An 18-year-old female remains in hospital following a single vehicle crash on the Hume Highway at Ladevale, between Gunning and Yass, on Tuesday, January 8.
The woman is in a critical, but stable condition, according to Yass Sergeant Dave Cowell.
The woman was a front seat passenger of a Rav4 travelling south on the highway, around 1.45pm on the Tuesday.
She sustained serious injuries when the car lost control and crashed into a guard rail and was airlifted to Canberra Hospital after the incident.
The 53-year-old male driver, as well as two back seat passengers, a 39-year-old woman and 14-year-old girl, were treated for lacerations but have since been released from hospital.
The crash investigation unit, emergency services and roads and maritime services attended the scene.
The incident is still under investigation, according to Sergeant Cowell.
Anyone with information about this incident is urged to contact Crime Stoppers on 1800 333 000 or https://nsw.crimestoppers.com.au.
Information is treated in strict confidence. The public is reminded not to report crime via NSW Police social media pages.