Nick Calavrias jnr told Hawke's Bay Today it had been a "hard year" since his father passed.
At the time of the incident, the Wellington family had been spending time together in a holiday home his father had designed and built in 2010 in Lakeside, 3 Mile Bay.
"It was built in love for the family. That was dad's dream. He was all about family, he was all about grandchildren. We didn't have a big family and he treasured the time that we all got under the same roof."
His father was born in Romania, came to New Zealand at the age of two, a refugee from war-torn Europe and went on to become an Officer of the New Zealand Order of Merit (ONZM 2010) for his services to business. He also a leader in the Greek community.
In 1976 he founded Wellington Steel, which was eventually sold to Steel & Tube Holdings; where he held the position of CEO for almost 20 years.
On the morning of his father's death, Mr Calavrias said he had taken off early that morning to go mountain biking in the Rotorua Redwoods Forrest.
After a few hours he called wife Sarah, who told him she was still waiting for his dad to return from a bike ride. He was overdue by 45 minutes.
"The second she said that I knew something was up because he always takes his phone with him and if there was ever a puncture or a problem he'd ring someone up,
"She rang back 10 minutes later in tears."
Collecting himself as best he could, Mr Calavrias said he returned to Taupo to deal with the nightmare.
"Your mind just goes into a million different places. What can I say, that day was a blur."
From identifying his dad's body in the mortuary to helping his mum set up online banking and learn how to register a car, Mr Calavrias said life since his dad's death had been tough.
"It's life changing, it's absolutely life changing. I look at mum and she's broken, she's absolutely broken,
"Mum and dad had a relationship where dad would look after mum, the house, the financial things and she would look after other things. So she's missing that now, she really is."
Mr Calavrias said while it tore and continues to tear the family apart, it was the life they had now.
"You can't turn back the clock, what's done is done but it's just traumatic," he told Hawke's Bay Today recently. "It really is a traumatic way for someone's life to end."
After yesterday's Napier District Court sentencing of 22-year-old Samuel James Trotter, who was behind the wheel of the vehicle which hit his father, the bereaved son said the family's lives had been put on hold, and they struggle to accept how the tragedy happened, on a wide, 700-metre straight in clear conditions.
But he wasn't commenting on the outcome of the court case and the sentence of six months' community detention and nine months' supervision; Judge Tony Adeane noting Trotter, a high-achieving young man with an unblemished record, may also need help to deal with what had happened.
"It is a tragedy all round," he agreed. "At the end of the day, someone's lost a life in the most tragic circumstances. "What is appropriate?"
"Dad was simply out doing what he did most mornings, riding his bike on a beautiful, sunny day for exercise, some fresh air and to solve the world's problems or the problems of that day.
"Only this time he did not return."