THE son of a Sydney woman who was tragically killed when a truck struck her on a pedestrian crossing has revealed the heartbreaking moment he first heard the news.

It’s alleged Sydney truck driver Emmanuel Xiberras didn’t stop when he struck Jo-Ann Thwaites at a Brookvale intersection, with the 61-year-old’s clothing stripped as she was dragged below his Lilydale chicken truck.

The 38-year-old is on trial in the NSW District Court after pleading not guilty to dangerous driving occasioning death, and failing to stop and assist after the crash on the morning of May 20, 2016.

A jury has heard that Xiberras was seen removing clothing from underneath his vehicle and throwing it in a bin after he fatally struck Ms Thwaites on a pedestrian crossing.

The victim’s son Nicholas Thwaites today told the court he first learned of the incident in which a pedestrian had been struck on his car radio while driving in the northern beaches.

“I heard (on radio) there was an incident in Brookvale and the traffic was backed up all the way past Manly Vale and I drove home accordingly to avoid the traffic,” Mr Thwaites said.

Earlier that day, he had offered his mother a lift home before she left to get her car serviced, but she declined because she wanted to walk and do some shopping, the court heard.

“When I first got home and found mum was not at home … I got this really sick feeling in my stomach and panicked and tried to call mum and couldn’t get through,” he said.

“So I drove to where the incident had happened.”

Mr Thwaites said he told police officers on scene that he was unable to reach his mother who was visiting the area. About half an hour later, he was informed that the woman who had been involved in the incident, was Ms Thwaites.

A second witness, who can’t be named for legal reasons, testified that he was travelling in the passenger seat with his mother when he saw Ms Thwaites “stumble” as she went to step onto the pedestrian crossing and stumbled.

She put her hand out to try and stop herself but fell and went under a wheel of Xiberras’ truck, the court heard.

The boy, now 15, said Ms Thwaites let out a short scream when she was then struck by the truck.

“There wasn’t much force but it looked like she tried to hit it to make a noise,” he told the court.

“I heard one scream and then it stopped …

“It wasn’t loud because she couldn’t get full breath out. It was like half a scream and it wasn’t very high pitched. It was quite low.”

The truck then looked like one that was “going over rocks on a mountain”, the jury heard.

“I turned to my mum and told her what happened then we looked back and we couldn’t see her.

“I kept looking back, the driver just kept driving normally.”

Another woman - who didn’t see the collision but saw the aftermath - said she saw a “leg sticking out of the truck”.

In his opening address, Crown prosecutor Roger Kimbell said Ms Thwaites’ body was dragged for some distance before she dropped onto the road and was struck by a second vehicle.

He said several people later saw Xiberras removing or trying to remove what looked like clothing underneath his refrigerated Isuzu truck. One witness is expected to give evidence that she saw him put it in a plastic bag and put it in “what she describes as a big council bin”, Mr Kimbell said. He alleged that if Xiberras was paying attention he would have seen Ms Thwaites on the crossing, and that he didn’t stop when he knew or ought to have known what had happened.

But defence barrister Richard Pontello said Xiberras stopped and looked both ways before driving onto the crossing.

He said in his opening address that in circumstances where Ms Thwaites tripped and fell into his client’s truck, there was nothing he could have done to avoid the tragedy.

When Xiberras felt a bump he thought he’d hit rubbish, and in his mind that suspicion was confirmed when he looked under his vehicle and saw what he thought were cloth rags.

“He had absolutely no idea that he had hit a person … and he had no reason to think that he had done so,” Mr Pontello said.

“The only reason that he disposed of what turned out to be Ms Thwaites’ clothing is that he thought he’d run over rubbish only.” The trial continues.