COMHAIRLE CONTAE ÁTHA CLIATH THEAS
SOUTH DUBLIN COUNTY COUNCIL

South Dublin County Council Crest

MEETING OF LUCAN / PALMERSTOWN / NORTH CLONDALKIN AREA COMMITTEE

Tuesday, January 23, 2024

MOTION NO.4

MOTION: Councillor S. Moynihan

To ask the Chief Executive to consider what traffic engineering solutions could be put in place at the Castle Road/Ballyowen Road junction to improve traffic flow, including the revision of the sequencing of the lights or inclusion of a roundabout.

REPORT:

The Ballyowen Castle Road junction is very complex traffic light controlled junction.  It incorporates vehicular, cycling and pedestrian movements.  

A traffic signal controlled junction is the most efficient and safe junction layout for all users.  Each travel mode can be accommodated in a phased way which greatly improves the safety for all modes, but particularly for cycling and walking.

This junction is very busy and at peak times it is currently it is going to be at capacity and occasionally over capacity.  However, it terms of junction type and efficiency, the current layout is optimal.  The more modern junction designs would remove the slip roads and this in fact would reduce vehicular capacity of the junction, while making the cycling mode safer.

I have asked our Traffic maintenance contractor to examine the current phase times to see if any adjustments could be made to aid traffic flows.

The changing of the junction to a roundabout would be a backward step.  It would reduce the vehicular efficiency making queue lengths longer.  Timing adjustments on each leg would be removed unless you doubled the land take to make it a traffic light phased roundabout like the airport roundabout. But this measure would make cycling less safe .  It would also make pedestrian movements longer with significantly increased sideways diversion around the roundabout.  You will note that at the airport roundabout there are no cycling and very limited pedestrian movements on one leg of the roundabout.

In summary, the existing junction is the best layout for all modes of travel.  The short term solution is to examine the traffic light phase timings to ensure they are at the optimum configuration. The long term solution is to improve bus services, improve the cycling and pedestrian facilities in order to reduce overall car numbers through this junction.