Motorists could be driving over a possible deathtrap every day on one of Northern Ireland's busiest roads, it has been claimed.
A Co Down couple say part of the carriageway passing their business is constructed over potentially unstable rock-filled cages.
Alan and Elizabeth Lemon have been locked in a three-year battle with officials over the stretch of the A20 road near Newtownards.
They have gathered reports from a consulting engineer who concluded that the section of road is dangerous and could develop a "catastrophic failure".
Despite raising their concerns with the Department for Regional Development (DRD) in 2012, the Lemons are still waiting for satisfactory answers.
Mr Lemon said: "We've been warning for the last three years that the road is a potential danger. The cages which part of the road is built on are not meant to be driven on. The road is unsafe, we've got reports which show that, and yet nothing has been done about it."
The A20 carries around 10,000 vehicles a day, including school buses. Mr Lemon explained that gabion cages - steel wire structures filled with rocks - were installed more than 15 years ago.
They were placed behind steel sheet piles, which were inserted to support the edge of the road passing alongside their business.
The cages were then buried under what became a grass verge running next to the property.
However, Mr Lemon said resurfacing works in 2012 saw the road realigned. The grass verge was removed with the new kerb line and the edge of the road both now running over the gabion cages.
A company which manufactures the cages has said they are not designed to support road traffic.
The Lemons commissioned Dr James Leinster, a consulting civil and structural engineer, to produce two reports on the issue.
The first said: "It is considered that the possibility of a catastrophic failure of the gabions cannot be discounted, particularly where heavily loaded vehicles are concerned."
It adds that such a failure "could have serious implications, even putting at risk the lives of road users and the occupants" of the Lemons' address.
There is a sizeable drop from the road to the Lemons' property.
According to Mr Lemon, the bank supporting the road is breaking up and falling into a garden.
Boulders have been shaken loose and seven vehicles have also crashed on to the property in the past six years. Mr Lemon was struck by a van last July while trying to cut a hedge because there is no longer a verge to stand on.
Dr Leinster's first report was sent to DRD officials in July 2012.
In June 2013 the Lemons were sent a report compiled by an engineer within Road Service's highway structures unit.
It acknowledges the gabions and sheet piles encroach under the road but claims the road was reconstructed over them to its previous line, and has been running over them for many years.
It also claims that traffic tends to keep out from the edge of the road to "a similar line as before". However, it concedes traffic can "run closer to the slope and encroach further over the sheet piles and the gabions than before."
The report also attempts to ease concern about the failure of the gabion cages.
Dr Leinster produced a second report in June 2014, which describes DRD's claim that the road was reconstructed to a previous line over the gabions as "very confusing, contradictory and incorrect".
His proposed solution is a retaining wall with a system to stop vehicles crashing on to the Lemons' property.
The Belfast Telegraph contacted the Department of Regional Development about the delay in responding to a second report commissioned by Alan and Elizabeth Lemon last July. Eight months on, they are still waiting for a response. A spokesperson said: "TransportNI is currently considering the report and are looking at a number of options to progress this issue and bring it to a conclusion."