SATSUMA -- The driver of an 18-wheeler died behind the wheel Wednesday morning causing his truck to hit a bridge rail on Interstate 12 in Livingston Parish and blocking traffic, according to a Louisiana State Police news release.

The fatal crash occurred around 2 a.m., the release says.

investigators think the driver may have suffered a fatal medical condition, the release says.

A preliminary investigation revealed the a 2005 Peterbuilt Tractor Trailer was traveling eastbound on Interstate 12, east of Satsuma, when the driver died, the release says.

The truck drifted to the left and hit a bridge rail before coming to rest and blocking the inside lane of travel, the release says.

There was no braking or steering input before the crash occurred and troopers suspect the driver was unconscious before the vehicle struck the bridge rail, the release says.

The Livingston Parish Coroner's Office pronounced the driver dead at the scene.

He was wearing a seatbelt and did not sustain injuries in the crash.

The driver's name was not released pending notification of his death to his family.