A 55-year-old man is dead after the car he was driving slammed into another vehicle at a red light in southeast Calgary.

The collision happened just after 6 p.m. MT at the intersection of 52nd Street and 17th Avenue southeast on Thursday.

Police believe the man, who was driving alone in a Buick LeSabre, suffered a seizure and lost control of the car.

The Buick struck a pickup truck which in turn collided with another vehicle stopped at the intersection. Nobody in those vehicles suffered injuries.

The medical examiner will determine whether the man died from a pre-existing medical condition or as a result of the crash.