Plans to put the Luas line "on stilts" at Dublin's Red Cow roundabout are likely to be scrapped in favour of a new €500 million deal between the private company, National Toll Roads (NTR), and the National Roads Authority (NRA), the Minister for Transport, Mr Brennan, announced yesterday.
The deal involves the rebuilding of the Red Cow interchange without the roundabout, and the addition of another motorway lane on the M50, between Tallaght and the Dublin Airport junction.
The Minister said he was "strongly of the view" that the deal should go ahead, having seen computer predictions and a scale model depiction of the impact of the changes on the Luas line.
However, he said that the Red Cow interchange should be done first - "in year one of the project" - before the other aspects of the deal were implemented.
The Minister said he has "asked NTR to put it all in writing", and if that is good enough "then we have a deal". The Minister said the project was to be driven with some urgency and NTR had told him work could begin within 18 months if they had a decision from him in the next four weeks.
Involved is a complete redesign of the M50 junction with the N7 - the junction which joins the State's busiest and second-busiest roads. The M50 at the Red Cow is now carrying up to 100,000 vehicles a day, while the N7 is carrying about 70,000. Congestion in the area is chronic.
Under the proposed scheme, there would be "freeflow" of traffic using "clover leaf" spirals and new slip roads - "the spaghetti junction" option - according to the Minister.
"It is the best solution. If they can bring it forward and say to me it will take 50 or 70 per cent of traffic out of crossing the Luas line, then I will go for it."
Mr Brennan added: "The NRA says it is very doable".
It is understood NTR, which recently completed the second west link bridge at a cost of about €23 million, is seeking a longer concession on its west link toll franchise in return for building the new junction and M50 improvements.
The NRA initially envisaged rebuilding all the junctions along the M40 and adding a third lane between the airport and Sandyford in south county Dublin.
The Minister also revealed that he has not come to a final decision on the clearance height of the Dublin Port Tunnel. The first report from Atkins consultants suggested that the tunnel clearance height might be amended to take lorries above the 4.65 metre standard at a cost of just €20 million, without significantly delaying the project.
