Pedestrian struck on I-20 near Fairburn Road Saturday morning

A pedestrian is in critical condition after being struck while walking on Interstate 20.

It happened near Fairburn Road on the west side of metro Atlanta in the westbound lanes.

The pedestrian was taken to Grady Memorial Hospital.

Atlanta police say the pedestrian was struck by a tractor-trailer. The driver stayed at the scene after the incident and has not been charged.

Officers say they still don't know why the pedestrian was walking on the interstate.

The interstate was closed immediately following the incident but has since reopened.