The family were heading south, to Wellington along the Desert Rd when they had come to a stop in a line of traffic.
Despite having about 500m of visibility ahead of him, Barber crashed his truck and trailer unit into the rear of the family's car, killing one of the children instantly.
He declined to offer any comment when spoken to by police at the scene.
Fatigue key factor
The court heard fatigue was a key factor in the crash with Barber failing to have the minimum 10-hour breaks during the three days leading up to the crash.
On the day of the crash he had also worked continuously for 7 hours and 10 minutes. The maximum a driver is allowed to perform at one time is five hours, Senior Sergeant Martin McGahey told the court.
Barber was travelling south and failed to see the vehicles had come to a stop ahead of him.
He slammed into the back of the family's Toyota vehicle which was shunted forward into the trailer of a truck also belonging to trucking firm, Dynes.
The second truck was also shunted forward due to the impact of the crash.
Their oldest child, Arteen, 4, died of head injuries on impact, while their baby died two days later in Starship Hospital.
Mother's victim impact statement
Barber stood emotionless as Dr Sharifi read her victim impact statement to the court.
She said there were no words which could describe the emotional harm of what happened and said she could talk "for days on end" about what they were now going through.
She had since lost her job due to the moderate brain injury she had suffered, a frustrating consequence of the crash. She found it hard to cook and clean around the house let alone her top level job at AgResearch which she had since given up.
She was in hospital for 23 days due to the many injuries, while her husband was in hospital for two days.
Choking back tears, she described Arteen as a kind and loving boy who would often show random acts of affection and how much he loved his younger brother.
She wished to share more of her baby but they had only had him for two months.
"He really was too good to be true."
She now did not remember anything from the day of the crash until about 10 days later but told the court how her husband was in denial and shock about what happened.
Flashbacks were a common occurrence for her, although due to her memory loss she said she was unsure if they were from the actual crash or not.
She now felt guilty for falling asleep just before the crash and now wished she had been cuddling her boys or breastfeeding her youngest in the hope that it may have saved them.
"Every night is just drifting off to various nightmares of accidents … and waking up in the morning feeling more tired than the night before and starting a day with no aim or purpose or nothing to look forward to."
She was waking up to this so-called new life with shock, disbelief, anger, regret and negative energy she had not been able to let go of and which she felt would now stick with her for the rest of her life.
Birthdays, anniversaries and any other special day were now dreaded for weeks before and mourned for weeks after, she said.
While she'd suffered memory loss, she described how her husband remembered "every second and is living through it every day, over and over again".
"All that my mind has blocked out, he cannot let go of."
Her partner had the nickname of "Mr Safety", a name he'd had since they'd first met. He was constantly trying to protect everyone around him, she said,
He now carried an element of anger and recalled the day of the crash and how Barber's truck had been "tailgating" their vehicle and how he had been waiting for the perfect moment to get away from his truck.
Dr Sharifi spoke how much of a coincidence it was that the dashcam inside Barber's truck managed to stop working just minutes prior to the crash so there was no evidence available to the court.
She also expressed her anger at Barber sticking by his not guilty pleas up until this morning's trial.
"You have taken away the lives of two young innocent lives and as a result of that you have killed their parents on that day."
Barber was convicted on all charges and remanded on bail for sentencing in April.
He declined to comment when approached by the Herald outside court.
FATIGUE FACTOR IN CENTRAL NORTH ISLAND CRASHES
Taupō road policing manager Senior Sergeant Fane Troy said fatigue was a "big factor in a lot of crashes, especially through the Central North Island".
"Best practice is for everyone to stop every two hours and have a break. There is a cumulative effect of fatigure where days on end of not having sufficient sleep will catch up with you."
However, truck drivers could drive for five-and-a-half hours continuously before they were legally required to take a 30-minute break.
"They can also only drive 11 hours within a 24-hour period and they've also got to have at least one day of consecutive rest every seven days."
Troy said the case was a good reminder for all motorists that travel, be sales reps or truck drivers, that if they were travelling a lot of miles to comply with legislation and have regular breaks
COLLEAGUE CONVICTED
Meanwhile, Barber's colleague, who was driving the truck and trailer unit ahead of the couple, has also been convicted of careless driving after he had to swerve onto the wrong side of the road to avoid the line up of waiting traffic.
