A 21-year-old driver is still in critical condition Saturday morning after the car he was driving struck a tree and then hit a bus shelter in Montreal's Notre-Dame-de-Grâce neighbourhood Friday afternoon.

Montreal police say the single-vehicle collision happened around 1:40 p.m. on Côte Saint-Luc Road between Grand Boulevard and Kensington Avenue.

Three passengers in the Infiniti car, all 20 years old, were also critically injured and sent to hospital, but they are now in stable condition, police spokesperson Jeanne Drouin said early Friday evening.

Nobody was in the bus shelter at the time of the collision and no pedestrians were injured.

Witnesses told CTV News the car was speeding before the crash. The impact was so hard that the car's fender was found 15 feet away. The air bags were also deployed.

bus shelter

Charlie Williams lives in the area and was heading out of his building to walk his dog when he heard sounds of the crash nearby.

He told CTV News he heard several seconds of "loud braking" followed by a crashing sound and a car honking. As he went to investigate on the street, he came to a horrific scene.

"I saw a wrecked vehicle and people going towards it. My instinct was to go help as well. While going to the car door I realized a person was hanging out of the window, unconscious, bloodied and the car door was bent around him," he said.

Williams said he started to pull the man out of the car but immediately stopped in order to let a first responder handle it to prevent further injuries.

Montreal police are investigating and trying to determine whether or not speed or alcohol or drugs may have been a factor in the collision.

With files from CTV News Montreal's Rob Lurie