The man behind the wheel of a sewage truck that smashed into two cars at the base of a freeway in Adelaide, killing two people, has told a court how he tried in vain to slow down.
The 34-year-old has given evidence in Adelaide Magistrates Court in the commonwealth prosecution of waste company Cleanaway.
He told the court how he had been driving for the company for less than a week before the crash in August 2014 and how he tried to slow the truck with its brakes so he could change into a lower gear as it gathered speed.
"I was trying to slow it so I could get it into a lower gear," he said.
"There was no air in the brakes. It was going too fast to shift."
He ultimately lost control of the truck which ploughed into two stationary cars at the base of the South Eastern Freeway, killing Jacqueline Byrne, 41, and Thomas Spiess, 56.
He was also severely hurt in the crash and lost a leg.
Commonwealth workplace safety regulator Comcare is prosecuting Cleanaway over seven counts of failing to comply with its health and safety duty.
The truck driver, who had been given immunity from criminal prosecution, said by the time the truck had started to gather speed and he hit the brakes, it had already passed the final arrester bed on the freeway that trucks can use as emergency exits.
It was put to him that by that time he was "standing on the brakes and there's nothing there for you".
He replied: "Yes".
It was his first time driving the truck involved in the crash, which he described as older than others he had driven in his first few days with Cleanaway and had a manual, rather than an automatic, transmission.
It was also his first time driving any truck down the freeway.
The court also heard how he probably would have made the trip down the freeway with an empty truck had a sewage depot in the Adelaide Hills been able to take his near 8000-litre load that day.
It meant he was diverted to a depot at Bolivar, in Adelaide's north, instead.
Outside the court, Jan Spiess, the wife of one of the victims, who has always supported the driver, said he could now put the matter behind him.
"It's over for him now," she said.
"He's just as much a casualty of this disaster as all of us."