The provincial police spokesperson, Colonel Dimakatso Nevhuhulwi, said the incident took place near the Athol Oakland offramp.
He said police were investigating a case of culpable homicide.
The prisoners were being transported from court at the time of the crash.
“It is alleged that a driver of a Ford Ranger bakkie lost control of the vehicle amid a road rage incident with another vehicle, causing him to collide with a police vehicle transporting prisoners from court.
“The police bakkie had eight male prisoners, two female prisoners, and the driver (a police officer),” Nevhuhulwi said.
At the scene, three male prisoners, a female prisoner, and the driver of the SAPS vehicle were declared dead at the scene.
The other passengers of the SAPS vehicles (prisoners) and the driver of the Ford Ranger were rushed to hospital for medical treatment for injuries they sustained.
“A case of culpable homicide is opened for further investigation,” Nevhuhulwi added.