Fawkner Highway Patrol officers are investigating a three-vehicle collision in Coburg on 9 October.
Police believe that a Toyota Hilux collided with a Toyota Corolla, travelling on the opposite side of the road, near the intersection of Bell and Gordon streets about 10pm.
The Hilux then collided with a Mitsubishi Utility.
The driver and sole occupant of the Hilux, a 28-year-old Oak Park man, was taken to hospital with life-threatening injuries where he remains in critical condition.
The driver and sole occupant of the Mitsubishi, a Sunbury woman, was taken to hospital with minor injuries.
The driver and sole occupant of the Corolla, a 35-year-old Pakenham man, was treated at the scene.
The investigation into the circumstances surrounding the incident remains ongoing.
Anyone who witnessed the incident, has CCTV, dashcam footage or any other information that could assist police is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report online at www.crimestoppersvic.com.au