A fatal pedestrian crash in DeKalb County shut down the northbound lanes of I-85 for more than two hours Tuesday morning.

According to police, a 19-year-old woman was involved in a single-vehicle crash near the Clairmont Road exit sometime before 3:45 a.m.

“It’s unclear why, but she exited her vehicle on foot and went into the northbound lanes of the interstate where she was struck by a vehicle,” DeKalb police spokeswoman Michaela Vincent said.

The woman, whose name was not released, was pronounced dead at the scene.

Authorities shut down all northbound lanes, including the HOV lane, during the investigation. Drivers were diverted off the interstate at the Clairmont Road exit, prompting heavy delays ahead of the morning commute.

Officials reopened two lanes of the interstate just before 6 a.m., and the remaining lanes were reopened a short time later, according to the WSB 24-hour Traffic Center.

The fatal crash remains under investigation.