From this morning the two northbound lanes on Dublin's M50 will be separated as part of the development work on the motorway.
From 6am the latest diversion between the Red Cow interchange and the N4 Lucan interchange will see northbound traffic divide to allow surface works to continue between the lanes.
The move replicates a similar diversion on the southbound carriageway which was introduced a week ago.
However, South Dublin County Council, which issued and apology to motorists for confusion on that occasion, said "advance signage will be in place, clearly informing motorists of the changed layout" on this occasion.
While two lanes will remain fully available to northbound traffic, motorists wishing to exit at the N4 (Lucan) interchange should use the left-hand lane on passing the Red Cow. The N4 (Lucan) interchange gives access to routes to the western suburbs of Lucan and Palmerstown, and to the west and northwest of Ireland.
Both lanes will still allow traffic to continue north on the M50 towards the airport.
The changes are expected to last six weeks.
Work on this section of the M50 is expected to continue until the middle of next year as part of the plans to add a third lane in each direction, rebuild the interchanges to near freeflow status, and install a "junction to junction" fourth lane for local traffic. Ultimately the enhancements will increase the capacity of the road by 50 per cent between the M50/M1 airport junction and Sandyford.
The construction effort, which the National Roads Authority has described as "open-heart surgery on a man while he is on his way to work", has not been without its difficulties. South Dublin County Council's recent apology was issued after tailbacks reached 13kms.
