This year marks the 30th anniversaries of Australia's most devastating bus crashes — terrible accidents that led to major upgrades on the Pacific Highway in New South Wales that saved countless lives.

Key points:

It is 30 years since Australia was shocked by two bus crashes that killed 56 people and injured 63

It is 30 years since Australia was shocked by two bus crashes that killed 56 people and injured 63 Emergency workers who attended will never forget what they saw

Emergency workers who attended will never forget what they saw Fatalities have halved since the Pacific Highway has been upgraded

On October 20, 1989, a bus and a semi-trailer collided on a straight stretch of the Pacific Highway at Cowper, near Grafton in northern New South Wales, killing 21 people and injuring 22 others.

It was the worst loss of life on Australian roads; an inconceivable tragedy.

Just two months later on December 22, the unthinkable happened.

Two buses full of people heading home for Christmas crashed head-on in another rural area at Clybucca, just north of Kempsey.

Thirty-five people died and 41 others were injured.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 1 minute 40 seconds 1 m 40 s Cowper bus crash 20 October 1989 ( ABC Archives )

The crashes led to two inquests by state coroner Kevin Waller who recommended the entire Pacific Highway be made a dual carriageway from Newcastle to the Queensland border.

First on the scene

One of the first people on the scene of the Cowper bus crash was Dieter Meszaros, then deputy controller for the Grafton State Emergency Service's road rescue team.

"A call came at nearly 4am on October 20 that we had a very serious bus crash," Mr Meszaros aid.

"The second call came through and said that there were many dead and many injured.

"That's when it really hit home because never had the police put such a message across."

When Mr Meszaros arrived, it was obvious that a bus and truck had collided, but he was surprised there were no people milling around and it was eerily quiet.

Dieter Meszaros was one of the first to arrive at the scene of the Cowper crash. ( Supplied: Dieter Meszaros )

He looked inside the bus and realised the passengers were all still inside, seriously injured and deceased.

"I got my car as close as I could to unload the bulk stretchers and I certainly noticed that there were hardly any people standing around.

"We had a bus rollover about six months prior and there was a lot of people standing around.

"This time there was nobody standing around and it was when we poked our heads into the bus I noticed they were all inside the bus."

"It was all quiet. There was no screaming, there was nothing," Mr Meszaros said.

Ray Walkden was duty officer at the Kempsey State Emergency Service at the time of the Clybucca bus crash.

He got the call about the accident at about 3:20am on December 22.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 2 minutes 7 seconds 2 m 7 s The day after the Cowper bus crash ( ABC North Coast: Catherine Marciniak )

"Two buses head-on and they're both full," he said.

"We had people hanging out of windows, people screaming inside.

Inquest found driver had fallen asleep

A NSW coronial inquiry found a McCafferty bus driver fell asleep at the wheel and hit the oncoming TransCity coach.

"It was narrow, and fatigue was always the biggest problem that we had along that area," Mr Walkden said.

"People coming from Sydney had been driving five to six hours before they got to Kempsey. When they drive from Brisbane, they were nearly five to six hours from Brisbane.

"We were in the middle of everything in those days."

The first vehicles to used the Frederickton to Eungai Pacific Highway upgrade near Kempsey. ( ABC Far North: Emma Siossian )

Work was carried out at the Cowper bus crash site after the accident there.

"We've also carried out ongoing safety improvement works on the existing highway," Anna Andrews, from Roads and Maritime Services, said.

"The good news is that the final link between Woolgoolga to Ballina will be progressively opened to traffic over the next year or so, with it being fully opened to traffic at the end of 2020," she said.

The challenges with duplicating nearly 700 kilometres of highway between Newcastle and the Queensland border meant priorities had to be made, Ms Andrews said.

"We looked at the areas with the poorest safety record as an example. Where were we seeing the highest levels of fatal and serious injury crashes?

"We obviously prioritised those sections and the delivery of that upgrade first.

"We looked at where were the highest volumes of traffic and then obviously worked through the other challenges, balancing those as we went through."

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 2 minutes 51 seconds 2 m 51 s Coroner report on the Cowper bus crash inquest ( ABC Archives )

The Glenugie and Ballina section of the highway will be opened by the end of 2020.

Road toll down

Fifty fatalities occurred annually on the Pacific Highway when the upgrade started, but that has more than halved since.

Last year there were eight fatal crashes, Ms Andrews said.

"There's still more work to do but we are continuing to see that trend go downward."

Mr Meszaros said that a few decades ago, it was common for Grafton's road rescue team to be called out to four road accidents a month, and half of them were people trapped in cars or crash fatalities.

He said this was now rarely the case.

"The road deaths are far less, the collisions are far less.

"It goes back to improvements in cars, improvements in the roads, all these steps that have been taken are working."

Remembering the lives lost

Mr Walkden is now working on getting in touch with the people who came to the 20th anniversary of the Clybucca disaster.

"We had two or three families … who lost people in the accident.

"They were saying thank you to us and they come back every year.

The memorial at Clybucca. ( Supplied: Monument Australia )

"We still have people in town here, some of the rescue blokes, fire brigade around the place.

"The hospital, they are the unknown people, the hospital staff.

"The ambos had treated the people, bandaged them up as best they could, then got them to the hospitals."

Mr Walkden is involved with the Lions Club that maintains a memorial garden.

"I'm there all the time whereas other people aren't there," he said.

"I've had people come in from Victoria, just dropped in, lost grandma or aunty in the accident.

"They say thank you for doing it.

"We were there for you at that time, we're still here for you now."

A commemorative service is being held at the Cowper bus crash site today to mark the anniversary.

