The National Roads Authority (NRA) has said it is powerless to include night-time and Sunday working on the upgrade of the M50 motorway in Dublin, because such work is forbidden under the terms of its planning permission.
Construction activity will be limited to the hours between 7am and 7pm from Monday to Saturday, the authority said.
The restriction is largely because of the noise levels at nearby housing, which are governed by international standards and which were incorporated in the environmental impact assessment and approved by Bord Pleanála.
But the NRA said work on the first phase of the upgrade - the addition of a third lane and the redesign of the junctions to free-flow or near-free-flow status - was going well.
Spokesman for the authority Seán O'Neill said a major report would likely be made this week in relation to progress on the route.
The Irish Times understands the report relates to arrangements for the completion of work in the central median of the motorway between the Ballymount and N4 junctions.
Following the completion, construction work will move to the extreme left-hand carriageways, while traffic - currently about 90,000 vehicles a day from a high of about 100,000 before the works started - will move to the new central section.
Keeping the traffic moving while the upgrade is under way was described by Mr O'Neill as "similar to carrying out open heart surgery on a man while he is on his way to work".
The switch in traffic lanes will also allow the contractor Siac Ferrovial to get the reconstruction of the Ballymount and Red Cow junctions under way in earnest and to progress the free-flow arrangements on the N4 junction.
It is also expected that a major publicity campaign will be launched to advise motorists of the repositioning of traffic lanes.
Mr O'Neill said yesterday that the authority was anxious to get the work completed as quickly as possible but had to take account of the now urban nature of the location, and of the amenity of those living in nearby houses.
When completed by mid-2008, each side of the motorway between the Ballymount and N4 junctions will have three main lanes and an "auxiliary" lane between junctions. The junctions will also have been upgraded to free-flow or near-free-flow status.
Phase two comprises the widening of the remainder of the M50, other than the West-Link section between the Lucan and Blanchardstown junctions, and the upgrade of the other interchanges between the airport and Sandyford.
Phase three is the widening of the West-Link section between the Lucan and Blanchardstown junctions.
