One person was sent to hospital early Thursday morning following a collision between a truck and a snowplow on Stoney Trail.
It happened around 12:30 a.m. near the 52nd Street Southeast interchange.
A Calgary Police Service spokesperson said it appeared the truck collided with the back of the snowplow being operated by a man in his 50s who was doing weather-related maintenance in the westbound lanes of Stoney Trail.
Police believe the driver of the truck, a man in his late teens, was also traveling westbound, when he suddenly changed lanes and struck the snowplow.
Police said the driver of the truck was taken to hospital with serious, life-threatening injuries.
The driver of the snowplow was also taken to hospital as a precaution.
Traffic along Stoney Trail was diverted for several hours.
Police continue to investigate the cause of the crash but believe alcohol and excessive speed are factors in the crash.
CPS is asking anyone who may have witnessed what happened to contact them at 403-266-1234.