What Warren McDonald saw that day is unimaginable, so over time he has learned to shift his mind's eye back a bit.
Then he was the Australian Institute of Sport women's road cycling head coach. McDonald prefers to recall heady days in Italy, overseeing former Olympic rower Amy Gillett as she showcased her formidable "engine".
It was July 2005, the year after compatriot Sara Carrigan had won the Athens Olympics road race, and the world was their oyster.
Gillett had won bronze at the national time trial championships that year and was a key member of the AIS squad. They were Generation Next for Australian women's road cycling.
This is where McDonald will try to settle his mind on Friday - 20 years to the day since a teenage German driver lost control of her car on a country road and everything changed forever.
"I look back on the couple of days before the accident, when I was motor-pacing Amy. She was flying," McDonald tells AAP.
"She was obviously targeting this race, and just seeing her smile and grimace at the same time. It just hits home that she didn't come home - that really affects her family and friends.
"But for me, I try to look at those couple of days before, when Amy was Amy, and training really, really well."
Gillett and her AIS teammates - Katie Brown, Lorian Graham, Kate Nichols, Alexis Rhodes and Louise Yaxley - were on a training ride the day before the Thuringen Rundfahrt, a major women's road race.
The car drove head-first into their bunch.
Gillett died at the scene, Yaxley and Rhodes spent days in induced comas. All of Gillett's teammates suffered serious injuries.
McDonald, driving a team support car, was not far behind them. He was the first to be confronted with the trauma of what had happened.
This is Australian cycling's 9/11, or the death of Princess Di. Everyone involved in the sport on July 18, 2005 - and a fair few non-cycling people - can tell you exactly where they were and what they were doing when they heard the news.
Two decades later, while time has healed some wounds, the grief and the sadness and the "what-if" remain profound. As always, it is complicated and people have dealt with it differently.
Gillett's teammates had long recoveries that fundamentally affected their cycling careers, to varying degrees. For example, Rhodes won bronze at the 2008 time trial nationals. Graham narrowly missed selection for the 2008 Olympics.
But all their lives pivoted on that day.
Compatriot Kate Bates, then 23, was in the midst of a cycling career that featured the Olympics and a world track title.
She now is managing director of the Amy Gillett Foundation, formed in the wake of the accident, which advocates for road safety and aims to improve the often-vexed relationship between cyclists and motorists.
Bates speaks of the "butterfly effect" of what happened 20 years ago.
"It wasn't about us, but there's no denying the life-changing impact it had on all of us," she said of Australian women's road cycling.
"On reflection, as you get older, it means more."
Bates wants the foundation to reflect what Gillett wanted in her sporting career.
"She was very ambitious, very courageous, very bold - that's what the foundation should be ... never give up," Bates said.
"It's more important than it ever has been. As of May 31, it was Australia's deadliest 12 months on the road since 2010.
"There are some things that have changed, but certainly not enough has changed."
Asked about the foundation's purpose, Bates is blunt: zero cyclist deaths on Australian roads.
A new online campaign will be launched next week to mark the anniversary and aiming to improve attitudes and behaviours, titled simply "It Starts With Me".
A couple of years after the accident, a top rider privately admitted she was quitting the sport before time. She no longer felt safe enough on her bike.
It is an age-old maxim in the sport that there are two sorts of cyclists - those who have crashed, and those who are about to. But this was fundamentally different.
Two decades later, Australian cycling has celebrated Grace Brown's Olympic gold medal and Sarah Gigante's two stage wins in the Giro d'Italia. But safety remains a massive issue in the sport.
McDonald and his wife Sian are the parents of two teenage boys, Fionn and Dash. In the midst of a phone interview that is often fraught, there is a ray of light when McDonald is asked about how the accident changed him.
"The life of a uni student - he just got out of bed (in the afternoon). How's that? He goes back to uni next week," McDonald said of Fionn and bursts out laughing.
Once Dash has finished school, McDonald and Sian will go to the accident site. It will be his first time there since that terrible day.
To know the McDonalds, witness the dignity of Gillett's parents Denis and Mary and her husband Simon, be awed by Rhodes' toughness on a bike and come to know Graham's impish sense of humour, the last 20 years bring an awful reminder.
Terrible things sometimes happen to great people.
Mary has written a heart-rending letter to her daughter to mark the anniversary, published on the foundation website.
"Please keep riding those rainbows - there are many of us looking out for you," Mary says.
