A truck driver was affected by drugs when he slammed into a trailer parked by the side of a country road, killing a 26-year-old woman and her 10-year-old son and seriously injuring her three other children, the WA District Court has heard.
Carl Allan Bridge is on trial accused of dangerous driving causing the deaths of Amy Bropho and her son Leroy Dawson on the night of August 19, 2018.
He is also facing charges of dangerous driving causing grievous bodily harm to Ms Bropho's three other children, who all suffered life-threatening injuries.
The family was returning home to the wheatbelt town of Corrigin, about 300 kilometres south-east of Perth, when their car, being driven by Ms Bropho's partner and the children's father Leroy Dimer, ran out of petrol.
While Mr Dimer walked to Corrigin to get fuel, a prime mover being driven by Mr Bridge that was towing two empty grain trailers smashed into a trailer attached to the family's car, causing it to roll.
Prosecutor Sean Stocks said a blood sample taken from Mr Bridge found that he had used methylamphetamine one to two days before the crash.
Cannabis was also found in his system at levels that indicated he had used the drug earlier that night, or while he was driving.
"This case is about a drug-affected driver who should not have been driving but made a choice to use methylamphetamine and cannabis and get behind the wheel because it was convenient to do so," Mr Stocks said.
The court was told the headlights on Mr Bridge's truck were found to have been on low beam at the time of the crash and he later told police in an interview he did not know why he had not turned them on to high beam.
Mr Stocks said when that happened spotlights were also activated on the truck which would have further illuminated the road.
"Had he had full beam lights on, his ability to avoid the collision would have been significantly increased."
"You will hear from every other driver, they were using full beam headlights (and) they saw Mr Dimer's car and were easily able to aovid it.
"Every other driver except Mr Bridge, the truck driver who used methylamphetamine and cannabis, the truck driver whose ability to drive was impaired … the truck driver who only had low beam on."
Car parked 'predominantly' on road, defence argues
Mr Bridge has pleaded not guilty to all five charges against him.
In an opening address, his lawyer Bernard Standish said the issue for the jury would be to determine whether his client's drug use had impaired his ability to drive to such an extent that he was incapable of controlling his vehicle.
Mr Standish told the court the family's car and trailer were parked "predominantly" on the road surface, and "only a small part" of them were off to the side.
Mr Standish said the crash happened in the middle of the night and witnesses would testify that the car's lights were off and there were no reflectors on the trailer.
He also said that truck drivers were permitted under WA law to drive with low beam lights on and there was no requirement for them to use high beam.
Mr Standish said there was evidence his client did react after seeing the car, with skid marks extending for about 40 metres indicating that the wheels of the truck had locked up.
"The defence says you will be satisfied he responded appropriately notwithstanding the level of drugs in his system," he said.
Mr Dimer saw fire truck, ambulances pass
The first witness was Leroy Dimer, who testified he had wanted to wait in the car to try to get help from a passing motorist.
However, he said when no cars passed, Amy Bropho said one of them needed to start walking so he got out to get help.
Mr Dimer said he did not leave the lights on because he did not want the battery to go flat, and he also could not find the button for the hazard lights.
He said he got about halfway back to Corrigin when a fire truck travelling in the other direction pulled up to ask if he had called in an accident.
He said the truck left when he told them it was not him.
Mr Dimer said he then saw two ambulances drive by before police from Corrigin picked him up and took him in to town.
The trial is expected to end later this week.
