SOME 30,000 vehicles a day are expected to use the Northern Cross motorway almost as soon as Brendan Howlin cuts the red ribbon near Blanchardstown today. According to the National Roads Authority, this will "bring great relief to the north city area", ending numerous rat runs through its residential roads.
Mr Michael Tobin, the NRA's chief executive, said he was "cocka hoop" about the completion of the motorway, which is the authority's biggest project so far.
The Northern Cross, built at a cost of £71 million, is the second major element of the "C-ring" - or M50, as it is officially designated - to be put in place over the past six years. The Western Parkway, including the West Link toll bridge, was the first phase of the overall route and has been in operation since 1990.
The Southern Cross, which would be the final phase of the M50, has been delayed for almost three years by legal challenges from objectors, but the NRA hopes that the last of these will be settled out of court within the next two weeks. This would clear the way for tenders to be advertised and work to start early next year.
The NRA emphatically denied a claim by Dublin Chamber of Commerce that the Northern Cross, which links Blanchardstown with the Airport motorway, has been "finished for months" and that its opening was delayed merely to deny the main contractors, Walls Tarmac, an early completion bonus. Mr Tobin said this was "nonsense".
Mr Noel Carroll, the chamber's chief executive, maintained that the motorway was actually finished six months ago, apart from such peripheral work as planting shrubbery and erecting gantries.
According to Mr Tobin, the 11 kilometre route has been finished "at least two months ahead of schedule", as the original deadline was next February. The past two months were spent "putting up lights, gantries for direction signs, chevron markings for entries to roundabouts and completing a slip road linking it with the M1 motorway."
Still to come is a £7 million non motorway extension from the M1 interchange at Turnapin Lane to the Malahide Road, which is scheduled for completion next July. But even as it stands, the two completed sections of the C ring will link up the M1, the N2, N3, N4, N7 and N81 national primary routes for the first time.
It is tailor made, therefore, for trucks travelling from, say, Drogheda port to one of the industrial estates in west Dublin or for anyone coming from the Cork direction who wants to get to Belfast without having to go through the city centre. However, this type of traffic is likely to represent only a small proportion of the M50 total.
Mr Mick Foster, the NRA's programme planning manager, said he did not foresee a "capacity problem" at interchanges on the route, such as the major difficulties which have arisen at the roundabout linking the M50 with the Naas Road at the Red Cow Inn. All of the major Northern Cross interchanges were linked with major roads which had been upgraded in recent years.
The most spectacular interchange is at the junction of the M50 with the new N3 Navan road at Blanchardstown. Three decks high, it has a roundabout on top and the motorway below, with both the Sligo railway line and the Royal Canal running through the middle on viaducts. It is almost designed to show off the power of engineering.
Mr Tobin said the NRA's best estimate of the volume of traffic using the Northern Cross from its inception would be around 30,000 vehicles a day. This contrasts with a figure of 11,500 for the Western Parkway when it was finally finished in 1991 - though the volume of traffic crossing the West Link bridge has since climbed to 26,500 vehicles per day.
With traffic in Dublin growing at a rate that greatly outstrips projections, it is now generally accepted that the M50 will be "at capacity - and perhaps even congested - as soon as the Southern Cross is completed in three years' time, just like London's M25 orbital motorway. There is provision, however, to upgrade it from four lanes to six.
But even after the Southern Cross comes on stream, the impact of the entire C ring will be relatively marginal in terms of traffic volumes in the city centre. Indeed, it has been estimated that the M50 will only reduce these volumes by around 5 per cent. Thus, in no sense can it be seen as a panacea for relieving Dublin's traffic congestion.
The NRA is currently involved in discussions with the Dublin Transportation Office on the thorny, and politically sensitive, issue of tolling. Its case for imposing tolls is based on protecting the primary purpose of the M50 as a bypass of the city for long distance traffic, rather than a route catering for car hopping between shopping centres.
