Constable David Brown, 30, wept as the jury of 10 women and five men brought back a verdict of not guilty after deliberating for four hours.
He walked free from the High Court in Glasgow after being found not guilty of causing the death of 65-year-old John Lacon by crashing his police van into Mr Lacon's Fiat Doblo on April 29, last year, at the junction of Dorchester Avenue with Great Western Road, Glasgow.
The officer, who is now working in police intelligence, said: "Thank you, my lord," before leaving the court and hugging his family.
In June this year Constable Brown offered to plead guilty to a reduced charge of causing Mr Lacon's death by careless driving, but this plea was rejected by the Crown.
The jury could have convicted him of this reduced charge, but chose not to. The court heard that PC Brown was responding to three officers-in-danger emergency calls after a riot broke out at Kelvin-grove Park during the Royal Wedding celebrations.
Mr Lacon sustained head injuries and died in the Western Infirm-ary on May 11, last year.
Mr Brown admitted that he made an error of judgment but said he only had a split second in which to react and he thought Mr Lacon's taxi was slowing down.
Mr Brown admitted to Iain Mc-Sporran, prosecuting, that he made a mistake in going through the junction and said he now has to live with the consequences.
He added: "What I am going through is nothing compared to the suffering of the family of Mr Lacon."
Mr Lacon's family said they were "deeply shocked and disapp-ointed" at the verdict.
The relatives added: "We hoped this process would at least reveal the truth surrounding John's death.
"This has only compounded our feelings of injustice."