A Calgary man is in critical condition after he tried to stop a man from fleeing the scene of a collision and wound up being dragged by his arm and sandwiched between a building and a van.

At about 3:30 a.m. MT on Saturday a Dodge minivan collided with a Mitsubishi sedan at the intersection of Eighth Avenue and Eighth Street S.W.

When the driver of the Dodge fled, the man driving the Mitsubishi followed him down Eighth Avenue, confronting him as they stopped at a traffic light on Sixth Avenue.

As the Mitsubishi driver reached into the minivan to try to stop the man from leaving, the driver sped north on Sixth Street with the other man hanging out of the driver side window.

Witnesses said the minivan tried to swerve around a truck near Seventh Avenue before veering onto the west sidewalk.

The minivan crashed into a restaurant just south of Sixth Avenue, slamming the man who was hanging out of the window between the van and the wall of the building, police said.

The 28-year-old driver of the Mitsubishi suffered critical life-threatening injuries.

The 43-year-old driver of the Dodge minivan was taken into police custody.

"While the Calgary Police Service recognizes the heat of the moment in this circumstance, we would like to take this opportunity to remind people to always be safe," police said.

Anyone who saw either collision is asked to contact police.