About a dozen pedestrians are safe and unhurt after a motorist used his SUV to prevent a speeding teenage driver from slamming into them as he fled officers in downtown Montreal Tuesday, police say.

The incident began at around 12:30 p.m., when police tried to pull over a vehicle on René-Lévesque Boulevard near Berri Street, according to Montreal police spokesperson Const. Caroline Chèvrefils.

The 19-year-old driver did not yield to police and instead sped west before making a U-turn and driving in the opposite direction.

The driver then stopped just long enough for officers to get out of their patrol car before he sped off again, Chèvrefils said.

With police once again in pursuit, the vehicle approached the busy intersection of St-Denis Street. That's when another driver intervened.

"A driver who was in his Mercedes SUV was stopped at the red light at St-Denis Street and saw that the runaway car was coming toward him very fast," Chèvrefils said.

"At the same time, he saw that pedestrians were crossing the street. To protect the pedestrians, the driver of the Mercedes placed his car at an angle."

The car driven by the fleeing suspect slammed into the SUV, causing a multi-car crash that left only the suspect injured.

The SUV was sent crashing into a taxi before coming to a complete stop, heavily damaged.

The SUV, used to block a fleeing car, was heavily damaged in the collision and came to rest against a Montreal taxi on Tuesday. (Simon-Marc Charron/Radio-Canada)

The suspect was taken to hospital. Chèvrefils said he was arrested on suspicion of driving while intoxicated and when he is released from hospital, he will be taken to a detention centre for questioning.