A judge warned that some drivers are treating roads like their own personal racetracks as he jailed a teenage motorist for careless driving causing the death of a 16-year-old girl.
Judge Eugene O'Kelly jailed Edward O'Shea (19) for 14 months after noting that Katie Murphy had sent a Snapchat video to a friend just seconds before the crash in which she said they were: "Probably going to die in the car."
An unidentified male voice replied: "Yeah, probably."
A female voice then said: "Cheeky - going over the speed limit."
An unidentified voice replied: "Cheeky - going twice over the speed limit."
A Waterford Circuit Criminal Court jury was not shown the social media videos during the trial because they were deemed to breach the hearsay rule.
Judge O'Kelly said Ireland now had to review such real-time video evidence from social media in the trial context.
In jailing O'Shea, who was 17 at the time of the accident, he said his careless driving was at the upper end of the scale.
He also said it "beggars belief" that O'Shea, a learner driver, could treat such a powerful car as his own.
"Some drivers, particularly young men, treat the roads as their own private racetracks and do so without any regard for the potentially catastrophic consequences for other road users and indeed for themselves," Judge O'Kelly said.
He said the so-called Clancy Amendment about unaccompanied learner drivers could not apply as the crash happened before it was passed into law.
However, he noted how O'Shea had been driving a powerful and modified Toyota unaccompanied. "Such driving is not only illegal, it is dangerous," the judge added.
The heartbroken Murphy family said they had lost their only daughter because O'Shea lost control of a powerful modified car while showing off to his friends.
O'Shea was jailed after being convicted of careless driving causing death and careless driving causing serious injury.
He was acquitted by the jury last February of dangerous driving causing death.
Katie died when the Toyota, which had a specially lowered suspension, spun out of control and collided side-on with a wall outside a Tramore housing estate on October 5, 2016. The car also had low-profile tyres and a side skirt.
The speed limit at the scene was 50kph but because there were no brake marks it was impossible for gardai to determine what speed O'Shea was driving at. Forensic experts were able to determine only that the car finally hit the wall side-on while travelling at around 32kph.
However, locals had noted the sound of a car travelling at speed along the winding Cliff Road. One woman was so alarmed that she got out of her armchair to investigate - and seconds later heard the sound of the impact.
Two other teenage passengers, Joseph Walsh and Jessica Fynn, suffered horrific head and chest injuries in the accident in Newtown, outside Tramore.
The car, which had a twin-cam engine, was registered to the O'Shea family garage, run by his father Michael, and Edward was driving it under a garage insurance policy.
"It was extraordinary and blatantly irresponsible for the O'Shea garage business to facilitate the driving of such a car [by a young learner driver]," Judge O'Kelly said.
O'Shea, who appeared in court wearing black trousers and a navy shirt and tie, sat with his head bowed as victim impact statements were delivered by Katie's parents and her brother, Scot.
The defendant, in a letter handed in to the judge, apologised for what his careless actions behind the wheel had inflicted on three families.
"If I could change what happened, believe me I would change everything," he said.
The court heard that O'Shea now suffered from survivor's guilt, depression, anxiety and post-traumatic stress disorder.
He had been seeing a counsellor for more than two years and had been subjected to social media condemnation over what had happened.
"I hope that one day you [the Murphy family] will be able to forgive me but I want you to know that I am truly sorry. So many people have been affected by my bad judgment that day," O'Shea added.
Joseph Walsh's parents handed in a letter in which they said they held no ill will toward the driver.
O'Shea, an apprentice mechanic, had offered a plea to careless driving causing death and serious injury before his trial started.
He had been driving on a provisional licence for five months when the tragedy happened.
Katie, of Castlewoods, Ballinamona, Waterford, was a rear-seat passenger in the car along with her friend Jessica.
O'Shea, of Magnh, Fenor, Waterford, was also disqualified from driving for six years and fined €800.