Four people died and another person was injured in a crash near Clinton in Custer County, the Oklahoma Highway Patrol said.
The time and date of the crash is under investigation, troopers said.
The single-vehicle crash happened on Interstate 40 about five miles west of Clinton.
Aime Tarango, 27, of Oklahoma City, Marleen Moncada, 36, of Oklahoma City, and two children, a 7-year-old girl and a 3-year-old boy, died at the scene, troopers said.
The vehicle was driving eastbound on I-40 and departed the roadway to the right in a gradual manner, striking concrete drainage ditch. The vehicle continued over the bridge embankment, became airborne and hit the bridge's concrete retaining wall. The vehicle rolled and landed upside down.
The two adults in the vehicle were ejected from the car.
One 16-year-old boy survived the crash and is receiving treatment at OU Medical Center.