Road rager used car "like a weapon": Judge

A Victorian judge has slammed a former banker for using his car "like a weapon" to teach another road user a lesson, in a road-rage smash that killed a 10-year-old boy.

Judge Geoffrey Chettle said Ian Bouch, 48, wanted to terrorise a woman who was driving behind him and there was no way to "justify it".

Anisa Rage was driving carefully on Hopkins Road, Truganina, on May 27, 2014, when Bouch slammed on his brakes, forcing her to do the same, prosecutor Kevin Armstrong told the County Court.

A truck then smashed into the family's van.

Yahye Hashi, 10, died, his sister Yasmine, then 7, was seriously injured and their two brothers were also hospitalised.

Bouch's defence barrister Hayden Rattray said the Tarneit man braked in a "moment of madness", and hadn't intended to hurt Ms Rage.

"It wasn't a given that death would follow," he said.

Judge Chettle said Bouch wanted to terrorise her.

"He wanted to teach her a lesson," he said.

"This is actually using the motor car almost like a weapon."

Bouch has been found guilty of culpable driving and negligently causing serious injury over the fatal three-vehicle collision.

Ms Rage said in a statement read to the court Bouch, a father of two, did nothing to help at the scene.

"He was so unhelpful, so cold, so unsympathetic."

"What decent man could stand around and do nothing as children scream for help?"

Bilal Hashi, 13, told of remembering his sister screaming and covered in blood and seeing his brother on the floor not moving at all.

He said he felt like part of him was gone.

Included in his statement was a drawing of two boys playing soccer under the phrase "I will never get this back".

The court heard Bouch initially lied to police about the crash, trying to blame Ms Rage and the driver of the truck, Brett Kidd, who said he thought about the accident every day.

Judge Chettle heard Bouch has priors for dangerous driving and threatening behaviour.

In 2003 he cut off another car, then, after colliding with it, got out of his vehicle and kicked and punched the other car.

In another incident he tailgated a driver for 1km with his high-beams on and horn blaring.

Judge Chettle said he couldn't find a word in the English language to describe Bouch's behaviour.

"I can think of lots of indecent ones I can't use," he said.

Mr Armstrong said Bouch had shown no remorse for what he had done, but Mr Rattray disputed this.

He will be sentenced on Tuesday.