South Dublin County Council has "no intention" of closing down the M50 motorway during its €1 billion upgrade, now under way, according to the council's director of transportation, Frank Coffey.
He made the statement at a press briefing yesterday on the traffic management arrangements being implemented from tomorrow night to facilitate installation of a new overbridge at the N4/M50 interchange.
However, while 24 pre-cast concrete beams for the overbridge are lifted into place, "local diversions" will apply from 10pm tomorrow to 7am on Saturday, 10pm on Saturday to 8am on Sunday and 10pm to 6am on both Monday and Tuesday nights.
Tomorrow night will involve closing the M50 southbound lanes at the N4 interchange, while the northbound lanes will be closed on Monday and Tuesday nights and both directions will be closed simultaneously on Saturday night/Sunday morning.
Hugh Creegan, head of programme management for the National Roads Authority (NRA), said traffic on the motorway during the relevant times would be diverted on to the adjacent slip road so it could maintain access to the M50.
Motorists would get a bonus from January 15th when the first permanent free-flow arrangement with no traffic lights opens at the interchange, via the slip road leading from the N4 (eastbound) to the M50 (northbound).
Another new traffic management phase early in the new year will also remove the traffic lights for eastbound trips through the interchange, heading towards the city centre. Mr Coffey said this would bring "considerable benefits".
However, motorists travelling north on the M50 and using the N4 interchange to turn right towards the city will first have to turn left and use the nearby Liffey Valley junction to make a U-turn in the direction of the city.
Similar diversions are expected to occur under the bridges of the Ballymount and Red Cow interchanges as work progresses on the M50 upgrade, with a view to having the western section of it completed by mid-2008.
John Glynn, project engineer with contractors Siac-Ferrovial, said traffic impacts during the upgrade were unavoidable, but good traffic planning and advance notice in the media would minimise the level of disruption.
He said work was progressing well on Contract 1, which is worth €244 million. This involves widening the M50 to six lanes between the N4 and Ballymount interchanges and upgrading the two interchanges to make them free-flowing.
Before these works are completed, it is expected that work will start on reconfiguring the interchanges on both the northern and southern sections of the M50. However, these sections are not due to be completed until 2010.
By then, there will be three lanes in each direction on the main route of the motorway, an additional fourth lane linking junctions, barrier-free tolling at the Westlink bridge and free-flow traffic movements at major junctions.
Mr Cregan said the overall effect would be to double the capacity of the M50 from a current average flow of 90,000 vehicles per day. But he denied that the motorway would be as congested as it is now when the project is finished.
His view was endorsed by Mr Coffey, who said that "a lot of public transport schemes are due to be delivered" under the Government's €34.4 billion Transport 21 programme, and these would take some pressure off the M50. A 60km speed limit will apply for the duration of the works between the Ballymount and N4 interchanges. Two lanes will be open in each direction between 6am and 10pm every day, while diversions would apply outside those hours.
Details will be announced in advance in the national and local media and on the NRA/South Dublin County Council website, www.m50.ie
