The accident happened on Friday afternoon as police were on the road, clearing rocks, spokesman Synock Matobako said.
“The rocks had been thrown onto the freeway by criminals. They stand on top of the bridge, throwing rocks at passing cars. When you stop, they hijack your car,” said Matobako.
He said the driver of the Opel Astra hit a rock which was still on the road.
“He swerved and got onto oncoming traffic, hitting a Toyota Yaris.”
The driver of the Yaris, who was travelling alone, was instantly killed.
There had been four occupants in the Astra.
“Two of the occupants, including the driver died on the scene. A third person died in hospital while the fourth passenger was admitted to the Chris Hani Baragwanath Hospital. He is in a critical condition.”
Matobako warned motorists to be careful of the Golden Highway area as police had claimed that several motorists had been victims of the hijackings using the stone-throwing modus operandi.
“It is a very dangerous area. It’s a hotspot. If you stop after getting hit by a rock, you will be hijacked,” he said.