In the event of the proposed €90m upgrade being approved, it would signal the commencement of other major projects in the region.
To date, traffic congestion has been a setback to new projects.
Cork County Council’s senior planner, Andrew Hind, said the improvement plan was vital for Cork.
He referred to the Port of Cork’s plans to build a deep-water terminal in Ringaskiddy which were previously rejected by An Bord Pleanála amid concerns the extra heavy goods traffic generated would prove too much for the already over-capacity junction.
Mr Hind said he wanted to see a multimillion-euro housing project, proposed by O’Flynn Construction at Dunkettle, proceed. It was rejected by An Bord Pleanála for the same congestion reason.
Mr Hind said the junction upgrade was also vital to the planned science park at Curraheen, and “it’s importance can’t be understated, especially in further developing the East Cork commuter corridor”.
Day two of the oral hearing at the Silver Springs Moran Hotel also heard concerns raised by locals.
Stephen Pearson of North Esk Residents’ Association said he was worried over-development in the area would put homes at risk of flooding.
Another local, Mark Tyrell, said he was concerned the new road layout would increase traffic noise. “Motorists should not be prioritised above the rights of residents,” he said.
Dr Stephen Smyth, on behalf of the National Roads Authority, said a “low-noise road surface” would be used, adding that the NRA would not be paying for locals to get double-glazing.
He said there would be some noise during construction and the NRA would use screening to mitigate against it. It will appoint a residents’ liaison officer to deal with such issues.
Patrick Dorgan, solicitor for Punch Industries, Little Island, said the firm had some concerns about the project, especially if it led to flooding which could damage production of its Colour Catcher product.
However, he said that following talks, “they had reached an accommodation” with the NRA.
Around 30 known archaeological sites are dotted around the designated project area, most of which are post-medieval.
NRA experts said they would carry out “test-trenching and metal detector surveys” to establish if there were other sites of interest.
Dr Jervis Good of the National Parks & Wildlife Service made recommendations to An Bord Pleanála inspector Jane Dennehy, which he said would ensure that otters and little egret roosts on the Glashaboy Estuary are protected during construction and thereafter.