Troopers from Louisiana State Police Troop L said the crash happened about 1 p.m. Monday two miles west of the exit.
Preliminary investigation revealed that the crash occurred as a 2009 Freightliner delivery truck was traveling east on Interstate 12 in the right lane of travel.
Ahead of the Freightliner was a 2006 Dodge Stratus disabled and parked on the right paved shoulder with its emergency flashers activated.
As the delivery truck proceeded eastbound, its driver, Louis Breaux, 37, failed to maintain control of the vehicle causing it to drift onto the paved shoulder and strike the parked Dodge Stratus.
The truck hit the right rear bumper of the Dodge with its left front fender. After impact, the Dodge Stratus rotated in a counterclockwise manner, crossing both eastbound lanes of Interstate 12 and coming to rest in the center grass median.
The truck continued forward after impact running off the paved shoulder into the grass. As the truck proceeded off road, Breaux overcorrected to the left, forcing the delivery truck to cross both eastbound lanes and run off the road for a second time on the north side of the roadway.
The driver of the Dodge Stratus, Rachel Anglin, 22 of Mobile, Ala., and a 2-year-old boy in the left rear seat were transported to St. Tammany Parish Hospital with moderate injuries.
The front seat passenger in the Dodge, Rebecca Blackwood of Duncan, Okla., 48, was transported to North Oaks Medical Center in serious condition.
The right rear passenger, 1-year-old infant Ethan Day, was killed.
Breaux was wearing a seatbelt at the time of the crash and refused medical treatment at the scene. He submitted to a breath alcohol test showing no detectable signs of alcohol in his system.
Breaux was subsequently booked into the Tangipahoa Parish Jail charged with Careless Operation of a Motor Vehicle, 3 counts of Negligent Injuring, and 1 count of Negligent Homicide.
Troopers are continuing their investigation; however, driver inattention is suspected to be the primary factor leading to the events of the crash.