Passengers aboard the Lightning Ridge to Dubbo coach service had some heart-stopping moments last Friday 19 July at around 5.20pm as they watched a potential highway tragedy unfold.

A small red Suzuki attempted to overtake the NSW Trainlink bus at a roadworks site about forty five kilometres south of Walgett, only to lose traction in loose gravel before rolling off the road.

The vehicle came to rest on its roof.

A group of passengers and drivers from following vehicles rushed to roll the vehicle back onto its wheels.

The driver, a 52 year old Iranian-born school teacher from Walgett was miraculously uninjured.

Emergency services from Coonamble were called to the scene, along with police and ambulance from Walgett.

"We saw it happen from about a hundred metres away," said the driver of a car travelling behind the Suzuki.

"The bus was doing about 40 kilometres an hour and he was doing a bit more.

"He just hit the gravel and it was so soft and fluffy those skinny wheels just cut right through it.

"There was an embankment about 1.5 to 2 metres deep and he went straight over that and ended up on his roof."

The driver of this vehicle escaped relatively unscathed.

"He missed a massive sandstone boulder by about a metre - it would've been a whole different story if he'd hit that," the witness told the Western Plains App.

The car was crushed and undriveable but the driver, who was assessed at the scene, was shaken, shocked but otherwise unhurt.

“He was very lucky,” the witness said. “It was just lucky he had his belt on and was going slowly.”