A car crash on the Trans-Canada Highway over Labour Day long weekend sent two people to the hospital in critical condition.

Canmore RCMP responded to reports of a multi-vehicle collision at 1:30 p.m. on Sunday. Police said a car travelling east on the Trans-Canada Highway near Highway 1A went through the road’s centre meridian, drove into westbound traffic and caused three other cars to collide.

There were 14 people, in total, inside the four cars involved in Sunday’s crash, police said, and two were taken to a hospital in Calgary in critical condition.

The driver of the car that crossed into oncoming traffic was also taken to hospital and treated on Sunday, before he was released and taken into RCMP custody. Police said charges are pending against the man, who is a Calgary resident, allegedly for impaired driving causing injuries as a result of the collision.

Police said an investigation into the crash is ongoing, although they believe impaired driving was a significant factor.

Cpl. Troy Savinkoff, a public information officer with Alberta RCMP, said other people involved in the collision were injured, but he could not confirm the severity of their injuries.

The crash significantly disrupted traffic on Sunday, especially on a long weekend on a major artery between Alberta and British Columbia, Savinkoff said. The highway was mostly opened back up soon after roughly 6:10 p.m., he said.