Dallas County Sheriff's Department spokesman Raul Reyna said they are still investigating what caused the wreck early Monday morning. He said two adults, including a pregnant woman, and two children died in the vehicle that became entangled with the tractor-trailer. He says the driver of the tractor-trailer was unharmed.
Reyna says that when the vehicles became entangled, the gas tanks on the tractor-trailer ruptured, causing the large fire. Burning lumber fell from the overpass onto the ground below.
The accident happened on the bridge from westbound Interstate 20 to southbound Interstate 35.