RCMP say an 82-year-old man, a 79-year-old woman and a 14-year-old boy were in a Chevrolet Malibu that crossed into oncoming traffic and hit a car before slamming head-on into a commercial truck.
Const. Kris Clark says everyone in the Malibu died at the scene on Tuesday afternoon.
Clark says the truck driver and the two occupants of the other car suffered serious but non-life threatening injuries and were transported to hospital.
The highway remained closed for several hours and police are continuing their investigation.
They're asking anyone who saw the crash to contact them.