Robbie Rintoul, 68, was fatally struck by a lorry while walking away from his place of work after a driver failed to spot him before moving off.
His family said that they then endured a three-year battle for justice in the civil courts after prosecutors ruled out criminal charges or a fatal accident inquiry.
Police carried out a different investigation into the death because it happened on private property rather than if it had happened on a public highway.
Widow Jean Rintoul, 68, now fears families are being denied justice. She said: “The way Robbie’s death was investigated raises concerns about the way Police Scotland carry out its inquiries.
“If there was a murder on private ground the police would investigate the same as if it were in public so why is a traffic fatality treated differently?
“Those behind these policies need to rethink the investigating, recording and reporting of all deaths because no-one should be left without even a sense of justice because of a difference in process.”
Mr Rintoul was a blacksmith at Strathore Business Park in Thornton, Fife.
After finishing for the day on 4 February 2015 he made his way home on foot like he had for decades. But while exiting the site he walked past a parked lorry that had its engine running.
Lawyers say that the driver had left the vehicle running as he visited the site office and when he returned to the cab he drove off, knocking down Mr Rintoul.
The Crown ruled out an FAI claiming it was not a workplace death as Mr Rintoul clocked off just minutes before, even though he was still on the industrial estate.
An investigation for the civil action then found Police Scotland compile a Collision Investigation Report for fatalities on public roads but on private ones officers complete a Sudden Death Report.
But lawyers say that it is unknown why the two are treated differently.
Mrs Rintoul, a retired manager in social care, believes the incident also highlighted a need for all haulage vehicles to be equipped with more mirrors to reduce blind spots.
She added: “But the main issue is we now know there are gaps in the system of how deaths are investigated and I think it’s in the public interest to have these differences explained and rectified – no death should be treated differently just because of who the landowner is.”