The National Roads Authority (NRA) is to begin night-time working on the M50 because, the authority admits, the alternative would be to close the motorway during the day.
The authority, which has previously said its planning permission forbids night-time working, has candidly admitted it now has no other option if it is to complete the scheme while the motorway remains open.
The move is likely to anger anti-roads activists who have repeatedly criticised the State's road building programme.
The authority told The Irish Timesyesterday that it had examined its "permit" from An Bord Pleanála and it believes that certain works which are a distance from local housing and which are not among the more noisy elements of motorway construction can be accommodated.
The authority intends to put in minor diversions including directing routing traffic up and over junctions while it carries out works which include the installation of precast concrete sections at night.
This is similar to work undertaken at night last Christmas in the vicinity of the M50/N4 (Lucan) interchange, during which the mainline motorway was closed for a few hours.
But now the NRA is to engage in what a spokesman described as the movement of "massive precast concrete, sheet piling and decking" which he also said created "low impact noise," during the night.
"This is within the permission in the permit. There is nothing else we can do. It will involve closing the mainline at night. We can't close the M50 during the day," said the spokesman.
The NRA has previously limited almost all work to the hours between 7am and 7pm from Monday to Saturday, and maintained noise levels within international standards because these were the standards detailed in its environmental impact assessment which was considered by An Bord Pleanála before it approved the project.
Just last month the NRA announced the start of a system of diversions for traffic using the Red Cow Interchange. However, while this initially went well, an escalation of the work on the interchange and the consequent expansion of the diversions, saw sudden and very severe traffic delays on the first morning of operation.
While things have improved with Garda monitoring of traffic, the NRA now admits that if it is to continue major construction only in the daytime, it would have to consider closing the motorway - something which it says is impossible to contemplate.
It is understood traffic volumes on the M50 have fallen slightly in recent months, due to the road works. Currently about 85,000 vehicles a day use the road, down from a high of about 100,000 before the works started.
At the time the upgrade started, the NRA spokesman said keeping the traffic moving while the upgrade is underway was "similar to carrying out open heart surgery on a man while he is on his way to work".
When completed in 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.
