Roughan & O’Donovan N14 / N15 to A5 Link Consulting Engineers Environmental Impact Statement – Volume 1 Chapter 5 Traffic & Transport Impacts Ref: 10.152 July 2011 Roughan & O’Donovan N14/N15 to A5 Link Consulting Engineers Environmental Impact Statement – Volume 1 Chapter 5 Traffic and Transport Impacts 5.1 General This chapter provides an overview of the traffic and transport impact assessment undertaken for the N14/N15 to A5 Link project. This includes the following activities: Examine the existing traffic conditions and road network; Estimate future traffic growth; Appraise the proposed development; Assess the traffic and transport impacts of the scheme; Determine any mitigation measures required. 5.2 Existing Conditions 5.2.1 Local Road Network The N15 is a National Primary Route that links Sligo in the southwest of the region with Lifford in the north. The N14 is a National Primary Route that links Letterkenny and Lifford. Both the N14 and N15 connect to the A5 at Lifford which runs from Derry through Strabane and continues south to the border at Aughnacloy where it becomes the N2 National Primary Road connecting to Dublin. The existing route between the A5 and the N14 / N15 is via the N14 / N15 Roundabout in Lifford before crossing the River Foyle and becoming the A38 for a short 600m stretch before connecting to the A5 Roundabout west of Strabane Town Centre. A5 Western Transport Corridor (WTC) Scheme starts at New Buildings approximately 5 km south of Derry and runs for a distance of 85km south to the border, close to the village of Aughnacloy. The A5 WTC would feed into the N2 at the Moy Bridge border crossing. Together the A5 and N2 would provide a strategic link between Dublin and the North West / County Donegal. At Strabane the proposed A5 WTC Scheme would skirt the western edge of the urban area with junctions to the west, south-west and south of the town. The junction to the south-west allows for the proposed N14 / N15 to A5 Link. 5.2.2 Existing Traffic The N15 single carriageway route has a base AADT (Annual Average Daily Traffic) flow of 8,900 west of Lifford Roundabout and an AADT of 5,700 on the southern approach to Lifford, on the Churchtown / Castlefinn Road. The N14 is a single carriage way that carries an AADT of 11,800 north of Lifford Roundabout. The existing traffic on the Lifford to Strabane link road connecting the N14 /N15 to the A5 currently carries an AADT of 16,000. Ref: 10.152 July 2011 Page 5/1 Roughan & O’Donovan N14/N15 to A5 Link Consulting Engineers Environmental Impact Statement – Volume 1 5.2.3 Road Accidents Accident statistics obtained from the Road Safety Authority were examined for the section of the N15 at the tie-ins of the proposed bridge link and up to and including the N14 junction in Lifford for the period 1998 to 2008. Accident data has not been examined for the east side of the River Finn or Foyle, as this road network will be significantly enhanced by the proposed A5 Western Transport Corridor Scheme. For this 10 year period (1998 – 2008) the accidents statistics, as shown on Figure 5.1, Volume 2 are as follows: 17 total number of accidents involving either injuries or fatalities and excluding material damage incidents. A breakdown of these is as follows; 0 no. fatal accidents; 1 no. serious injury accident; 16 minor injury accidents. 5.3 Proposed Development 5.3.1 Description of the Proposed Scheme The N14/N15 to A5 Link Scheme involves the redesign of a road linking the A5 Western Transport Corridor in Co. Tyrone, Northern Ireland to the existing N15 in Co. Donegal, Republic of Ireland. The proposed road link is defined as a “rural “scheme where pedestrian activity is not envisaged, where it is noted that no dedicated pedestrian or cycle facilities are to be provided on the A5 WTC scheme. The existing Lifford to Strabane link road includes footpaths and street lighting, where the proposed scheme will divert significant volumes of traffic, thereby improving the existing pedestrian and cyclist environment. 5.3.2 Future Road Network There are a number of road upgrade proposals in the region as follows: N14 / N15 to A5 WTC Link Road; N15 Lifford – Stranorlar – Ballybofey; N13 / N15 Ballybofey and Stranorlar Bypass; N14 Letterkenny to Lifford Scheme; and A5 Western Transport Corridor Scheme, as described in section 5.2 above. The proposed N15 to Stranorlar scheme comprises an offline upgrade of the N15 to dual carriageway standard. To the west, the scheme ties into Stranorlar Roundabout on the proposed N13 / N15 Ballybofey and Stranorlar bypass. The proposed N13 / N15 Ballybofey and Stranorlar bypass scheme will generally be a dual carriageway passing to the east of the twin towns of Ballybofey and Stanorlar. The scheme ties in to the existing N15 approximately 6.1km south of the Crappry Road junction to the southwest of Ballybofey. The proposed N14 Letterkenny to Lifford scheme will generally be a dual carriageway. At its southern extent, the scheme will tie into a new roundabout adjacent to the N15 at Coneyburrow. Ref: 10.152 July 2011 Page 5/2 Roughan & O’Donovan N14/N15 to A5 Link Consulting Engineers Environmental Impact Statement – Volume 1 5.4 Traffic Forecasts The N13, N14 & N15 Traffic Model Study, September 2010 was prepared by Jacobs Engineering for Donegal County Council and the NRA to assess the N13, N14 and N15 Road Schemes including: N14 / N15 to A5 Link Road; N15 Lifford – Stranorlar – Ballybofey; N13 / N15 Ballybofey and Stranorlar Bypass; N14 Letterkenny to Lifford Scheme; and A5 Western Transport Corridor Scheme. Its principal purpose was to provide traffic data extracted from the future year models with the aim of informing the design, environment and economic assessments, including the River Finn Link. Traffic growth between base year 2010 and design year 2030 used in the forecasts presented within the Jacobs report indicates an average increase of 50%, 62% and 28% of car, Lights Goods Vehicle and Medium Goods Vehicle and Heavy Goods Vehicle journeys respectively in the Republic of Ireland and Northern Ireland zones of the scheme. The 2030 Design Year Average Annual Daily Traffic (AADT) for the proposed N14 / N15 to A5 Link Road has been assessed for a number of scenarios. The ‘Do Minimum’ scenario assessed includes the existing road network plus the completion of the A5 Western Transportation Corridor. The ‘Do Something’ scenario assessed includes the ‘Do Minimum’ network as described above plus the construction of the N14 / N15 to A5 Link. A summary of the results at low, medium and high traffic growth scenarios is presented in Tables 5.1 – 5.3 below: Table 5.1: Traffic Forecasts AADT – Low Growth Scenario Traffic Forecast Scenario / 2010 Base 2030 Do 2030 Do Location Year Minimum Something A38 / N14 Lifford to Strabane 16,000 21,600 11,700 N15 southwest of Lifford Roundabout 8,900 12,000 13,100 N15 Castlefinn to Churchtown 5,700 8,400 10,700 N14 Northwest of Lifford Roundabout 11,800 15,700 15,800 A5 WTC north of Proposed Link - 20,900 19,700 Proposed N14/N15 – A5 Link Road - - 14,100 Ref: 10.152 July 2011 Page 5/3 Roughan & O’Donovan N14/N15 to A5 Link Consulting Engineers Environmental Impact Statement – Volume 1 Table 5.2: Traffic Forecasts AADT – Medium Growth Scenario Traffic Forecast Scenario / 2010 Base 2030 Do 2030 Do Location Year Minimum Something A38 / N14 Lifford to Strabane 16,000 22,100 11,900 N15 southwest of Lifford Roundabout 8,900 12,400 13,700 N15 Castlefinn to Churchtown 5,700 8,700 11,100 N14 Northwest of Lifford Roundabout 11,800 16,100 16,300 A5 WTC north of Proposed Link - 21,100 19,900 Proposed N14/N15 – A5 Link Road - - 14,500 Table 5.3: Traffic Forecasts AADT – High Growth Scenario Traffic Forecast Scenario / 2010 Base 2030 Do 2030 Do Location Year Minimum Something A38 / N14 Lifford to Strabane 16,000 24,400 12,900 N15 southwest of Lifford Roundabout 8,900 14,400 16,000 N15 Castlefinn to Churchtown 5,700 10,000 12,800 N14 West of Lifford Roundabout 11,800 18,000 18,100 A5 WTC north of Proposed Link - 22,200 20,600 Proposed N14/N15 – A5 Link Road - - 16,400 The 2010 base year traffic on the A38 / N14 Lifford to Strabane Link is 16,000 AADT. The traffic using this link in the high growth scenario is predicted to increase to 24,400 AADT in the 2030 Design Year Do Minimum Scenario (existing road network plus the A5 Western Transportation Corridor). With the construction of the of the N14/N15 to A5 Link bridge, Do Something Scenario, traffic using the A38 / N14 Lifford to Strabane Link is predicted, in the high growth scenario, to be reduced to 12,900 AADT in the 2030 design year. This is a reduction of 54% in the AADT and will significantly reduce congestion on the link bridge which directly connects Lifford and Strabane. The 2030 design year traffic volumes for the Do Minimum and Do Something high growth scenarios are shown on Figure 5.2, Volume 2. 5.5 Traffic Assessment The AM and Inter Peak hour turning movements either side of the proposed N14/ N15 to A5 Link Road were analysed for the Design Year using ARCADY, an industry accepted traffic analysis software program developed by TRL. ARCADY is used to assess predicting capacities, queue lengths and delays at individual roundabouts. The layout options of the junctions at the tie-ins either side of the N14 / N15 to A5 Link Road is indicated on Figures 3.1 and 3.2, Volume 2.