The man accused of killing South Waikato man George Taiaroa in 2013 had a run-in with the roadworker a week before, the Crown has told the High Court in Rotorua.
But the accused man's lawyer has told the jury that his client had absolutely no reason to kill him.
Quinton Winders, 45, is charged with the murder of Mr Taiaroa, who was 67, at a one-way bridge near Atiamuri in South Waikato on 19 March 2013.
Mr Taiaroa died after being shot while operating a stop-go sign.
The trial opened today with allegations that a $980 insurance claim was the catalyst for Mr Taiaroa's death.
The Crown said, a week before the shooting, Mr Winders and his father were involved in a minor crash at roadworks being controlled by Mr Taiaroa.
Mr Winders' father had backed into another vehicle and the Crown said the accused blamed the roadworker.
The Crown's case is that Mr Winders returned to the site a week later and shot Mr Taiaroa in the head.
Crown prosecutor Amanda Gordon told the court the evidence against him was circumstantial as only one person saw the shooter flee from the scene.
She said no weapon had ever been found, and there was no DNA evidence linking the accused to the killing.
However, Ms Gordon said, the accused drove a blue Jeep Cherokee seen at the scene and owned a 0.22 rifle, similar to the one used to kill Mr Taiaroa.
Mr Winders was arrested at a Stratford property in November last year.
His lawyer, Jonathan Temm, said his client did not know Mr Taiaroa and had never met him or spoken to him.
Mr Temm said his client would have had to have travelled a round trip of more than 500km to be at the scene of the killing, within 10 minutes of Mr Taiaroa returning from a late lunch.
He asked the jury to focus on this, and what he said were wildly varying witness descriptions of the colour of the Jeep Cherokee seen at the time Mr Taiaroa was shot - and who was driving it.
Mr Temm said the police decided early on that Mr Winders was their main suspect and said the evidence had been made to fit that.
The trial is before Justice Toogood and a jury of seven women and five men, and is set down for four weeks.
The Crown intends to call more than 130 witnesses.