RCMP. Cpl. Colette Zazulak says police got a call about the driver of one of the gravel trucks moving erratically and at a high rate of speed.
She says as the person was on the phone with 911, they saw that truck collide with another gravel truck turning onto the highway from a range road.
Zazulak says the first vehicle burst into flames but passersby were able to pull out the driver, though he suffered extensive burns.
The driver of the second gravel truck was taken to hospital in Edmonton by ground ambulance.
Rocks and other debris blanketed the highway as emergency crews worked to get the drivers to safety and clean up the area.