LOUISVILLE, Ky. (WDRB) -- A Louisville man was seriously injured after authorities say he was in a serious accident in Shelby County Monday afternoon.

According to Maj. Jason Rice of the Shelby County Sheriff's Office, the wreck occurred on Mt. Eden Road, near Tatum Road, just four miles south of Shelbyville, at approximately 3:30 p.m. Monday.

Rice said the victim was driving a Ford Explorer northbound on Mt. Eden Road when he reached a curve and -- for an unknown reason -- crossed over the centerline.

At that point, Rice said, the Explorer sideswiped another vehicle, then smashed into a second vehicle head-on in the southbound lane.

The victim -- who was in the car by himself -- suffered life-threatening injuries and was taken by ambulance to University Hospital. As of Monday night, Rice said, the man was in critical condition with severe internal injuries.

A total of four people were in the other vehicles. Rice said their injuries were minor.

A preliminary investigation does not indicate that drugs or alcohol were involved.

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