RCMP responded to a crash on Highway 1, west of Parkbeg Sunday afternoon.
The crash occurred in the eastbound lanes.
In a statement issued at 3:30 p.m., police said drivers could expect a seven to eight hour delay.
As of 5 p.m. mounties said some traffic was able to get through; however, a lane restriction was still in place as they continue with their investigation.
In a tweet at 2:21 p.m., STARS Air Ambulance said they were called out to the same area for an emergency.
At 1 a.m., police said traffic flow on the highway returned to normal.
Parkbeg is 57.5 kilometers west of Moose Jaw.