A five-year roadworks programme to facilitate traffic approaching Dublin from Waterford, Cork, Limerick and Galway will result in just one "free-flow" interchange out of 14 scheduled for construction or rebuilding.
The construction work began at 9 p.m last night with the start of a scheme to add a third lane and build four new interchanges on the Naas dual carriageway. That scheme is to be followed by overlapping schemes on the M50 involving the addition of a third lane and rebuilding of a further 10 interchanges.
In total the work will cost more than €1.1 billion. During construction speed limits will be reduced to 40 m.p.h. on a phased basis across the motorway network in Dublin and Kildare. The potential traffic disruption has prompted the National Roads Authority (NRA) to offer financial incentives to contractors to work at night, off-peak daytimes and at weekends.
The N7 Naas dual carriageway scheme alone will affect traffic approaching the capital from Waterford, Cork and Limerick. The volume of traffic on the N7 near Dublin is currently about 70,000 vehicles a day approaching the M50 Red Cow interchange. It is the State's second-busiest road.
Work on adding the third lane will continue until mid-2006. But about one year before that scheme is completed, work will begin on widening the Red Cow interchange to the N4 stretch of the M50. And about a year or less after that scheme starts, work will begin on widening the M50 between the airport junction and Sandyford in south County Dublin. The M50 is the State's busiest road with up to 100,000 vehicles a day crossing the N4 Palmerstown junction with the Galway road.
However, the NRA said yesterday that while only one interchange, the N4/M50, would be completely "free-flow", a further four would have major alterations to make them "virtually free-flow".
The spokesman, Mr Michael Egan, said that on five of the proposed interchanges many "motorway-to-motorway" journeys would be free-flow while turns onto surrounding, radial roads into the city would meet traffic lights. For example, he said, traffic coming south on the M1 motorway from Drogheda would be able to join the M50 without meeting a traffic light or roundabout. He also said that while there were 16 sets of traffic lights in the immediate environs of the Red Cow interchange the rebuilding scheme would reduce the number to just one. The separation of traffic caused by the design of the new interchanges would also allow increased speeds and greater route capacity.
"While it's true to say that Palmerstown (the N4 junction) is the only full-blown free-flow interchange there will be virtual free flow on interchanges with the M1, N2, N3 and N7."
He said the NRA had never promised fully free-flowing junctions across the network.
