Brett Collison, 43, was driving a small Hino truck along the motorway on the afternoon of June 21 last year when he collided with a Daewoo sedan travelling in the same direction.

The force of the impact shunted the car across a median strip into oncoming traffic, where it crashed head-on with a Honda.

The Honda’s front seat passenger, Joy Borjeson, was killed in the collision.

Her son Stephen, who was behind the wheel, received two broken ankles, while the driver of the Daewoo, Shane Gardner, suffered a fractured leg that required a rod to be inserted into the bone.

Mr Gardner was bedridden for three months and is expected to have ongoing problems as a result of his injuries.

Collison was originally charged with dangerous driving offences and  ordered to stand trial in Wollongong District Court at the start of the month.

However, on the morning it was due to proceed, he agreed to plead guilty to the lesser charges of negligent driving occasioning death and negligent driving occasioning grievous bodily harm.

The case was returned to Wollongong Local Court yesterday, where it was adjourned to January 15 for sentencing in order for the Borjeson family to attend.

Prosecutors yesterday indicated the family wished to read five victim impact statements to the court, and it was expected those, together with sentencing arguments from both sides, would take about two hours.

A set of agreed facts tendered to the court as part of the sentencing process said Mr Gardner was attempting to overtake Collison’s truck when the two collided in a 100km/h speed zone.

Witnesses estimated the truck was travelling at a speed of approximately 90-100km/h.

The force of the crash tipped the truck onto its side, causing it to spin along the roadway, but it was righted back onto its wheels after hitting a guard rail.

When Collison, who was uninjured in the crash, approached the still-trapped Mr Gardner and asked him what had happened, Mr Gardner said: ‘‘Are you f---ing kidding me? You just forced me into the other lane’’.

Collison later told a police officer that he had been trying to merge from one lane to another when the crash occurred.

The court heard a registered nurse passing by the site immediately after the accident stopped to give Mrs Borjeson first aid, however she could not be saved.

Collison was taken to Shellharbour Hospital for mandatory alcohol and drug testing.

Doctors discovered he had a small amount of cannabis in his system at the time of the crash, however, could not ‘‘form a firm opinion’’ that the levels found were sufficient to have impaired his driving. Collison admitted to police he’d smoked cannabis two nights before the accident.