South Dublin County Council and the Railway Procurement Agency (RPA) will this morning announce plans to separate the Luas from other road traffic at the Red Cow interchange in west Dublin.
The separation of trams from other road vehicles is being undertaken as part of the redevelopment to near "free flow" status of the Red Cow and the general upgrade of the M50.
Trams and other vehicles have been sharing road space at the interchange largely without incident since the tramway opened in September 2004.
This was despite initial scepticism - notably on the part of former minister for transport Séamus Brennan, who suggested putting the trams "on stilts".
RPA spokesman Tom Manning said yesterday that moving the Luas tracks would not involve any interruption to tram traffic.
New rail tracks would be in place before the route was moved and there would be just one move, with no intermittent stages, he maintained.
Currently there are in the region of 90,000 vehicles a day on the M50, and about 70,000 vehicles a day on the M7. The frequency of trams is one every 5½ minutes in each direction during peak times.
Mr Manning declined to be specific on how the separation would be achieved at a number of points where road space is shared.
These points include the southbound carriageway of the Naas Road where trams cross from the central median; the southbound on ramp to the M50 where trams cross to the Luas bridge; and the northbound off ramp from the M50, where trams coming off the Luas bridge cross to the Belgard depot.
However, it is expected that disruption for motorists during the rebuilding of the junction will be more severe than that so far experienced on the M50, as part of the motorway upgrade.
It is understood diversions will include some of the Luas park-and-ride depot at Belgard being utilised by diverted traffic from the interchange.
Diversions on the "mainline" motorway will also be more complex than so far experienced, as the construction site for the upgrade moves to the extreme left lanes of both sides of the motorway.
Traffic will move into the central section of the motorway as work gets under way on the addition of a third main lane and an "auxiliary" lane between junctions.
South Dublin County Council is expected to launch a publicity campaign this morning advising motorists of the changes.
A spokeswoman for the council said maps will be provided and she reminded motorists that speed cameras have recently been installed on the M50 between Ballymount and the N4 (Lucan) junction.
