The National Roads Authority (NRA) has insisted the "rich historical and archaeological heritage" of Co Meath figured very strongly in selecting a route for the €800 million M3 motorway.
However, in response to queries from The Irish Times, the NRA said one of the route options studied, which would have been less damaging to this heritage, had "serious drawbacks in terms of its ability to serve traffic demand" as well as impacts on communities and the environment.
"The NRA and its local authority partners do not have the luxury of selecting and planning routes on the basis of a single criterion. To do so would surely lead to allegations of being in breach of the EU Environmental Impact Assessment Directive," it said.
As required by this directive, the environmental impacts of the proposed M3 - which it described as a "much-neeeded scheme" - had been "comprehensively assessed" in the environmental impact statement, which was published in March 2002.
Furthermore, the 28-day oral hearing conducted by An Bord Pleanála in August and September 2002 was one of the longest in the history of the State and "afforded full opportunity to the public and interested parties to debate and examine all issues of concern".
The scheme was approved by the appeals board in August 2003 after the planning inspector who conducted the hearing concluded that the proposed route "would not have a significant impact on the archaeological landscape associated with the Hill of Tara".
The NRA said both it and Meath County Council were "fully satisfied that the route chosen and subsequently approved by An Bord Pleanála after a lengthy planning process is the most appropriate route having regard to the full range of environmental, engineering and economic factors".
It said the fact that only two sites listed in the Record of Monuments and Places would be impacted directly along the entire 60 km route was "a remarkable achievement in road planning especially when one considers the landscape through which the proposed road passes".
Test trenching, which involves the mechanical excavation of two metre-wide trenches located 20 metres apart along the entire route, was now being carried out under the supervision of qualified archaeologists following a series of geophysical surveys.
"All archaeological investigations being carried out on the M3 are being done in accordance with licences issued by the Department of Environment, Heritage and Local Government following consultation with the National Museum of Ireland," the NRA said. The agency said the Department of Environment, Heritage and Local Government and the National Museum of Ireland will be informed of the test trenching results and consulted on what further methods might be employed to satisfy their requirements on archaeology.
The NRA said current traffic volumes on the N3, which range from 11,000 vehicles per day between Navan and Kells to 22,000-plus between Blackbull and Clonee, were in excess of its capacity as a two-lane road without hard shoulders for much of its length. It said traffic on the N3 experiences tailbacks, particularly because it passes through the middle of Kells, Navan and Dunshaughlin.
The 1998 National Road Needs Study recommended developing the N3 from Clonee to Kells to dual-carriageway standard, with by-passes of the three towns along its route. According to the NRA, the current plan "is in line with this recommendation".
Asked to explain why a dual-carriageway on the existing route was replaced by a new greenfield motorway, it said the 1998 study was "only one input" into the National Development Plan 2000-2006, which also considered broader policy issues including regional development.
Regarding the N2, just 12 km east of the N3, the NRA said its strategy was to provide a high-quality dual- carriageway from the M50 to Ashbourne, incorporating a by-pass of the town. This project is under construction costing €207 million.
