The number of "two plus one" roads to be built as part of the State's road-building programme is to be reconsidered in favour of full dual-carriageways.
The "two plus one" roads announced in 2004 involve two lanes in one direction and one lane in the opposite direction. The two-lane section alternates every two kilometres to allow access to a safe overtaking lane.
The scheme, used extensively in Sweden, is credited with reducing the number of head-on collisions.
Four schemes were initially identified: the N2 Clontibret to Castleblayney road in Co Monaghan; the N4 Dromod to Roosky in Co Leitrim; the N20 Rathduff to Mallow in Co Cork; and the N15 Ballybofey to Stranorlar in Co Donegal.
The National Roads Authority (NRA) later added the Adare bypass in Co Limerick on the N21 and the Tuam bypass on the N17.
However, The Irish Times has been told that the Department of Transport and the NRA were reconsidering the implementation of the scheme in advance of the sod-turning by Minister of State Pat the Cope Gallagher on the Dromod/Roosky bypass last Friday.
While it was accepted that the "two plus one" roads were substantially safer in terms of fatal accidents than single-carriageway roads, the key issue was whether it made more financial sense to build full dual-carriageways as opposed to upgrading the roads later.
It was decided that the volume of traffic on the Dromod to Roosky road would not warrant an upgrade to dual-carriageway in the medium term. However, other "two plus one" roads are to be reviewed in the light of traffic projections.
Disadvantages associated with the "two plus one" roads include the use of a safety barrier to separate traffic. It is believed Irish motorists are unfamiliar with safety barriers on single-carriageway roads, and experience in Sweden has shown that the presence of such safety barriers slightly increases the number of minor accidents.
In addition, property owners along "two plus one" roads, as well as pedestrians and cyclists, will have to face the same levels of disturbance as those living beside dual-carriageways, travelling longer distances to cross the roadway.
The Irish Times understands that the NRA will review each of the "two plus one" roads based on the predicted traffic volumes and the likely timescale for upgrading the road to full dual-carriageway.
r Minister for Transport Martin Cullen will this morning open a Mitchelstown relief road four months ahead of schedule and within the budget of €10 million. It is designed to alleviate traffic in the town before the opening of the Fermoy bypass in December.
The relief road will leave the existing N8 just north of Cahir Hill, crossing the main Mitchelstown to Limerick road at a roundabout behind the Firgrove Hotel. It will rejoin the existing N8 a mile south of the town.
