One person was killed and two were seriously injured in a pair of unrelated traffic accidents in the 5 o'clock hour Sunday morning in Cobb County.

An unidentified man died after his sport utility vehicle veered off Shallowford Road and tumbled down a storm ditch just east of May Breeze Road in Marietta. The vehicle was ablaze when authorities arrived on the scene.

Officers were already dealing with another accident involving an SUV that rolled over repeatedly. Police did not know what caused the car to lose control as it crossed the shoulder of northbound I-75 at Chastain Road in Kennesaw.

Nine people were in the vehicle, and five were thrown from the SUV as it rolled, Cobb County Police Department spokesman Cassie Reece said.

Two of the injured were taken to area hospitals in critical condition, Reece said. Their identities were not disclosed,

— CHRISTIAN BOONE