Scott Hamilton, who was driving a Stirling Council recycling lorry, failed to check behind him before backing up to let another vehicle pass.
Hamilton, 44, had to manoeuvre to give the car space to get by on a single track road at Sheriffmuir near Dunblane, Perthshire.
He asked his colleague Lee McEwan to check the nearside mirror but neither of them noticed retired teacher Peter Wills was behind them.
Hamilton, of Bonnybridge, Stirlingshire, had denied causing Mr Wills’ death by dangerous driving. But yesterday on the second day of his trial at the High Court in Stirling before Lord Ericht, the Crown accepted his plea of guilty to the lesser offence of causing death by careless driving.
Sentence was deferred and he was banned from driving immediately.
The offence carries a maximum penalty of five years’ imprisonment.
Advocate depute Jane Farquharson said the original charge – which had alleged Hamilton had been “provided” with a trained reversing assistant but did not use him – made clear the basis on which the allegation of dangerous driving had been levelled.
But she said as Mr McEwan gave evidence it emerged that his position was “less certain”.
Mr McEwan, 18 at the time, said that he was not detailed to be a reversing assistant, or “banksman” on Hamilton’s lorry, which he claimed was not required to have a banksman because it was smaller than the council’s normal recycling trucks.
He insisted he was only on board to empty recycling boxes, and was “just an apprentice”.
Mr Wills, a skilled linguist, trained as a teacher after two years working for MI5 as a Russian interpreter. He taught in Falkirk, at the Wallace High School in Stirling and Stirling High School, where he was head of languages for 13 years. He was Russian examiner for all Scottish schools.
Last night his wife Virginia Wills, 80, said she bore Hamilton no ill will. She said her husband’s death had “devastated” their family.
But she said: “I don’t really care what happens to the driver, to be honest – I certainly don’t want him to go to prison.”
She added: “We would like to think that what happened to him has made people, and the council, more careful. We would like to think that by his death, perhaps, the death of a child, or a cyclist, in the future might be prevented.”