A professional race car driver has told court an Adelaide driver probably accelerated his Lamborghini in "sports mode" before hitting teenager Sophia Naismith.
Racing and stunt driver Luke Youlden was giving evidence in the Adelaide District Court where Alexander Campbell has been facing trial over the 2019 fatal crash.
In June 2019, Sophia and her then-15-year-old friend were walking along Morphett Road in Adelaide's south-western suburbs to a friend's house when they were hit.
The car had also mounted a kerb and crashed into a Glengowrie restaurant.
After looking at a diagram of the crash, Mr Youlden told the court that the car was probably in sports mode before Mr Campbell lost control of the vehicle.
"I would think sports mode at the very least," the advanced driver trainer said.
The diagram showed where the car began losing control, where tyre marks started on the road.
Those marks veered off the road and turned left into the restaurant.
Mr Youlden — who was co-driver in the vehicle that ultimately won the 2017 Bathurst 1000 — said the nature of the marks indicated hard acceleration had caused them.
"Just the nature of the marks — they've just basically gone hard left," he said.
"If the driver was looking to where he wanted to go it would be much straighter than that and the stability control would have actually engaged."
'Unusual' to slip in safe mode
The expert witness said a car in sports mode slips much more easily and would only have to lose a bit of traction to begin slipping.
"Cars just do not drive down the road at 53 [kph] and then turn left — it has to respond to an input," Mr Youlden said.
"Looking at this, and knowing the car, the only way it'Fs going to turn like that is to get on the gas excessively."
Mr Youlden said it was unlikely that the car would have lost control in "strada" or "safe mode", which were driving modes of Lamborghinis.
"I wouldn't say it's impossible — but it's very unusual to lose that much slip in a safe mode like that," he said.
The Supercars series driver was also asked if it was possible a Lamborghini Huracán could be in strada mode with moderate throttle and experience the same loss of control as Mr Campbell did.
"Not in my opinion, no. If it was moderate and started to accelerate slowly — [it] would shift its weight to the rear and drive down the road straight."
Lamborghini mounted kerb
Through questioning from Mr Campbell's defence lawyer, Craig Caldicott, Mr Youlden said that, since 2016, he had driven a Lamborghini Huracán three times in strada, sport and corsa modes.
Mr Youlden said he'd never lost control while driving a Huracán.
"Controlled slippage yes, but never spun out," he said.
Mr Caldicott said an expert reconstructionist had found the car had first turned left, then right and other material from the scene showed the car had left brake marks.
"If the car was in sports mode, there was moderate acceleration, the temperature was at seven degrees [Celsius], or thereabouts, and the car was changed up a gear and the car then proceeded to move left then right and mounted a kerb — is that a possibility?" Mr Caldicott asked.
"Yes, that's a possibility," Mr Youlden said.
The matter returns to court on Friday.