Three people were killed and two sustained critical injuries in an accident on the N2 at the Bluewater Bay bridge in Port Elizabeth on Monday.
The Eastern Cape Department of Transport says a vehicle travelling towards the city overturned and ended up in the Swartkops River.
It says the driver of the vehicle, a Toyota double cab with 5 occupants, allegedly lost control after the trailer hit another vehicle.
The department says in a statement three adults were declared dead at the scene.
The two injured people were rushed to Livingstone Hospital in a critical condition.
Police have opened a case of culpable homicide.