But the camera was not equipped to relay that information to police in real time, and they were unaware of it when they were advised of subsequent dangerous driving by 21-year-old law student Harrison Kitt, counsel assisting the coroner Martin Kirby told the Adelaide Coroner's Court on Tuesday.
Coroner David Whittle is conducting an inquest into the deaths of Detective Chief Superintendent Joanne Shanahan, 55, and Tania McNeill, 53, who were killed in a three-car collision in April 2020.
The crash occurred when Mr Kitt drove through a red light at an intersection in Adelaide's south at more than 160km/h.
Mr Kitt pleaded not guilty to two counts of causing death by dangerous driving and one count of causing harm and was found not guilty because of mental incompetence.
He is now subject to mental health and parole board supervision while living with his parents. In January 2022, the District Court set that period, known as a limiting term, at 10 years.
Opening the inquest, Mr Kirby said a fixed speed camera on Victor Harbor Rd, near Tatachilla, captured a photograph of Mr Kitt travelling at 187km/h in his parents' Volkswagen Amarok utility at 12.41pm, 59 minutes before the fatal crash.
He said the picture was the first indication Mr Kitt's driving posed a danger.
"Information recorded by that camera would likely have been of great importance at the time, as it would have provided a registration number for the vehicle and a photograph of the driver," Mr Kirby said.
Mr Kirby emphasised that the inquest was not exploring Mr Kidd's mental health, or the police response, and it had a "narrow scope".
"The fact that this dreadful collision occurred following a spate of high-speed, dangerous driving by a young man experiencing his first psychotic episode is not in question," he told the court.
The inquest would focus on the resources that were available to police in the hour before the fatal collision, he said.
"It will explore whether the South Australian police had the tools they needed to identify and intercept Mr Kitt. And if not, what, if anything, might help prevent a similar event happening in the future?" he said.
Witness statements later helped police establish that Mr Kidd drove from his parents' beach house in Encounter Bay to their home in suburban Urrbrae via Victor Harbor Rd and the Southern Expressway.
Motorists on the Southern Expressway reported the car speeding and weaving through traffic, but no one was able to record a registration number so police were unable to intercept, identify or locate it, Mr Kirby said.
Mr Kidd remained at his home in Urrbrae for 30 minutes and friends who arrived there noted he was behaving in an "odd, erratic manner".
As Mr Kidd drove away, a friend called triple zero for an ambulance because he believed Mr Kidd was suffering a psychotic episode.
"Approximately one-and-a-half minutes later, the fatal collision occurred," Mr Kirby said.
Traffic Management Centre manager Michael Sutton gave evidence about how SA's traffic camera network operated, both at the time of the crash and now.
He said the government radio network now enabled the centre to pass information directly to South Australia Police, and he believed the working relationship between the two government entities was the best in the nation.
Outside court, Mrs Shanahan's husband Peter said he was very grateful the coroner was investigating whether anything could be done to improve road safety.
"That's really important to everyone and to me and the community," he said.
"If we can do something better and we can save one more life, this is all worthwhile. Hopefully, there can be some recommendations that come out of it that's very positive."
The inquest is continuing.
