Greensborough Highway Patrol members are investigating a head-on collision in Yarrambat earlier this month.
Investigators were told an orange Ford Ranger ute was travelling on Yan Yean Road when it collided head-on with a black Nissan Qashqai wagon at about 6.40am on December 10.
The driver of the Nissan – a 34-year-old Mernda woman – was taken to hospital where she remains with serious injuries.
The driver of the Ford – an 18-year-old Doreen man – was interviewed and released pending further enquiries.
Police continue to investigate the circumstances surrounding the collision.
Anyone who witnessed the incident, has dashcam/CCTV footage or information is urged to contact Crime Stoppers on 1800 333 000 or make a report online at www.crimestoppersvic.com.au.