Grim details emerge about the possible cause of fatal NSW crash that killed Greyhound bus driver on Hume Hwy at Kyeamba

Fatigue is being investigated as the possible cause of a devastating crash that killed a man and injured 13 other people on the Hume Hwy in NSW’s Riverina region in the early hours of Saturday.

A Greyhound bus crashed into the rear of a B-double truck on the highway at Kyeamba, about 50km south of Wagga Wagga, about 3.35am.

WATCH THE VIDEO ABOVE: Possible cause of fatal Hume Hwy crash investigated

Now, police believe that the heavy vehicle in front of the bus may have slowed as it made its way up hill, and the investigation will look at whether this change in speed played a role in the crash in the northbound lanes.

The bus driver, belived to have been a 32-year-old Victorian man, was treated by paramedics but died at the scene.

“It appears from early indications that the bus collided with the rear of the semi-trailer as it went up a steep incline here at Kyeamba Gap,” Murray River Police District Chief Insp. Scott Russell.

It is not clear whether the driver saw the truck ahead of them before the crash, and this will also form part of the investigation.

There were 13 Greyhound passengers treated for injuries, including broken bones and lacerations.

The passenger believed to have sustained the worst injuries was a male whose leg was broken in the crash, police said.

There had been about 40 passengers onboard at the time, including tourists and people heading home for the holidays.

The bus had been travelling to Sydney from Melbourne and was scheduled to stop at Albury and Canberra along the way, but crashed before reaching the penultimate destination.

“Forty passengers, none of them with life-threatening (injuries), yeah we’re very lucky to get away with just the one casualty,” Russell told 7NEWS.

He added that “one deceased is one deceased too many”.

The tragedy has prompted a warning from paramedics as traffic ramps up over the festive period.

NSW Ambulance inspector Jennifer Barker said: “There’s just going to be more traffic on the road, (drivers) just need to be aware and take more safe precautions. Make sure you wear a seatbelt, have plenty of rest.”

‘The reality set in’

One passenger on the Greyhound, Lily Harper was sleeping when the bus crashed, and sustained a fractured nose, cuts and bruises.

“I woke up to my head hitting the seat,” she told 7NEWS.

“The reality set in after a few minutes when we hadn’t got off, and we realised we couldn’t get off without smashing the window. That’s when we kind of panicked a bit.”

“The worry was, at least for me, that another car or something would hit us.”

The bus company Greyhound Australia shared it condolences in a statement on Saturday.

“We are heartbroken that the driver ... has died after a motor vehicle accident at Kyeamba in the NSW Riverina region in the early hours of this morning,” Greyhound Australia spokesperson Michael Leard said.

“This is a tragic incident, and our deepest sympathies go out to his family and friends.

“Several passengers received non-life-threatening injuries and are currently receiving medical treatment. We are offering support to all those involved in this tragedy.

“We are working closely with authorities to assist them with their investigation in understanding the course of events that have led to this accident.

“Assistance is also being provided to the entire Greyhound Australia team, who have been greatly impacted by this devastating event.”