WHISKEY BAY - An out-of-town trucker was killed when he careened off the I-10 Basin Bridge Monday morning.

State Police said John Cloninger, 50, of Pearl, MS, died in the wreck at the Whiskey Bay exit on I-10 in Iberville Parish.  The crash happened around 7:30 a.m.

"Cloninger was unrestrained at the time of the crash and sustained fatal injuries," troopers said.

Investigators said for reasons still unclear, Cloninger drove off the westbound travel lanes and crashed into the railing of the bridge.  The truck then fell off the bridge deck to the ground underneath. 

It appeared Cloninger crashed through the impact attenuator - a crash cushion where railings from the main highway and exit ramps meet.  Traffic camera video recorded after the crash showed a break in the railing area and the cushions missing - likely taken out as the truck drove through the safety feature and tumbled to the ground below.

Early-on, the Iberville Parish Sheriff's Office said the driver of the tractor trailer may have fallen asleep behind the wheel and accidentally driven off the bridge.  State Police did not elaborate when troopers issued their crash report later Monday.