Drivers are being warned that as part of the M50 upgrade there will be new diversions in force near the Red Cow roundabout from tomorrow.
At a news conference, a project spokesman said that the Luas is to be separated from road traffic at the roundabout and that the upgrade was now entering a critical phase.
The Luas track will no longer cross the traffic lanes of the roundabout when the phase is completed.
The roundabout will also become freeflow with all traffic lights being removed.
It is hoped that this will be completed in about one year.
Westbound traffic at the N7 Red Cow Interchange will be diverted onto a new carriageway from tomorrow.
In two weeks inbound traffic will be diverted to the existing outbound lane.
Motorists are being reassured that all diversions will be well signposted.
A leaflet detailing the diversions and the changes being made to the M50 will be made available to motorists from tomorrow.
