey Anderson, another combat lifesaver. “Then he started going into shock. But he was in excellent condition for the situation.”

A third trained lifesaver — Michael Benoit, 42, of Kalispell — was on the bus with his mother and nephew from Oklahoma. He said his mother suffered a broken nose in the crash.

Officials with Rimrock Stages did not immediately return a phone call seeking comment.

Earlier this year, a Rimrock Stages Inc. passenger bus was involved in a crash on icy Interstate 90 in western Montana. Two people were killed and 34 were injured in the January crash near Clinton, west of Missoula.