Alec Vidot-Coleman: Crash expert cross-examined over speed of crash that killed girlfriend Scarlett Lenehan

A man who killed his girlfriend in a horrific head-on crash has claimed water, rubbish and worn out tyres contributed to the deadly incident.

Court scenes were tense as the speed a Sydney man was driving when his 20-year-old girlfriend was killed in a tragic crash was picked apart in hours of questioning that at times confused the judge.

Alec Vidot-Coleman pleaded guilty to dangerous driving occasioning death last year, after the 24-year-old’s Nissan Silvia ploughed into a Toyota Camry and caused the death of Scarlett Lenehan in West Ryde in December 2019.

The Carlingford man had initially pleaded not guilty to the charge but backflipped on his plea in Downing Centre District Court in February.

Ms Lenahan was a 2016 honour roll student at the exclusive Sydney girls’ school, Loreto Kirribilli. She died in hospital following the crash.

In a sentence hearing on Wednesday, Vidot-Coleman’s lawyer Brett Galloway said his client was “definitely not” travelling at 100km/h in a 60km zone at the time of the crash, as the Crown claimed, but was driving at 76km/h to 80km.

Alec Vidot-Coleman (left) and his late girlfriend Scarlett Lenehan

Mr Galloway also told the court water and rubbish on the road as well as tyres lacking tread contributed to the crash.

The crown prosecutor said the tyres were still roadworthy and only the inside of one had limited tread.

During a day of cross-examining Sergeant Fenton, the crash expert who wrote the report into the fatal collision, Mr Galloway questioned his methods used to determine the speed.

Alec Vidot-Coleman described himself as a Vidot-Coleman describes himself as an athlete, AFL development officer and an RSL club bar attendant. Picture: Nikki Short

Sergeant Fenton explained he uses a combination of CCTV footage and calibrating laser tools to create a 3D imitation of what occurred.

Mr Galloway asked: “So, in a 3D environment, where you calculate the speed of vehicle, it’s not done by mathematical calculation. It relies on the CCTV and therefore requires some personal judgement done by your eye?”

Sergeant Fenton responded: “No, not by my eye”.

“You look at the footage and you can see the vehicle is in line with the pole or whatever object, and within the 3D environment you locate the camera, and from the camera’s location we project a line through the line and across the road, and this projector dictates where this car should be,” Sergeant Fenton said.

Vidot-Coleman’s sentence hearing was part heard on Wednesday. Picture: Nikki Short

Mr Galloway asked what proportion of crash reports include this method, to which Sergeant Fenton said: “about 60 per cent of reports”.

Over several hours, Mr Galloway repeatedly questioned the methodology, down to how he determines the frame rate of CCTV footage.

At one stage, he asked Sergeant Fenton to make a metaphorical calculation on a predicted speed with his calculator.

Sergeant Fenton grew frustrated as he tried to explain that he does not use mathematical equations himself but relies on the 3D software, which was an “incredibly nuanced and intricate” process he’d been using for 12 years.

“My reports are 400 pages long… this form of analysis is incredibly common in crash investigations all around the world,” he said.

“Time and distance determining speed was shown to me long before I became an investigator.”

Judge Sarah Huggett and the Crown prosecutor struggled to understand several of Mr Galloway’s questions, with Judge Huggett saying she was lost and that neither she nor the witness could understand some questions.

She told Mr Gallaway his questioning was not helpful, saying Sergeant Fenton was an expert and “not a lay person estimating speed”.

The sentence hearing will return on Thursday where Vidot-Coleman is expected to give evidence.

In her sentence, Judge Huggett will also take into account two other charges of driving furiously in a motor vehicle to cause bodily harm in relation to two passengers of another car.