Early Wednesday, just as the morning rush hour was getting underway, three separate brush fires broke out along I-85 in Gwinnett County.
Southbound lanes before Hamilton Mill Road were closed. Traffic delays lasted for hours.
While delays have long cleared, authorities are not any closer to determining what caused the fires.
Firefighters were dispatched to the fire area between Spout Springs and Old Flowery Branch roads just before 5:40 a.m., Gwinnett fire Capt. Tommy Rutledge said in a statement.
Georgia Forestry officials were called to the scene to cut a fire break around the area with a tractor.
Firefighters were able to keep the fire from spreading to a nearby residential area, Rutledge said.
No injuries were reported and southbound I-85 reopened just before 8:45 a.m., Gwinnett police said.