Darryn Charles Buist (56), now a builder, labelled the incident on July 23 "a silly mistake".
"I’m not impressed with myself," he said.
The Dunedin District Court this month heard Buist had been driving to his Dunedin home from Central Otago on the Northern Motorway when there was a collision with another vehicle.
The ex-officer was not at fault but when police arrived on the scene he admitted consuming alcohol.
He had a breath-alcohol level of 547mcg - more than twice the legal limit - and said he had had "a couple of beers".
Buist told the Otago Daily Times that he stood by that description.
"Certain beers are certain [alcohol] volumes; some are higher volumes than others."
With so much experience dealing with offenders, Buist said there were often extenuating circumstances which led to people committing crimes.
And, he said, his situation was no different.
"I have a good understanding of what leads people to do certain things in life," he said.
"You never know the whole ins and outs but I’m not going to tell the public about my private life."
Counsel Joe O’Neill told the court his client was "very remorseful" and stressed that Buist had no previous experience on the wrong side of the law.
Community magistrate Simon Heale banned Buist from driving for six months, fined him $400 and ordered him to pay $130 court costs.
