As a result of the accident, the tractor-trailer stopped in the highway and a short time later a Chevrolet Lumina crashed into the back of the tractor-trailer.
Images from Chopper11 HD showed the Chevy plowed into the back of the truck at mile marker 176 near Roxboro Road.
Officials say both occupants of the Lumina were trapped inside the car and had to be freed by Durham firefighters. They were both taken to Duke University Hospital for treatment of serious injuries.
Two occupants in the Jaguar were taken to Durham Regional Hospital for treatment of injuries that did not appear to be life-threatening. The driver of the tractor-trailer and the two occupants of the van were not injured.
All the southbound lanes of I-85 had to be closed down, so the Life-Flight helicopter could land on the interstate to take one of the injured to the hospital. Their condition is not known at this time.
Traffic on the interstate was backed up for three hours as hundreds of drivers were re-routed off of the interstate, while crews cleared the scene.
"It took us about 45 minutes to go about two miles," driver Bob Craig said.
Authorities have not charged anyone in the accident.