Nine people died and 20 others were injured in the multi-vehicle pileup near the Barry Marais offramp on Monday.
The Road Traffic Management Corporation (RTMC) said preliminary information on the deadly N3 South collision suggested a truck driver made an abrupt stop on the highway, causing the tragedy.
Police have opened a case of culpable homicide and reckless driving.
RTMC spokesperson Simon Zwane said: “Investigations continue but it looks like a freight truck suddenly stopped in the middle of the road, resulting in multiple car collision. Investigators have been on the scene trying to piece together all the pieces.”
ER24’s Russel Meiring said on Monday at least eight vehicles, including trucks, were involved in the pile-up.
He said several people were found lying on the road, with others still trapped inside cars when paramedics arrived at the scene.