N56 Letterkenny Relief Road
Last Updated 28/09/11
Introduction
The National Secondary Route N56 links the towns of Donegal in the South West of the County with Letterkenny in the North East via the towns of Mountcharles, Dunkineely, Ardara, Glenties Dungloe, Loughanure, Gweedore, Gortahork, Falcarragh. Dunfanaghy, Creeslough and Kilmacrenan. The N56 enters Letterkenny at Mountaintop. From there it continues until it reaches the Pramerica Roundabout where it turns left onto the recently constructed road serving the IDA Business Park. The N56 then proceeds through a series of priority junctions until it links to the R245 Ramelton Road where it turns right and continues to join with the National Primary Route N14 at the Polestar Roundabout. The regular congestion at the Polestar Roundabout together with the frequent interaction with local traffic, requiring longer distance traffic to yield to local traffic in some cases, results in a relatively low level of service on the N56 within Letterkenny. This is particularly the case during times when traffic flows are at their peak.
The Need for the Project
The existing road that is proposed to be replaced by this scheme can be split into two distinct sections;
- The N14 from the Dry Arch Roundabout to the Port Bridge Roundabout and;
- The N56 from the N14 Polestar Roundabout to the recently constructed N56 IDA road.
The N14 is a 1.4km long four lane undivided road with frequent commercial access points, right turning lanes, at-grade priority junctions and high traffic volumes currently 29,609 AADT. This section is usually heavily congested at peak times with the Polestar Roundabout being particularly problematic.
The N56 is a 1.8km long single carriageway road of varying standard with frequent access (both commercial and residential), two roundabout junctions and three at-grade priority junctions. The volume of existing traffic varies between 7,761 AADT and 17,161 AADT. National road traffic is forced to yield to local traffic at two of the three at-grade priority junctions resulting in congestion at peak times.
At present there are only two existing crossing points of the River Swilly within Letterkenny, one on the N14 and one at Old Town. The bridge at Old Town mainly caters for local traffic movements leaving the N14 bridge to cater for all other traffic. The need for a second bridge for strategic traffic has long been acknowledged.
A traffic model has been prepared for Letterkenny and this model predicts that the N56 Letterkenny Relief Road, by relieving congestion at the N14/N56 Polestar Roundabout and by providing another river crossing, will result in a significant easing of congestion generally throughout Letterkenny.
Description of the Project
The proposed N56 Letterkenny Relief Road extends from the N13/N14 Dry Arch Roundabout to the recently constructed N56 IDA road. It is approx. 2.4 km long and is proposed to replace approx. 3.2 km of existing national road.
There are some significant constraints associated with the project that will need to be considered in a lot of detail at the Preliminary Design stage. These are;
• River Swilly Special Area of Conservation and Natural Heritage Area are located in close proximity.
• Construction on the flood plain of the River Swilly is likely. Flood protection bonds are already in place and it is expected that this project can be designed so as to have a negligible impact on the movement of flood waters.
• There are some very deep sections of soft ground on the eastern side of the River Swilly which will complicate the design of the new bridge.
• This project will involve the construction of a new 100m long river bridge.
Current Status
To date the project has been developed by Donegal County Council staff in the National Roads Design Office in Donegal Town, with specialist consultants being employed as necessary. The Route Selection process has been completed and the Council have approved the Preferred Route at their Meeting on 26th April 2010. The project has not received a funding allocation in 2011 and is on hold until funding becomes available.
Next Steps
The next stage of this project is to develop the preliminary design and assess the environmental impact to allow an application for planning approval to be made to An Bord Pleanála. This is dependent on sufficient funding being available.
Enquiries
Any enquiries should be forwarded to the National Roads Design Office at the Donegal Public Services Centre, Drumlonagher, Donegal Town or telephone (074) 9724500 for the attention of Brendan O’Donnell, Senior Executive Engineer or Mark Gallagher, Assistant Engineer or alternatively e-mail design@dnrdo.ie
Proposed Layout
