Riccarton Rd residents say they will see the Dunedin City Council in the Environment Court if they go ahead with plans to upgrade the road, near Mosgiel.
Residents on Riccarton Rd and Dukes Rd, near Mosgiel, were invited to an information evening last week to discuss the council's progress on the plans.
An information sheet given out at the evening said the council was investigating upgrading the two roads to provide a bridle path for pedestrians, cyclists and horse-riders, and to widen the traffic lanes and shoulders.
As the existing legal road was too narrow to provide these facilities, additional land would be required.
The preferred option on Riccarton Rd is to put the bridle path on the western side of the road, with widened, gentle curves.
The curves have been included to reduce the effects on residences, historical buildings and significant trees.
The bridle path construction was likely to be completed within five years and road-widening within 10 to 15 years, the information sheet said.
Riccarton Rd Action Group secretary Glen Munn said residents wanted to see the road made safer by taking the trucks away, not upgrading the road.
"I think it is all a move to shift the state highway from the middle of Mosgiel."
The council would have to change the designation of the road before beginning the upgrade and the action group would be joining with the Riccarton Rd West Safety Society Inc to make a submission against that, Ms Munn said.
"We are saying 'bring it on'. We're going to take it to the environment court. After 10 years, we've just about had enough of them [council]."
Mosgiel Taieri Community Board chairman Barry Barbour, who attended the information evening, said a "large majority" of people seemed to be happy with the plans.
However there was "still an undercurrent of people thinking it is being done to turn it into State Highway 87", he said.
"There are no plans in place from Transit, or anywhere, that there are any thoughts of shifting State Highway 87 out of Mosgiel."
The bridle path could be completed within three years, but the council was allowing a couple of years for any potential court action, he said.
The information sheet said council staff would consider comments from affected residents and refine the options. Each property owner directly affected by the proposals will be contacted by council.
The road upgrades are part of the Mosgiel arterial routes plan, which also includes the Centre St-Carncross St extension to connect Hagart Alexander Dr to Dukes Rd.
