An eastbound mid-size car collided with the bridge guardrail at about 10 a.m. today on U.S. Highway 2 at the Flathead River crossing in Columbia Falls.

The man driving the Ford Edge Sport passed out at the wheel due to an unknown cause and swerved hitting the guardrail, a Flathead County Sheriff said.

According to Montana Highway Patrol, the rental car drifted over into the shoulder, rotated clockwise and rested in the center turn lane.

The driver said he felt fatigue and didn't realize the road straightened so he continued to turn to the right, according to Highway Patrol.

The occupants of the vehicle were a Chicago man and woman on vacation.

The woman said the driver "blacked out."

The couple was headed to Great Falls from Kalispell. They are grateful that they had already visited Glacier National Park, the woman said, who declined to give her name.

No other vehicles were involved in the crash. No one was seriously injured.