10 February 2017 Headford Road Roundabout – where to from here?

We move on to review the design options being considered in the latest consultation on replacing the Headford Road (Kirwan) Roundabout with traffic lights. (Please see preceding article for a submission template). This discussion is based on the latest consultation document. The document sets out 6 design options for consideration. However three of the options involve building new slip roads (Options labelled 2a, 2b 2d). This means they can be dismissed out of hand as unsuitable for an urban area.

This leaves three options that merit further consideration.

Option 1

Kirwan Roundabout replaced with a 5 arm signalised junction.

Option 3A

Kirwan Roundabout will be replaced with a 4-arm signalised junction.
Coolagh Road will no longer be accessed from the Kirwan junction.
Coolagh Road will be diverted southwards through the ‘Circus Field’ to form a 4-arm signalised junction with the N6 Headford Road and Dunnes Stores Entrance.
Dunnes Stores Entrance will be moved northwards to facilitate a 4-arm signalised junction.

Option 3B

Kirwan Roundabout will be replaced with a 4-arm signalised junction. Coolagh Road will no longer be accessed from the Kirwan junction.
Coolagh Road will be diverted northwards to the front of the Menlo Park Hotel to form a 3-‐arm signalised junction on the N84 Headford Road.
A left slip lane allowing traffic to access Coolagh Road from the N6 Headford Road is being considered as part of this option.

Discussion: Option 1 (5 arm traffic signals)

Screen grab of Option 1 from the consultation document

One of the complications of Option 1 is that it is a five-arm junction. This is difficult to achieve and is technically challenging. If a way could be found to remove one arm then this would simplify the junction design. The Sandy Road arm is an obvious candidate since the alignment is difficult relative to the other arms.

The question is how to maintain access from the West to Liosbán. There are already three pockets of state or semi-state land that provide a potential route corridor.

1. The City Council Yard at Liosbán (Yellow boundary below)
2. The County Council Yard at Liosbán (Orange boundary below)
3. The ESB land between Sean Mulvoy Road and Sandy Road (Green boundary below)

Google maps extract showing state/semi-state properties at Liosbán and Sean Mulvoy Rd

These lands provide two potential corridors linking Liosbán to the Sean Mulvoy Road. If this corridor was developed it would also allow traffic from other properties on Sandy Road to avoid Cemetery Cross. It is likely that this route would attract rat running by other traffic trying to avoid Cemetery Cross via Liosbán. This reinforces the identified need to close Liosbán to through-traffic and maintain the internal roads as a resource for people with business in the estate.

Google maps extract showing alternative access corridors using state/semi-state properties at Liosbán and Sean Mulvoy Rd

Discussion: Options 3A and 3B (Coolagh Road diversion)

Options 3A and 3B involve diverting the Coolagh Road to other locations. One north of the current junction and one south. One point of concern is the designers also appear to be threatening to use another slip road with option 3B which would defeat the underlying purpose of removing the roundabout.

Screen grab of Option 3A from the current consultation document.

Screen grab of Option 3B from the current consultation document.

It is likely that neither of these options – by itself – will be satisfactory for stakeholders on the Coolagh road side of the junction. There was prominent opposition from this area to the last set of proposals. In our analysis a solution is to combine both options. It might be these could be linked to Coolagh road using a roundabout based on Dutch (not British) designs. These are designed to slow motor traffic and maintain access for cyclists and pedestrians. This could also link with Dun na Coiribe to provide a four-way junction serving both Dun na Coiribe and the Dunnes retail park. This option might still attract rat-running via Menlo and the Dyke Road. Again the obvious solution is to block the Dyke Road to through traffic and actively engineer the roads in Menlo village to discourage through-traffic.