The site of a spectacular collision between three B-doubles and a pantech truck is one of the last remaining single carriageway areas of the Pacific Highway in New South Wales.
A complex recovery operation has begun to salvage the four large trucks that collided near Moorside Drive at Telegraph Point, 15 kilometres north of Port Macquarie at 2:00am on Thursday.
Roads and Maritime Services (RMS) said the salvage operation would be underway for most of the day with traffic backed-up for 6 kilometres.
The RMS confirmed the crash happened on a section of the highway where routine maintenance was being carried out.
However, it is unclear to what extent, if any, roadworks contributed to the accident.
"This section of the highway is being bypassed by the Oxley Highway to Kundabung Pacific Highway project, which is expected to be completed in coming months," an RMS spokesman said.
Dave Wright from the Transport Management Centre said it was rare for several trucks to collide in the middle of the night.
He said the initial understanding is that a couple of the trucks were stationary and another truck hit at speed.
"The trucks are jammed together so it is actually removing them from each other and then actually getting enough heavy tows," he said.
"There is actually only a couple of heavy tows in the state to move these vehicles off because some of them aren't driveable and that is the problem."
One of the drivers, a male in his 40s, was trapped in his cab for hours. He was freed about 5.40am and airlifted by the Westpac Rescue Helicopter to John Hunter Hospital in a serious condition with chest and leg injuries.
Two other drivers were taken by ambulance to Port Macquarie Hospital where they remain in a stable condition.
A school bus driver named Robert said the delays had caused him to run late for his morning run.
"I'm picking up 35 kids. We might be running a bit late but we'll get them there," Robert, who did not want his surname published, said.
"It's all good. I get overtime today, so it'll be fantastic."