A medical examiner plans to use dental records to confirm the identity of the motorist whose body was found inside the car.
Authorities say the accident happened shortly after 4 p.m. Monday, just before the evening rush hour.
Cobb County police tell The Atlanta Journal-Constitution that the driver of the Buick Regal had pulled over to the right emergency shoulder on I-75.
A Highway Emergency Response Operators (H.E.R.O.) roadside assistance truck was about to stop and help. However, the Buick pulled away from the H.E.R.O. unit, went about 100 yards and then plunged down the ravine and crashed into trees.