Major Collision Investigation Unit detectives are investigating a serious collision that occurred in Somerton this morning.
Emergency services were called to reports of the head-on collision at Cooper Street about 11.30am.
It is understood a black Lexus was travelling west when it crossed onto the wrong side of the road and collided with an eastbound red Hyundai and then a Mitsubishi truck.
The female driver of the Hyundai, a 73-year-old Greenvale woman, was taken to hospital with life-threatening injuries.
The driver of the Lexus, a 19-year-old Ivanhoe man, was taken to hospital with non-life-threatening injuries.
The driver of the truck, a 53-year-old Roxburgh Park man, was uninjured.
The exact circumstances surrounding the collision are yet to be determined and investigations remain ongoing.
Anyone who witnessed the collision, has CCTV, dashcam footage or any other information that could assist police with their enquiries is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report online at www.crimestoppersvic.com.au