Bartow County Emergency Management Services Public Safety Coordinator Brad Cothran said crews were called just before 6:30 a.m. to the area of the lake bridge on Interstate 75 northbound to a multiple-vehicle crash.
Bystanders and witnesses told EMS the four victims were standing outside the vehicles when a tractor-trailer struck the victims and the two cars on the bridge, Cothran said.
One individual fell from the bridge about 40 feet to the ground.
One person was transported by ambulance to Kennestone Hospital; three air ambulances took individuals to Grady Memorial Hospital, Atlanta Medical Center and Kennestone.
"We have been able to confirm that two of the patients were trapped under the tractor-trailer. Those patients were extricated by Bartow County Fire Department," Cothran said.