The 21-year-old driver of a pantech that crashed into the rear of a B-double truck at Morisset on Friday afternoon is fighting for life.
The M1 northbound on-ramp near Mandalong Road was closed for several hours on Friday, November 15, as police and emergency services rushed to the scene just after 1pm.
The injured driver was trapped in the vehicle and had suffered severe injuries to his legs.
First responders freed him from the wreckage as paramedics assessed his condition as critical and unstable.
He was taken to John Hunter Hospital, where he was in intensive care.
A hospital spokesperson said on Sunday that the patient "remains in a critical condition".
The driver of the unladen B-double, a 31-year-old man, was uninjured and was taken to Wyong on Friday night for mandatory testing.
Police have yet to indicate if charges would follow the incident.
Northbound traffic was banked up for over 13 kilometres throughout Friday afternoon as tow trucks arrived just after 4pm to clear the way. Diversions were put in place as drivers were urged to avoid the area. The northbound on-ramp was closed into the evening.
The road eventually re-opened around 7pm.
Police are understood to be continuing their inquiries.