A South Australian truck driver who was ice affected and had slept just six hours in the two days before causing a fatal crash wept as he was jailed.
Timothy Walsh, 37, slowly veered off the Western Highway north of Horsham in July 2019 during what experts suggested was likely a microsleep.
When he realised his B-double truck's left tyres were in the grassy verge beside the road he overcorrected and the trailers tipped over onto the freeway.
It was just after 2am and the underside of the trailers, exposed to oncoming traffic, were dark.
Bus driver Emil Pich couldn't see the danger ahead until it was too late and his bus collided with Walsh's upturned trailers.
Mr Pich died as a result of the crash while three of his passengers suffered serious injuries.
One man, who had to be extricated from the wreck, suffered bleeding on his brain and serious fractures, while one woman still struggles with short-term memory issues.
Walsh pleaded guilty to one charge of culpable driving causing death and three charges of negligently causing serious injury.
He was jailed on Tuesday for 14 years.
County Court Judge James Parrish said Walsh had taken just a six-and-a-half hour break between arriving in Adelaide on July 10, 2019 and setting off again bound for Melbourne later that day.
During that time he washed the truck, played pokies and had some lunch before resting.
A sleep specialist analysed the truck's GPS data, which also showed when the truck engine was switched on and off, and found he'd had about four hours' sleep in the 24 hours before the crash and less than seven hours' sleep in the 48 hours before the crash.
He would have been suffering substantial sleepiness that could have caused impaired visual attention and an increased risk of microsleeps.
Walsh passed a roadside breath test after the crash but a drug test in hospital later found methamphetamine in his system at what a doctor said was a "high level".
Walsh said he had used drugs on the previous Saturday night but denied any use in the previous 48 hours, though the medical evidence suggested the use was more recent.
Judge Parrish said as well as being untruthful about his drug use, Walsh also told police he flashed the truck's high beams at Mr Pich's oncoming bus to warn him about the overturned trailers on the road ahead.
CCTV footage from the bus, which showed the truck headlights, proved that to be a lie too.
The court heard Walsh, who wept with his head in his hands as the sentence was handed down, had vowed not to drive a truck again after the crash.
Walsh, who has prior a conviction for failing to comply with truck driving work/rest rules, must serve at least eight-and-a-half years behind bars before he's eligible for parole.