The incident happened Wednesday night on Highway 290 near Cypress Rosehill. Transtar video showed heavy law enforcement activity at the scene.
Gonzalez said the driver involved called authorities and told them the woman in his vehicle had jumped out.
At the scene, deputies found a 30-year-old woman bleeding and unconscious. She was taken to the hospital via Life Flight, where she was pronounced dead, Gonzalez said.
The driver of the car stayed on the scene and cooperated with the investigation.
As of right now, it is unclear as to why the women jumped out of the vehicle.