A dynamite truck exploded and killed all the seven people inside.
Passengers on the other truck only sustained injuries and were rushed to hospital. It is alleged that the driver of one trucks drove into the oncoming traffic.
Police suspect that the driver fell asleep behind the steering wheel. The accident happened a few metres away from a spot where 26 people died last month.
Motorists have pleaded with the transport department to place barricades between the lanes.
The road was closed for several hours.