11 Traffic Assessment Summary

Home , A5 road (Great Britain), Ballymagorry, Lifford Bridge, Omagh, Strabane

Preferred Options Report Scheme Assessment Report 2

The following sections summarise the work undertaken for the preparation and detailed delivery of the traffic modelling and associated economics.

11.1 Zone System A zone system has been devised for the A5 WTC study in order to define journey trips ends unambiguously across the whole of Northern Ireland and the Republic of Ireland.

The zone system is most detailed within the main population centres along the route of the A5, particularly Londonderry, Strabane and Omagh. The zone system is also at fine level along the inter-urban sections of the A5, and becomes progressively coarser away from the route of the A5.

The zone system in Northern Ireland was established to ensure that zones do not straddle local government (District) boundaries or Parliamentary Constituency boundaries. Furthermore within locations near to the A5 (defined by the Districts of Londonderry, Omagh, Strabane and Dungannon) zones do not straddle Ward boundaries.

Northern Ireland is covered by 337 zones.

In the Republic of Ireland the zone system is most detailed in the counties that border Northern Ireland at either end of the A5 scheme. These are County Monaghan and County Donegal. Within these counties, zones typically contain 2 or 3 medium sized towns. Within the remainder of Republic of Ireland, the zone system generally follows the county boundaries.

The Republic of Ireland comprises 44 zones, giving an overall total of 381 zones for the entire zone system. The zone system is illustrated in Figure 11-1.

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Figure 11-1: Plan showing the distribution of A5 WTC zone system across Northern Ireland and the Republic of Ireland

11.2 Highway Network The A5 WTC model has been based on the CUBE Voyager suite of transport modelling software which is a development from the TRIPS suite. CUBE Voyager includes a sophisticated and user friendly facility for dealing with transport modelling. In particular, it contains a GIS system for the handling and management of highway networks.

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The Northern Ireland Strategic Transport Model (NISTRM) model developed previously for Road Service was used as an initial dataset for model development. This was refined to provide more detail, principally by the addition of further links and junction detail, including:

• Increased number of zones in the A5 area, requiring additional centroid connectors and more detailed network.

• Improved network coverage in urban areas.

• Extended external network to match extended external zones (covering all of Northern Ireland and the Republic of Ireland).

• More network detail in the A5 Study Area.

Network details were obtained from:

• Signal timings - taken from on street observations.

• Lane arrangements and stop line widths - observed on aerial photos and site visits.

• Link types and speed flow curves - allocated using the COBA standards.

In order to verify that the modelled network correctly represented the current base year situation a number of checks have been undertaken, as follows:

• Correct loading of centroids.

• Link length checks.

• Routing through the network.

• Network hierarchy and speed flow definition.

An examination of the Voyager network and zone boundaries confirmed that each zone centroid had been loaded within its geographical zone boundary.

Link lengths were calculated directly within the A5 WTC model using the node coordinates. A sample of link lengths were checked using Mapinfo for comparison with GIS data.

The modelling of traffic routings through the road network has also been checked. These were assessed using the path analysis facility available in Voyager, which displays paths graphically on a map based background. This was used to confirm that routings through the network were logical.

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Further checks were conducted to ensure that modelled link types were consistent with the actual characteristics of each location, (e.g. rural link types outside of towns and urban link types within towns). This ensured that the appropriate speed flow relationships based on COBA 11 were used on each link in the model assignment.

11.3 Modelling Time Periods The model was built using matrices derived from Roadside Interview (RSI) surveys. Each RSI survey was carried out on a single weekday between 7am and 7pm during May and June 2008.

The A5 WTC traffic model includes 3 separate time periods. These are the morning peak, the inter-peak (IP) and the afternoon peak. The exact timings of these modelling periods have been established with reference to the traffic flow profile on the existing A5 through each of the A5 WTC scheme sections.

The daily flow profile for each section indicates that the morning and the afternoon peaks last longer than a single peak hour. For this reason, 2 hour long model time periods were adopted to ensure that the traffic model included traffic travelling just before and just after the main peak. The periods selected were from 7:30am to 9:30am for the morning peak, and between 4pm and 6pm for the afternoon peak. An inter-peak period has been defined as the average hour between 11am and 3pm.

Figure G-1 in Appendix G shows the flow profiles, and indicates the selected model time periods.

11.4 User Classes The traffic model makes use of several user classes in order to differentiate between trips with varying values of time. These user classes are:

• Car – Journey between home and work (“Commute”)

• Car – Employers Business

• Car – Other

• Light Goods Vehicle

• Heavy Goods Vehicle (including Medium Goods Vehicles)

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11.5 Available Data In order to inform the base modelling work the availability and coverage of existing traffic surveys completed in the vicinity of the A5 during the last 5 years were established.

The review identified 3 sources from which RSI data could be utilised (with associated Manual Classified Counts (MCCs) and Automatic Traffic Counts (ATCs). These were situated in the vicinity of:

• Cookstown 2007 1 site

• Lifford 2006 2 sites

• Londonderry 2006 6 sites

Some RSI data was also collected in Omagh in 2004 but as this was a morning survey only, and predated the current A5 Throughpass Stage 3, it has been superseded by specific data collection in 2008.

Additionally, long-term ATC data was obtained from Roads Service for locations across Northern Ireland.

11.6 Data Collection Following the review of available data, a detailed methodology and procurement process was followed to undertake additional surveys. These comprised:

• (two-way) Roadside Interviews

• 31 Automatic Number Plate Recognition (ANPR) Surveys

• 51 Automatic Traffic Counts

• 30 Manual Classified Counts

These surveys were undertaken during Spring 2008 and the locations of available and surveyed RSI surveys are shown on Figure 11-2.

The information summarised in paragraphs 11.5 and 11.6 above is described in further detail within the Traffic Data Collection Report.

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Figure 11-2: Locations of RSI surveys used to Build Trip Matrices for A5WTC Traffic Model

11.7 Data Processing A number of checks were undertaken on the surveyed trip data to ensure accuracy and consistency. Records from previous surveys were also standardised for consistency across all datasets.

11.7.1 Data Checks Trip records for each dataset were initially “cleaned” through a checking process. These checks comprised:

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Logic Check - confirming that responses for various data fields corresponded with expected ranges.

Trip End Check - both trip ends for each record were converted from addresses/postcodes to OSGRs. These were then plotted using a Geographic Information System (GIS) to confirm that each trip would logically pass through the survey location, in the correct direction.

Trip records which did not satisfy these checks were adjusted or eliminated from the expansion processes.

11.7.2 Expansion Process The aim of expansion is to amplify the sample of trips observed to represent all traffic travelling through the survey station in the appropriate time period. In order to expand each record accurately, trips were grouped based upon vehicle type and the time of the journey.

Vehicle types used were:

• Cars and Taxis;

• Larger Goods Vehicle (LGV);

• Medium Goods Vehicle (MGV);

• Heavy Goods Vehicles (HGV).

The model time periods used for expansion are:

• AM period from 7:30am to 9:30am;

• Interpeak (IP) period from 11:00am to 3:00pm;

• PM period from 4:00pm to 6:00om.

Additional count surveys were undertaken in conjunction with RSIs, and have been used as controls for expansion. These counts were a Manual Classified Count (MCC) and an Automatic Traffic Count (ATC) at each site.

The MCC was used to expand the data to observed flows (by time period) on the day of survey and the ATC was used to correct this flow to the 3 week average.

11.7.3 Patching Missing Data Patching comprised using a proxy interview record in place of absent data. Proxy records were taken from interviews recorded during adjoining half hour time segments or, where necessary, a similar vehicle type.

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This was necessary for site 5 of the N13/N14/N15 study, which was surveyed in the afternoon only (between 2pm and 7pm). The trips from the inter-peak period (the middle of the day) were reused within the morning peak for the purpose of the matrix building.

Survey site 1 of the “Derry” 2006 study was suspended briefly between about 9am and 9:30am. To compensate, survey records from between 9:30am and 10am were used as part of the model time period.

11.7.4 Allocation of User Classes The user classes adopted within the A5 WTC traffic model are outlined in paragraph 11.4.

For car trips, the user class is determined by its origin and destination purposes, as set out in Table 11-1.

Table 11-1: User Classes of Car Trips used for A5 WTC Expansion Processes Destination Purpose Employers Other, e.g. Home Work Business Shopping Employers Home Invalid Commute Other Business Employers Employers Work Commute Other Business Business Employers Employers Employers Employers Employers Business Business Business Business Business Other, e.g. Employers Other Other Other Origin Purpose Shopping Business

11.7.5 Conversion of Alternate Zone Systems Trip records have zone numbers appended to facilitate the modelling process.

Origins and destinations were recorded in terms of street addresses which were then allocated to zones. Within Northern Ireland this used postcodes as an intermediate step. Addresses in Republic of Ireland do not have postcodes and were allocated to zones directly.

Trips ends recorded as part of earlier studies (not A5 WTC) did not always fit well into the A5 WTC zone system. Some adjustment was therefore required to “fit” this data to the A5 zone system.

The processes for matrix expansion are illustrated diagrammatically on Figure G-2 in Appendix G.

11.8 Matrix Building Initially, a set of “station” trip matrices was developed for each survey location and direction. These were amalgamated into complete matrices using the steps outlined below.

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11.8.1 Synthesis of Matrices for Reverse Direction The RSI surveys conducted for the A5 WTC study were carried in both traffic directions and reversal of these matrices was therefore not required.

The surveys obtained from previous studies were only carried out in one direction; generally inbound towards the area of study. These surveys therefore required a reversal process to be applied as part of the matrix building operation.

Reversed matrices were controlled to the relevant MCC and ATC. The reverse matrices were synthesised using the matrices developed for the forward direction with due regard to the appropriate trip purposes for the reverse direction.

11.9 Matrix Development 11.9.1 Synthesis of Unsurveyed Locations The A38 Lifford Bridge could not be surveyed for security reasons but the OD pattern was synthesised using observations on the N13, N14 and N15 roads in ROI.

11.9.2 Factoring Matrices to Common Base Year The Londonderry RSI survey and the N13/N14 N15 matrices were observed in 2006. The Cookstown RSI was from 2007. These were factored to the common base year of 2008.

Car trips were factored according to the trip end growth for each zone as derived from the TEMPRO-NI model. Growth factors for LGV and HGV were based on traffic flow trends.

11.9.3 Removal of Double Counting The individual “station” trip matrices have been aggregated to provide full datasets covering the study area but still split by time period and user class. Simple addition of the trip matrices would have resulted in double counting where movements could have been observed at more than one RSI cordon. Such trips were effectively divided by the number of cordons theoretically crossed (typically 2) to obtain a true average.

11.9.4 Gravity Model Infill After removal of double counting the study area trip matrices still omitted some unobserved parts, e.g. for movements wholly within or outside the survey cordons.

These were thus synthesised using Gravity Model procedures. Gravity models were calibrated based upon the observed trips and interzonal costs. The calibrated ‘formulae’ were then used to estimate the missing information.

11.10 Assignment Method The assignment procedure performs the 2 basic functions of:

• Building paths (or routes) between all pairs of origins and destinations

• Loading trips from the matrix onto the network, using the previously calculated paths.

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Link speeds are adjusted with speed/flow curves allocated to each link. A capacity restraint process operates (principally in urban areas), where assigned flows might otherwise exceed the nominal capacity of the links and junctions. The model uses an iterative procedure to achieve a balance between competing routes and stabilise link flows.

11.11 Model Validation 11.11.1 Validation Criteria The Design Manual for Roads and Bridges sets out acceptance guidelines for highway model validation criteria. The usual criteria for assessing the quality of the model validation are:

• Flow criteria using differences between observed and modelled flows

• Statistical criteria using the GEH statistic, which measures the goodness-of-fit between observed and modelled flows

• Comparison of observed and modelled journey times

11.11.2 Link Flow Calibration As a final step in model development, the model was ‘calibrated’ to link flows which used a matrix estimation process to adjust link flows iteratively to traffic counts. The success of this process was measured using a statistical comparison of the agreement between flows and counts.

11.11.3 Link Flow Validation Assigned model flows were compared with a set of validation traffic counts in order to assess the accuracy of the model and its ability to meet DRMB criteria. These counts were separate and independent of traffic data used for model calibration.

The DMRB states that traffic models should achieve 85% of links with flows within Criteria A and 85% of links should have GEH of less than 5.0. The DMRB criteria is shown in Table 11.2

The results of the model calibration are shown in Tables 11-3 and 11-4 for the flow comparison and Table 11-4 for the GEH comparison respectively. Both of these show results for all individual validation counts together. The Tables show that the model has achieved the required DMRB criteria for both flow and GEH in each time period.

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Table 11-2: Validation flow comparison summary

Observed count value Criteria A Criteria B Criteria C Observed flows less than 700 pcus Flows within Flows within Flows within 100 pcus 175 pcus 350 pcus Observed flows between 700 and 2700 pcus Flows within Flows within Flows within 15% 25% 50% Observed flows greater than 2700 pcus Flows within Flows within Flows within 400 pcus 675 pcus 1350 pcus

Table 11-3: Validation flow comparison summary

Range AM Peak Interpeak PM Peak Percentage pass for Criteria A 90% 90% 87% Percentage pass for Criteria B 100% 97% 99% Percentage pass for Criteria C 100% 100% 100%

Table 11-4: Validation GEH comparison summary

Range AM Peak Interpeak PM Peak Percentage of GEH between 0.0 and 5.0 89% 86% 85% Percentage of GEH between 0.0 and 7.0 95% 94% 96% Percentage of GEH between 0.0 and 10.0 99% 98% 100%

The link flow validations were also undertaken over a series of screenlines and cordons throughout the study area. The locations of these screenlines are shown in Figure 11.3.

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Figure 11-3 Validation Screenlines The DMRB validation criteria for screenlines flows is that the screenline totals need to be within ±/-5% and a GEH value of less than 4, for all (or nearly all) screenlines.

The results for each screenline location are shown in Table G-1 to G-3 in Appendix G and for each cordon location are shown in Table G-4 to G-6 in Appendix G. These tables show, for each screenline, the absolute and percentage difference between the observed and modelled flow, and the GEH statistic. It can be seen that these are

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11.11.4 Journey Time Validation Journey time surveys were undertaken in 2008 using ANPR. The ANPR data sets have been analysed to form the routes shown in Figure 11-3.

Figure 11-4: Journey Time Routes Used for A5WTC Traffic Model Validation

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The surveys were undertaken over 2 days for 12 hours (7am-7pm) each day and were conducted using ANPR cameras at 64 locations along the A5 corridor. These were conducted in accordance with the advice given in DMRB to ensure adequate sampling.

The validation is based on comparisons of observed and modelled journey times along these routes, including intermediate timing points at major intersections. The validation criteria is based on modelled times being within 15% of observed times for 85% of routes. However, on congested networks it is more appropriate to compare modelled times to the range of observed maximum and minimum times to give a fuller indication of the variation along a route.

Table 11-5 shows the journey time summary statistics for the morning peak hour, interpeak, and evening peak hour respectively.

Table 11-5: Morning Peak (AM) Journey Time Analysis

% of routes Journey Time Validation within 15% or 1 min

AM 90% IP 90% PM 95%

11.11.5 Summary of Model Validation In summary, the model validation process has demonstrated that the base year traffic models provide a satisfactory depiction of current traffic demands and conditions in the A5 WTC Study area and therefore provide a reliable basis from which to prepare traffic forecasts for future growth and scheme development.

11.12 Base Year Flows Base year traffic flows are presented in Figures 11.8-11.10 these figures show that the urban areas of Strabane and Omagh carry significant levels of traffic when compared to rural sections.

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A5 WTC Base Year 2008 Section 1 AM, IP, PM and AADT Flow

LONDONDERRY

BASE YEAR AM 1006 A40 IP 796 PM 1024 A6 AADT 11154

NEW BUILDINGS

N BREADY B48

BASE YEAR AM 1100 BASE YEAR IP 1272 AM 1039 PM 1540 IP 774 AADT 17080 PM 1064 AADT 11110

N14 B49 R264

BALLYMAGORRY

LIFFORD BASE YEAR AM 1204 IP 1139 PM 1473 AADT 15934 N15 STRABANE

B72 BASE YEAR AM 980 IP 803 PM 1041 AADT 11283 LEGEND: Existing A5 Border

Figure 11-5: Section 1 Base year (2008) Traffic Flows

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A5 WTC Base Year 2008 Section 2 AM, IP, PM and AADT Flow

N14 STRABANE

N15 BASE YEAR AM 1048 IP 849 PM 1132 AADT 12042 N B72

B164

B47

NEWTOWNSTEWART BASE YEAR AM 1086 IP 802 PM 1146 BASE YEAR AADT 11495 AM 1063 IP 792 PM 1185 AADT 11498

BASE YEAR AM 1424 IP 1301 B48 PM 1649 AADT 18157 B50 OMAGH

A505

BASE YEAR A32 AM 1534 IP 1176 PM 1580 AADT 16673

LEGEND: B122 B83 Existing A5 Border

Figure 11-6: Section 2 Base Year (2008) Modelled Traffic Flows

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A5 WTC Base Year 2008 Section 3 AM, IP, PM and AADT Flow

OMAGH

BASE YEAR A505 AM 943 N A32 IP 750 PM 979 AADT 10262

BASE YEAR AM 878 IP 737 B46 B122 PM 966 B83 AADT 9887

B46

BALLYGAWLEY

A4 B35

A28 AUGHER BASE YEAR B128 AM 538 IP 504 PM 606 AUGHNACLOY A28 AADT 6508

BASE YEAR AM 543 IP 559 PM 700 AADT 7627

LEGEND: Existing A5 Border

Figure 11-7 Section 3 Base Year (2008) Modelled Traffic Flows

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11.13 Forecasting SM 11.13.1 Introduction As is customary with roads projects it has been necessary to prepare future forecasts of traffic growth to support the assessment of Scheme options and the economic and environmental appraisals for the project.

In the case of the A5 WTC project, there has also been a need to develop a specific growth factoring tool.

This is described in the following sections.

11.13.2 Derivation of Growth Forecasts In order to predict traffic growth, it has been necessary to provide an estimation of potential growth in housing, population and employment from the present time (model base date) to the forecast years. These factors have been used to define future car ownership and usage and hence the potential growth in traffic between model zones.

In Great Britain (GB) this process uses the TEMPRO model which has been developed by the Department for Transport as a computer tool for predicting the growth in travel demand. To date, this has excluded Northern Ireland and a previous model called NISTRM was developed for Roads Service. However, the NISTRM model is currently dated and its demographic assumptions have been superseded. As a result (and in agreement with Roads Service) it was decided to create a bespoke version of TEMPRO for Northern Ireland in order to provide the traffic growth forecasts for the A5 WTC project and provide a forecasting tool that Roads Service can use on other projects. This tool is referred to as TEMPRO NI.

TEMPRO NI essentially comprises 3 sub-models:-

• Scenario Generator – for demographic data inputs and manipulation

• NATCOP – for car ownership forecasts

• CTRIPEND – for trip end forecasts

The model was setup using the following basic definitions:

• Base Year: 2001

• Forecast Years: 2006; 2011; 2016; 2021; 2026; 2031

• Zone System: 1 Zone = 1 Ward

• Time Periods: Weekday AM Peak, PM Peak, IP and Off Peak; Saturday; Sunday

• Balancing Area: one balancing area covering Northern Ireland.

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- actual car ownership - demographic data - area type definition (for base and forecast years) - household income - household expenditure (for base year)

Scenario Generator NATCOP - journey to work data - area type definition - parameters for production, attraction, mode split and time split

CTRIPEND

Trip End Forecasts by Zone: - Production-Attraction - Origin-Destination (by Mode, Purpose and Time Period)

Figure 11-8: Diagram of Model Structure

11.13.3 Data Sources, Households and Jobs The methodology used for developing TEMPRO NI was similar to that used for the GB version of TEMPRO; Northern Ireland is treated as an additional TEMPRO region. Below is a summary of the main Northern Ireland specific data sources and inputs used in the derivation of growth forecasts:

• 2001 Census: ward level data on population by age and work status, households by household size, workers by gender and working status, area types based on population density and settlement size, car ownership, journey to work data giving commuting by mode and ward of residence and work, together with commuter density at the workplace.

• Northern Ireland Statistics and Research Agency (NISRA) forecasts: district level forecasts of households and population by gender and age group.

• Experian Ltd: Experian were commissioned to provide Northern Ireland level forecasts of jobs by sector, gender and full or part time.

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• Oxford Economics: The Oxford Economics report “Business Land Need Study” was used to split Northern Ireland level jobs data down into district level.

• CACI Ltd: Base year data on average household income at ward level.

Tables setting out the forecasts of households and jobs which were input into the TEMPRO NI model are included in Tables G-7 and G-8 in Appendix G.

11.13.4 TEMPRO NI Forecasts As set out in the previous section, TEMPRO NI uses a number of base year inputs and 4 of the major quantities are households, workers, jobs and car ownership. Forecasts of households and jobs are also input and, using these, TEMPRO produces forecasts of the number of workers and levels of car ownership. Graphs showing the predicted growth of these variables are contained in Figures G.3 to G-6 in Appendix G.

For comparison purposes, the predicted growth in these factors is shown alongside the equivalent TEMPRO data for GB (England, Scotland and Wales combined) and Wales separately. Wales has been selected as a specific region as it is considered to have generally similar attributes to Northern Ireland, in terms of size, population and geography.

Of the 3 regions, Northern Ireland shows the highest growth of all 4 quantities: households, workers, jobs and car ownership. For workers and jobs, in particular, the growth rate is highest between 2001 and 2006, after which the growth rate returns to levels more similar to the other 2 regions.

11.13.5 TEMPRO NI Traffic Forecasts Using this basic input data, together with many other data sets, TEMPRO NI can predict the annual average (car driver) trip-end growth as shown in Table G-9 and Figure G-10 contained in Appendix G. Over the entire period until 2031, forecast trip end growth for Northern Ireland is slightly higher than that for GB and also higher than Wales.

11.13.6 Estimated Growth from A5 WTC Cube Model Traffic growth forecasts from TEMPRO NI were applied to the A5 WTC Cube Model at zone level. Forecasts of the growth in car driver origins and destinations were applied by time period: AM, IP and PM, and by purpose: Commute, Business & Others.

The Zone system for the A5 Cube model is different but compatible with TEMPRO NI. Where A5 Zones are smaller than TEMPRO NI wards, the growth factor for the ward has been uniformly applied to all of the A5 Zones within the ward. Where A5 Zones are larger than wards, the trip ends are aggregated to the larger A5 Zone size and growth factors are calculated from these aggregated values.

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The A5 Cube model has 337 Zones defined within Northern Ireland, against the 582 Wards used as Zones in TEMPRO NI.

Forecasts for LGV and HGV were derived in accordance with DfT WebTAG guidance (TAG unit 3.15.1). This TAG unit applies to forecasts for England and to adjust them to Northern Ireland conditions the following adjustment factor has been used:

TEMPRO NI car driver trip - ends growth

TEMPRO GB car driver trip - ends growth

Table G-11 in Appendix G presents matrix totals from the A5 WTC model. It shows the total number of trips (PCU) broken down by purpose, mode, time period and year.

Table G-12 in Appendix G shows the growth in trips in terms of percentage increases between the model base year, 2008, and the future years 2014 and 2029. This is shown for the 3 time periods, AM, IP and PM. It presents the growth both as a total increase from the base year, and then as an annual compound growth rate. The table shows that trip growth is higher in the early period between 2008 and 2014 at about 2.5% per annum, than over the period 2008 to 2029 when it is lower at about 1.6% per annum. This reflects the forecasts produced by TEMPRO NI and TEMPRO for GB where these models predict traffic growth to tail off over the coming decades. The table also shows the growth in inter peak trips is slightly higher than AM and PM trip growth.

11.13.7 Do-Minimum Network The future year traffic model has taken account of the effects of other road and traffic management schemes. The schemes scheduled to be completed by the A5 WTC scheme opening year 2014 and design year 2029 were:

• A4 Dungannon to Ballygawley Dual carriageway improvements – including the associated improvements on the A5 Tullyvar section.

• A2 Northwest Londonderry improvements to strategic route between Londonderry and the ROI border.

These schemes have been included within the road modelling to define the “Do Minimum” future highway network.

11.13.8 Do-Something Networks A series of Do Something networks have been derived, to describe each of the alternative scheme options. These have been described in further detail in Chapter 3.

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11.14 Forecasting Results

11.14.1 Do-Minimum Forecast The forecasts indicate an overall increase in traffic demand (trips) of over 16% between 2008 and 2014 and 40% by 2029. As a result, traffic in A5WTC study area is likely to experience deterioration in travel conditions during peak travel times, for example:

• average end to end journey times would increase across the study area by approximately 10%, from 74 minutes in the Base Year (2009) to 81 minutes in 2029. These forecasts show that continued traffic growth, in the absence of the A5WTC, will have a severe impact on the existing A5. Strabane, Omagh and urban roads in other areas will also come under increased pressure. Higher flows in the future are likely to cause severe congestion which significantly reduces traffic speeds and increases journey times.

11.14.2 Do Something Forecasts The various proposed routes for the A5WTC scheme have been tested as potential Do-Something schemes. The forecasts produced for each of these routes show that travel conditions in A5WTC can be improved through the introduction of a suitable route.

Across the study area the forecasts show that each of the finally selected routes would:

• reduce traffic flows in the urban areas by at least 30% in 2014 and by 40% in 2029 • decrease the average end to end journey times in 2029 by 33%, from 81 minutes in the Do Nothing to 54 minutes in the Do Something, and • decrease the same journey times from 74 minutes in the Base Year (2009) to 54 minutes in 2029, a reduction of some 27%.

Traffic conditions are therefore likely to improve significantly with any of the routes in place compared to the existing situation.

The main benefits are transfer of strategic traffic from the current A5 to the new road, through the urban areas and the improvement in traffic speeds and journey times offered by each route along the existing A5. With any of these routes in place, journey times not only improve relative to the Do-Minimum, but forecasts indicate that journey times will also be reduced significantly when compared to the base year (2008).

11.14.3 Route Selection During the Route development and selection process, described in Chapter 3 of this report, the Highway Design Team generated a series of Routes for each of the 3 sections. These were then appraised by the various team disciplines to determine the key features of each Route, their impacts and the nature of any constraints.

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The appraisal by the non-traffic disciplines was based on geographical locations which allowed consideration on a section by section basis. However, tests of the traffic and economic models indicated that it was not possible to assess options for discrete sections only. The results for Routes on a single section were sensitive to the changes in traffic flows and conditions on neighbouring sections and other parts of the network. As a result it was necessary to assess complete end to end Route from New Buildings to Aughnacloy.

The 4 alternative Routes for each of the 3 sections gave a theoretical total of 64 possible combinations for the total end to end Route. However, not all these combinations were deemed feasible, and it was established that only 32 of the combinations were viable. The Route alignments between Sections 2 & 3 do not all meet at common locations and do not allow for all alignments between sections to be combined.

Accordingly, the traffic model was run for each of the 32 Route combinations and the outputs processed through TUBA to generate link transit benefits in terms of Present Value Benefits (PVB) (which comprise Consumer User Benefits and Business Benefits but excludes Accident and Wider Economic Benefits).

The process of estimating the economic benefits of the Routes is presented, in section 11.16.

Table 11-6: Viable Route Tests

Colour coding PVB

Section 1 Section 2 Section 3 (£Million)

Purple Black Pink 851.0 Purple Black Red 816.7 Purple Purple Pink 825.7 Purple Purple Red 749.0 Purple Red Pink 820.5 Purple Red Red 770.7 Purple Yellow Green 856.8 Purple Yellow Purple 857.7 Brown Black Pink 860.9 Brown Black Red 814.7 Brown Purple Pink 822.8 Brown Purple Red 780.7 Brown Red Pink 830.8 Brown Red Red 781.4 Brown Yellow Green 855.7 Brown Yellow Purple 860.8 Green Black Pink 865.3

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Green Black Red 819.5 Green Purple Pink 833.7 Green Purple Red 789.7 Green Red Pink 830.9 Green Red Red 778.5 Green Yellow Green 859.6 Green Yellow Purple 865.8 Pink Black Pink 845.4 Pink Black Red 806.3 Pink Purple Pink 799.8 Pink Purple Red 765.3 Pink Red Pink 819.4 Pink Red Red 766.4 Pink Yellow Green 847.0 Pink Yellow Purple 848.9

The results in Table 11-6 are presented as a hierarchy of Routes for Sections 1 and 2 respectively. Options for Section 1 are presented in the order of Purple, Brown, Green and Pink. Within each of these the results are then presented for Black, Purple, Red and Yellow in Section 2 and finally the results are completed using viable options in Section 3.

It can be seen that the PVB Benefits range from £749 Million for the combination of Purple/Purple/Red to £866 million for Green/Yellow/ Purple. The PVB values are expressed in terms of 2002 prices discounted to 2002, in accordance with conventional practice.

At this time, the original Brown Route in Section 1 was identified as having very high construction costs, environmental issues and economic considerations and a new route was developed (called Black), which was a variant of the Pink Route. Further details on this high-level elimination of routes can be read in paragraph 11.15.

11.14.4 Predicted Traffic Relief on Existing Road Network Each of the Routes provides relief to the existing road network. In order to demonstrate the extent of relief achieved, Table 11.2 shows the percentage reduction on the existing A5 road for various Routes. In addition to this, there is also some relief to other parallel roads which is not shown in the table.

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Table 11-7: Route Relief Comments by Section

Route Comments Black No Relief North of Strabane – Online Improvement Relief Around Strabane – 80% Predicted high traffic flow through urban area of Strabane Pink Relief North of Strabane – 80%

Section 1 No relief through Strabane – Online Improvement Test Predicted high traffic flow through urban area of Strabane Purple Relief North of Strabane – 80% Relief Around Strabane – 25-30% Green Relief North of Strabane – 80% Relief Around Strabane – 25-30% Purple Relief North of Omagh – 85% Relief Around Omagh – 30% Yellow Relief North of Omagh – 85%

Section 2 Relief Around Omagh – 30% Test Red Relief North of Omagh – 85% Relief Around Omagh – 30% Black Relief North of Omagh – 85% Relief Around Omagh – 30% Red Relief North of A4 – 65% Relief South of A4 – 50% Ideal Junction location South of Omagh Pink Relief North of A4 – 85% Relief South of A4 – 50%

Section 3 Ideal Junction location South of Omagh Test Purple Relief North of A4 – 65% Relief South of A4 – 40% Poor Junction location South of Omagh Green Relief North of A4 – 50% Relief South of A4 – 80% Poor Junction location South of Omagh

In order to demonstrate the extent of relief to the A5 on a section by section basis, it has been necessary to vary the routes on the section in question, but hold those on the other sections constant. For example, each of the routes for Section 1 were tested with Sections 2 and 3 coded with the Black and Pink Routes respectively.

Similarly, the routes for Section 2 were tested with the Pink Route for Section 1 and the Pink Route for Section 3. In the case of Section 3 routes, the Pink and Black Routes were held constant for Section 1 and 2 respectively.

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11.14.5 Forecast Traffic Flows Traffic flows for key links in each section were extracted. The traffic flows for Section 1 Route tests are shown in Figures 11.9 to 11.12.

In these figures it can been seen that the traffic forecasts north of Strabane are very similar for all routes and the only variation between the options results from the way in which the proposed highway integrates with the local highway network. This is more apparent in the Pink and Black options which offer little relief to the Strabane urban area, and are predicted to have traffic flows of 27,000 vehicles per day. The Green and Purple Route do offer some transfer between the local roads and the A5 WTC scheme, but Strabane is a strong generator and attractor of trips and any route will not offer 100% transfer to an alternative route.

The traffic flows for the Section 2 tests are shown in Figures 11.13 to 11.16. Each route offers a similar amount of transfer. The only difference that can be seen in the traffic flows is around Newtownstewart. The Purple and Red Routes transfer a higher proportion of traffic away from the existing A5 when compared to the Black and Yellow Routes.

The Traffic flows for the Section 3 tests are shown in Figures 11.17 to 11.20. The Pink Route in Section 3 provides the highest proportion of traffic transfer from the existing A5 of all routes between Omagh and the A4. The Green Route provides the greatest transfer of traffic between the A4 and the ROI border.

The traffic transfer between Omagh and the A4 is controlled by 2 factors:-

• The choice of whether the Route should be east or west of Garvaghy Big Hill; and

• The proximity of the new junction to the south Omagh in relation to the town.

The difference between east and west of Garvaghy Big Hill can been seen when the Red and Pink Routes are compared. The Red Route only provides a transfer of 65% when compared to the 85% of the Pink Route.

It is recognised that these figures (the 65% and 85% traffic transfer figures) are based on an assumption that traffic travelling from the A4 east have an easy option of travelling north via the existing road network and that subsequent junction strategy and design can influence these figures.

The second comparison can be seen when comparing the Purple and Pink Routes. Both Routes are similar in alignment south of the B46 but the junction location for the Purple Route is further from Omagh, which results in a reduction in traffic transfer.

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Comparison of Do Something with Do Minimum AM, IP, PM and AADT Flows for A5 WTC Black Route in Section 1 in Years 2014 and 2029

2014 2029 DM DS Diff. 00 LONDONDERRY 1138 1417 279 0 0 917 1065 148 0 0 1140 1407 267 00 12800 15120 2320 A40 1351 1755 404 1073 1317 244 1312 1704 392 A6 15001 18671 3670

NEW BUILDINGS DM DS Diff. 1171 216 -955 892 156 -736 1184 288 -896 12732 2517 -10215 1390 255 -1135 1043 186 -857 1373 345 -1028 N BREADY B48 14932 3001 -11931

DM DS Diff. 2014 2029 1273 1035 -238 1235 1538 1465 1225 -240 884 1101 1794 1357 -437 1163 1420 19714 16253 -3461 12545 15611 1622 1249 -373 1819 1505 -314 2224 1693 -531 24520 19950 -4570

N14 2014 2029 1823 2253 R264 B49 1564 1954 2081 2539 BALLYMAGORRY 21967 27348 LIFFORD

DM DS Diff. 1391 1823 432 1334 1564 230 1747 2081 334 N15 18565 21967 3402 STRABANE 2014 2029 1703 2253 550 1423 1784 1614 1954 340 1343 1653 2111 2539 428 1812 2205 22534 27348 4814 DM DS Diff. B72 19010 23450 1097 1423 326 LEGEND: 948 1343 395 Existing A5 1183 1812 629 2014 2029 Black Route 13029 19010 5981 430 589 Border 1304 1784 480 438 562 AM Existing Existing 1129 1653 524 644 809 IP Black A5 A5 1340 2205 865 5984 7749 PM Route 2014 2029 15404 23450 8046 AADT

Figure 11-9: Traffic Flows for Section 1 - Black Route

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Comparison of Do Something with Do Minimum AM, IP, PM and AADT Flows for A5 WTC Pink Route in Section 1 in Years 2014 and 2029

2014 2029 DM DS Diff. 00 LONDONDERRY 1138 1421 283 0 0 917 1066 149 0 0 1140 1410 270 00 12800 15137 2337 A40 1351 1768 417 1073 1303 230 1312 1702 390 A6 15001 18572 3571

NEW BUILDINGS DM DS Diff. 1171 216 -955 892 156 -736 1184 288 -896 12732 2517 -10215 1390 255 -1135 1043 186 -857 1373 345 -1028 N BREADY B48 14932 3000 -11932

DM DS Diff. 2014 2029 1273 971 -302 1239 1552 1465 1136 -329 885 1088 1794 1311 -483 1166 1417 19714 15125 -4589 12562 15512 1622 1202 -420 1819 1410 -409 2224 1630 -594 24520 18752 -5768

N14 2014 2029 B49 1811 2259 R264 1575 1944 2042 2489 BALLYMAGORRY 21972 27168 LIFFORD

DM DS Diff. 1391 1811 420 1334 1575 241 1747 2042 295 N15 18565 21972 3407 STRABANE 2014 2029 1703 2259 556 1411 1798 1614 1944 330 1083 1350 2111 2489 378 1463 1806 22534 27168 4634 DM DS Diff. B72 15774 19762 1097 1411 314 LEGEND: 948 1083 135 Existing A5 1183 1463 280 2014 2029 Pink Route 13029 15774 2745 436 583 Border 1304 1798 494 489 657 AM Existing Existing 1129 1350 221 642 830 IP Pink A5 A5 1340 1806 466 6516 8741 PM Route 2014 2029 15404 19762 4358 AADT

Figure 11-10: Traffic Flows for Section 1 – Pink Route

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Comparison of Do Something with Do Minimum AM, IP, PM and AADT Flows for A5 WTC Purple Route in Section 1 in Years 2014 and 2029

2014 2029 DM DS Diff. 1241 1618 LONDONDERRY 1138 124 -1014 972 1239 917 54 -863 1295 1570 1140 99 -1041 13901 17433 12800 889 -11911 A40 1351 129 -1222 1073 53 -1020 1312 100 -1212 A6 15001 925 -14076

NEW BUILDINGS DM DS Diff. 1171 215 -956 892 153 -739 1184 283 -901 12732 2475 -10257 1390 255 -1135 1043 182 -861 1373 341 -1032 N BREADY B48 14932 2953 -11979

DM DS Diff. 2014 2029 1273 966 -307 1183 1527 1465 1171 -294 847 1077 1794 1354 -440 1155 1384 19714 15739 -3975 12240 15310 1622 1206 -416 1819 1478 -341 2224 1693 -531 24520 19602 -4918

N14 2014 2029 B49 800 1018 R264 619 765 817 1015 BALLYMAGORRY 8707 10828 LIFFORD

DM DS Diff. 1391 880 -511 1334 878 -456 1747 1186 -561 N15 18565 12337 -6228 STRABANE 2014 2029 1703 1097 -606 800 1018 1614 1100 -514 619 765 2111 1463 -648 817 1015 22534 15253 -7281 DM DS Diff. B72 8707 10828 1097 372 -725 LEGEND: 948 273 -675 Existing A5 1183 364 -819 2014 2029 Purple Route 13029 4132 -8897 671 823 Border 1304 478 -826 538 664 AM Existing Existing 1129 378 -751 769 958 IP Purple A5 A5 1340 438 -902 7600 9439 PM Route 2014 2029 15404 5576 -9828 AADT

Figure 11-11: Traffic Flows for Section 1 – Purple Route

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Comparison of Do Something with Do Minimum AM, IP, PM and AADT Flows for A5 WTC Green Route in Section 1 in Years 2014 and 2029

2014 2029 DM DS Diff. 1136 1367 LONDONDERRY 1138 291 -847 950 1142 917 121 -796 1157 1349 1140 263 -877 13283 15752 12800 2114 -10686 1351 391 -960 A40 1073 172 -901 1312 342 -970 A6 15001 2922 -12079

NEW BUILDINGS DM DS Diff. 1171 193 -978 892 114 -778 1184 215 -969 12732 1894 -10838 1390 223 -1167 1043 131 -912 1373 258 -1115 N BREADY B48 14932 2223 -12709

DM DS Diff. 2014 2029 1273 976 -297 1267 1569 1465 1178 -287 930 1151 1794 1371 -423 1249 1489 19714 15855 -3859 13427 16352 1622 1220 -402 1819 1497 -322 2224 1709 -515 24520 19894 -4626

N14 2014 2029 B49 871 1065 R264 686 815 877 1092 BALLYMAGORRY 9568 11513 LIFFORD

DM DS Diff. 1391 868 -523 1334 861 -473 1747 1179 -568 N15 18565 12179 -6386 STRABANE 2014 2029 1703 1060 -643 871 1065 1614 1085 -529 686 815 2111 1446 -665 877 1092 22534 15063 -7471 DM DS Diff. B72 9568 11513 1097 338 -759 LEGEND: 948 216 -732 Existing A5 1183 274 -909 2014 2029 Green Route 13029 3362 -9667 358 468 Border 1304 426 -878 322 447 AM Existing Existing 1129 283 -846 473 595 IP Green A5 A5 1340 352 -988 4307 5887 PM Route 2014 2029 15404 4371 -11033 AADT

Figure 11-12: Traffic flows for Section 1 – Green Route

Comparison of Do Something with Do Minimum AM, IP, PM and AADT Flows for A5 WTC Black Route in Section 2 in Years 2014 and 2029

N14 DM DS Diff. STRABANE 1199 211 -988 999 170 -829 1287 213 -1074 13932 2464 -11468 N15 1424 225 -1199 1180 203 -977 1481 220 -1261 16395 2834 -13561

2014 2029 N B72 1465 1816 1109 1379 2014 2029 1573 1977 1226 1535 15814 19736 934 1187 1331 1681 13236 16828

DM DS Diff. B164 2014 2029 1237 316 -921 1292 1578 922 185 -737 B47 953 1209 1307 329 -978 1393 1730 NEWTOWNSTEWART 13223 2861 -10362 13556 17041 1488 346 -1142 1109 215 -894 1537 362 -1175 15854 3242 -12612 DM DS Diff. 1199 252 -947 DM DS Diff. 918 190 -728 1662 1140 -522 1347 336 -1011 1568 1062 -506 13254 2993 -10261 1920 1296 -624 1415 308 -1107 2014 2029 21795 15341 -6454 1108 242 -866 903 1137 1965 1326 -639 1568 411 -1157 742 947 1967 1376 -591 15858 3758 -12100 1027 1343 2432 1699 -733 10079 12903 27290 19737 -7553 B48

B50 OMAGH

2014 2029 A505 892 1189 742 970 982 1358 10230 13542 A32

DM DS Diff. LEGEND: 1841 1215 -626 Existing A5 1391 907 -484 Black Route 1883 1205 -678 Border 19920 13385 -6535 B122 B83 AM 2231 1452 -779 Existing Existing IP Black 1735 1119 -616 A5 A5 PM Route 2303 1427 -876 2014 2029 AADT 24770 16402 -8368

Figure 11-13: Traffic flows for Section 2 – Black Route

Comparison of Do Something with Do Minimum AM, IP, PM and AADT Flows for A5 WTC Yellow Route in Section 2 in Years 2014 and 2029

N14 DM DS Diff. STRABANE 1199 216 -983 999 170 -829 1287 205 -1082 13932 2456 -11476 N15 1424 227 -1197 1180 204 -976 1481 213 -1268 16395 2830 -13565

2014 2029 N B72 1450 1817 1104 1364 2014 2029 1581 1981 1208 1532 15751 19627 928 1178 1331 1681 13146 16758

DM DS Diff. B164 2014 2029 1237 326 -911 1275 1585 922 185 -737 B47 964 1218 1307 326 -981 1418 1799 NEWTOWNSTEWART 13223 2875 -10348 13695 17301 1488 353 -1135 1109 215 -894 1537 361 -1176 15854 3247 -12607 DM DS Diff. 1199 336 -863 DM DS Diff. 918 301 -617 1662 1139 -523 1347 391 -956 1568 1088 -480 13254 4411 -8843 1920 1288 -632 1415 434 -981 2014 2029 21795 15545 -6250 1108 376 -732 871 1123 1965 1343 -622 1568 482 -1086 696 901 1967 1390 -577 15858 5536 -10322 1022 1312 2432 1664 -768 9588 12394 27290 19792 -7498 B48

B50 OMAGH

2014 2029 A505 838 1103 685 905 936 1260 9497 12604 A32 DM DS Diff. LEGEND: 1841 1284 -557 Existing A5 1391 959 -432 Yellow Route 1883 1322 -561 Border 19920 14230 -5690 B122 B83 AM 2231 1569 -662 Existing Existing IP Yellow 1735 1190 -545 A5 A5 PM Route 2303 1617 -686 2014 2029 AADT 24770 17659 -7111

Figure 11-14: Traffic flows for Section 2 – Yellow Route

Comparison of Do Something with Do Minimum AM, IP, PM and AADT Flows for A5 WTC Purple Route in Section 2 in Years 2014 and 2029

N14 DM DS Diff. STRABANE 1199 416 -783 999 328 -671 1287 412 -875 13932 4763 -9169 N15 1424 508 -916 1180 390 -790 1481 491 -990 16395 5712 -10683

2014 2029 N B72 1246 1507 948 1156 2014 2029 1365 1687 1374 1683 13443 16439 974 1200 1463 1835 14092 17425

DM DS Diff. B164 2014 2029 1237 151 -1086 1418 1736 922 123 -799 B47 1096 1341 1307 172 -1135 1604 1950 NEWTOWNSTEWART 13223 1757 -11466 15616 19108 1488 170 -1318 1109 141 -968 1537 178 -1359 15854 1957 -13897 DM DS Diff. 1199 111 -1088 DM DS Diff. 918 65 -853 1662 1143 -519 1347 132 -1215 1568 1100 -468 13254 1111 -12143 1920 1296 -624 1415 139 -1276 2014 2029 21795 15655 -6140 1108 87 -1021 883 1127 1965 1328 -637 1568 185 -1383 733 919 1967 1396 -571 15858 1491 -14367 1032 1346 2432 1644 -788 10055 12680 27290 19787 -7503 B48

B50 OMAGH

2014 2029 A505 826 1109 696 915 922 1306 9618 12821 A32

DM DS Diff. LEGEND: 1841 1272 -569 Existing A5 1391 936 -455 Purple Route 1883 1267 -616 Border 19920 13822 -6098 B122 B83 AM 2231 1521 -710 IP Existing Existing Purple 1735 1150 -585 PM A5 2014 A5 2029 Route 2303 1538 -765 AADT 24770 17022 -7748

Figure 11-15: Traffic flows for Section 2 – Purple Route

Comparison of Do Something with Do Minimum AM, IP, PM and AADT Flows for A5 WTC Red Route in Section 2 in Years 2014 and 2029

N14 DM DS Diff. STRABANE 1199 157 -1042 999 164 -835 1287 151 -1136 13932 2156 -11776 N15 1424 186 -1238 1180 201 -979 1481 171 -1310 16395 2616 -13779

2014 2029 N B72 1493 1826 1073 1342 2014 2029 1592 1970 1166 1483 15706 19440 841 1123 1283 1626 12455 16033

DM DS Diff. B164 2014 2029 1237 307 -930 1368 1720 922 192 -730 B47 1037 1329 1307 322 -985 1573 1936 NEWTOWNSTEWART 13223 2868 -10355 15144 18936 1488 351 -1137 1109 221 -888 1537 366 -1171 15854 3329 -12525 DM DS Diff. 1238 112 -1126 DM DS Diff. 1047 59 -988 1662 1141 -521 1394 132 -1262 1568 1089 -479 14765 1053 -13712 1920 1291 -629 1491 139 -1352 2014 2029 21795 15527 -6268 1272 81 -1191 837 1114 1965 1335 -630 1639 180 -1459 671 916 1967 1390 -577 17838 1427 -16411 1011 1330 2432 1645 -787 9583 12592 27290 19751 -7539 B48

B50 OMAGH

2014 2029 A505 824 1102 688 918 927 1304 9550 12836 A32

DM DS Diff. LEGEND: 1841 1271 -570 Existing A5 1391 936 -455 Red Route 1883 1260 -623 Border 19920 13795 -6125 B122 B83 AM 2231 1526 -705 Existing Existing IP Red 1735 1155 -580 A5 A5 PM Route 2303 1542 -761 2014 2029 AADT 24770 17083 -7687

Figure 11-16: Traffic flows for Section 2 – Red Route

Comparison of Do Something with Do Minimum AM, IP, PM and AADT Flows for A5 WTC Pink Route in Section 3 in Years 2014 and 2029

OMAGH DM DS Diff. 1152 324 -828 896 223 -673 A505 1180 280 -900 N A32 12432 2793 -9639 1497 321 -1176 DM DS Diff. 1136 214 -922 1049 284 -765 1523 254 -1269 859 231 -628 16007 2847 -13160 1140 257 -883 11668 2380 -9288 1321 274 -1047 1050 215 -835 B46 B122 1425 235 -1190 B83 14457 2286 -12171

2014 2029 426 560 B46 359 472 2014 2029 486 637 1105 1494 5089 6561 940 1268 1233 1705 13511 18019 A4

BALLYGAWLEY

2014 2029 904 1235 A4 B35 741 1012 1055 1441 A28 11036 14749 AUGHER B128

AUGHNACLOY DM DS Diff. A28 636 282 -354 600 273 -327 N2 729 324 -405 7824 3338 -4486 798 333 -465 725 313 -412 908 399 -509 DM DS Diff. 9612 4033 -5579 624 429 -195 653 408 -245 809 525 -284 8884 5724 -3160 776 542 -234 2014 2029 LEGEND: 800 511 -289 221 280 Existing A5 990 652 -338 255 324 Pink Route 10943 7227 -3716 312 407 Border 3361 4240 AM Existing Existing IP Pink A5 A5 PM Route 2014 2029 AADT

Figure 11-17: Traffic flows for Section 3 – Pink Route

Comparison of Do Something with Do Minimum AM, IP, PM and AADT Flows for A5 WTC Green Route in Section 3 in Years 2014 and 2029

OMAGH DM DS Diff. 1152 575 -577 896 383 -513 A505 1180 555 -625 N A32 12432 5842 -6590 1497 706 -791 DM DS Diff. 1136 469 -667 1049 451 -598 1523 681 -842 859 292 -567 16007 7207 -8800 1140 443 -697 11668 4302 -7366 1321 544 -777 1050 333 -717 B46 B122 1425 519 -906 B83 14457 5044 -9413

2014 2029 434 568 B46 430 555 2014 2029 528 708 823 1083 5588 7293 745 984 940 1247 10012 13276 A4

BALLYGAWLEY

2014 2029 738 965 A4 B35 675 896 865 1141 A28 9020 11964 AUGHER B128

DM DS Diff. AUGHNACLOY A28 636 275 -361 600 211 -389 N2 729 282 -447 7824 2909 -4915 798 328 -470 725 242 -483 908 325 -583 DM DS Diff. 9612 3371 -6241 624 392 -232 653 341 -312 809 464 -345 8884 5003 -3881 776 486 -290 2014 2029 LEGEND: 800 426 -374 267 343 Existing A5 990 570 -420 343 431 Green Route 10943 6224 -4719 399 518 Border 4338 5487 AM Existing Existing IP Green A5 A5 PM Route 2014 2029 AADT

Figure 11-18: Traffic flows for Section 3 – Green Route

Comparison of Do Something with Do Minimum AM, IP, PM and AADT Flows for A5 WTC Red Route in Section 3 in Years 2014 and 2029

OMAGH DM DS Diff. 1152 806 -346 896 614 -282 A505 1180 776 -404 N A32 12432 8048 -4384 1497 899 -598 DM DS Diff. 1136 741 -395 1049 560 -489 1523 925 -598 859 440 -419 16007 9642 -6365 1140 576 -564 11668 5323 -6345 1321 595 -726 1050 492 -558 B46 B122 1425 617 -808 B83 14457 5854 -8603

2014 2029 348 432 B46 279 369 2014 2029 412 534 606 891 4314 5528 479 677 708 988 7477 10505 A4

BALLYGAWLEY

2014 2029 626 904 A4 B35 508 717 726 1029 A28 7822 10934 AUGHER B128

AUGHNACLOY DM DS Diff. A28 636 359 -277 600 351 -249 N2 729 398 -331 7824 4091 -3733 798 459 -339 725 407 -318 908 496 -412 DM DS Diff. 9612 4992 -4620 624 491 -133 653 465 -188 809 587 -222 8884 6254 -2630 776 627 -149 2014 2029 LEGEND: 800 583 -217 158 190 Existing A5 990 727 -263 195 241 Red Route 10943 7908 -3035 245 319 Border 2792 3445 AM Existing Existing IP Red A5 A5 PM Route 2014 2029 AADT

Figure 11-19: Traffic flows for Section 3 – Red Route

Comparison of Do Something with Do Minimum AM, IP, PM and AADT Flows for A5 WTC Purple Route in Section 3 in Years 2014 and 2029

OMAGH DM DS Diff. 1152 661 -491 896 495 -401 A505 1180 638 -542 N A32 12432 7207 -5225 1497 787 -710 DM DS Diff. 1136 599 -537 1049 422 -627 1523 750 -773 859 305 -554 16007 8697 -7310 1140 417 -723 11668 3996 -7672 1321 456 -865 1050 333 -717 B46 B122 1425 453 -972 B83 14457 4389 -10068

2014 2029 418 543 B46 335 466 2014 2029 483 605 770 1029 4892 6456 671 887 847 1198 9074 12162 A4

BALLYGAWLEY

2014 2029 765 1049 A4 B35 664 898 868 1206 A28 9335 12631 AUGHER B128

AUGHNACLOY DM DS Diff. A28 636 290 -346 600 296 -304 N2 729 328 -401 7824 3527 -4297 798 350 -448 725 327 -398 908 428 -480 DM DS Diff. 9612 4174 -5438 624 441 -183 653 428 -225 809 523 -286 8884 5851 -3033 776 551 -225 2014 2029 LEGEND: 800 518 -282 211 271 Existing A5 990 665 -325 235 324 Purple Route 10943 7294 -3649 314 391 Border 3229 4202 AM Existing Existing IP Purple A5 A5 PM Route 2014 2029 AADT

Figure 11-20: Traffic flows for Section 3 – Purple Route

11.15 Economic Appraisal of Routes 11.15.1 Assessment Methodology A full cost benefit assessment was required to allow the comparison of the ‘value for money’ provided by each of the Routes considered. The chosen tool for this part of the project was the TUBA computer program developed for the Department of Transport. This program compares the costs of operation of the “Do-Minimum” and “Do-Something” scheme network forecasts to compute the value of the savings in vehicle travel time and distance. By comparing all construction and associated costs with the stream of traffic benefits over a 60 year assessment period, TUBA provides a Benefit Cost Ratio (BCR) which allows comparison of the value for money of each option.

TUBA does not calculate benefits that are due to changes in accident costs and these were ascertained using COBA. In addition, a separate analysis of wider economic benefits has been undertaken by ECOTEC and these have been added into the Economic Appraisal. The outcome of the Wider Economic Benefit indicates that the proposed A5WTC scheme does have an impact on the wider economy. The WEB benefits have been estimated to be in the region of £140 Million.

TUBA Analysis

TUBA undertakes a matrix based appraisal, using as inputs; trip, time, distance and cost matrices. Scheme costs are also used as inputs to the program. Using this information TUBA calculates benefits for each of the modelled periods. These are then expanded to full years using annualisation factors, and then further expanded to represent the whole 60 year appraisal period.

Appraisal Periods / Modelled Years

The A5 traffic model consists of 3 separate validated models, representing an average hour in the AM peak period (07:30-09:30), PM peak period (16:00-18:00) and Inter peak period (11:00-15:00) respectively, for an average weekday. The model was also run for 2 years, 2014 and 2029. The validation achieved the requirements set out in the DMRB criteria and the model is therefore considered to be sufficiently robust for carrying out the economic assessment.

A 60 year appraisal period was used commencing with the scheme opening year.

Annualisation factors:

The annualisation factors are used to convert benefits for each time period to annual benefits.

The following annualisation factors have been used:

• AM peak – 676

• PM peak – 716

• Inter peak – 1526

• Off peak/Weekend/Bank Holidays – 2262

These take into account the number of hours in each year that each time period occurs.

Off peak/Weekend/Bank Holidays factors applies to the modelled interpeak hour.

User Classes

A total of 7 user classes were used in the economic assessment. These were as follows:

1) Car – Work

2) Car – Commute

3) Car – Other purposes

4) LGV – Personal business

5) LGV – Freight

6) OGV1

7) OGV2

11.15.2 Scheme Costs Scheme costs are in Table 4.3 and paragraph 10.7 in terms of construction, land, preparation and supervision costs at Quarter 1:2008 prices, and include optimism bias.

These have been converted to represent Present Value of Cost items (PVC) which are also expressed at 2002 prices, discounted to 2002.

11.15.3 Forecast Accident Data Details of the traffic accidents which took place between January 2003 and March 2007 on the road network between Londonderry and Aughnacloy have been collected and analysed. Table 11-8 presents a breakdown of the observed accidents for each year according to their severity.

Table 11-8: Accident Data Breakdown

Casualties Number of Year Total Accidents Fatal Serious Slight Casualties 2003 520 19 133 793 945 2004 521 17 128 781 926 2005 480 16 141 717 874 2006 450 22 121 652 795 2007* 121 8 26 164 198 Total 2092 82 549 3107 3738 *up to March 2007

COBA has been used to predict the change in accident costs for the 60 year period between the Do-Nothing and Do-Something scenarios. It uses the predicted flows from the CUBE/VOYAGER traffic model for each link, together with accident rates calculated from observed accident records. For new road links in the proposed Routes, standard rates have been used.

11.15.4 Results of the Economic Appraisal The 32 Route combinations were assessed. The BCRs were calculated using TUBA link transit benefits, Accident Benefits and Wider Economic Benefits, all summed to provide a full PVB and then divided by the Present Value of Costs (PVC). The PVCs were derived from the data presented in Table 10.1 in Chapter 10.

During the development of the traffic model a number of key points were identified:-

i. In Section 1, whether a bypass of New Buildings was justified or not

ii. In Section 1, whether the route should pass to the south /east or north/west of Strabane town centre.

iii. Also in Section 1, whether the north/west routes should follow the alignment of the current A5 throughpass or take a route to the west of the town, closer to the River Finn.

iv. In Section 2, whether the route should pass to the east or west of Newtownstewart.

v. Also in Section 2, whether the route should pass close to Omagh or further to the west.

vi. At the ‘join’ between Sections 2 and 3, should the junction with the A5 lie close to Omagh or further south west.

vii. In Section 3, whether the route should pass east or west of Garvaghy Big Hill.

796036/0000/R/011 Version 0.1 454 ©Mouchel 2009 Preferred Options Report Scheme Assessment Report 2 viii. Also in Section 3, what form and location should the junction take between the A4.

ix. In Section 3 again, whether the route should approach the ROI border to the east or west of Aughnacloy.

The implications of the above were considered in the assessment. The key traffic and economics factors were as follows:-

i. In Section 1, a single carriageway bypass of New Buildings provides economic benefits to the project

ii. In Section 1, the Pink Route route through Strabane would attract very high traffic flows on the on-line section, whilst the Black and Green Routes achieved high levels of relief to the current A5 route. The Green Route does not provide as much relief to the town of Strabane as the Pink and Black Routes. All Section 1 routes had similar BCRs

iii. In Section 2, a western bypass to Newtownstewart had a higher PVB than an eastern (on-line) route.

iv. In Section 2 (and the interface with Section 3), routes and junctions close to Omagh achieve better relief and accordingly have better PVBs.

v. In Section 3 the choice between east or west of Garvaghy Big Hill is indicated that Pink offers better relief than Red although it is recgonised that this subject to junction strategy at Ballygawley.

vi. In Section 3, a western route around Aughnacloy was significantly shorter than an eastern route and hence achieved a higher BCR. However this was subsequently deemed to be non viable due to the environmental impact on the Thistle field system. It also would provide poor connectivity to the A28 and less relief to Aughnacloy.

This assessment of the Routes was was taken forward to be considered during the determination of the Emerging Preferred Route.

The economic appraisal of the 32 Route combinations is presented overleaf in Table 11-9.

Table 11-9 BCR Ratings for the Combination of Routes Wider Route Options Scheme Accident Economic Total Section 1 Section 2 Section 3 Cost PVB PVC Benefits Benefits Benefit BCR Pink Yellow Green 1047 880.3 756 125 151 1156 1.53 Black Yellow Green 1066 894.9 770 125 154 1174 1.52 Black Yellow Purple 1100 900.4 794 125 155 1180 1.49 Pink Yellow Purple 1081 885.8 780 125 152 1163 1.49 Black Black Pink 1101 887.5 795 125 152 1165 1.47 Pink Black Pink 1082 872.9 781 125 150 1148 1.47 Green Yellow Green 1104 862.4 797 125 148 1135 1.42 Black Purple Pink 1104 851.1 797 125 146 1122 1.41 Pink Purple Pink 1085 836.5 783 125 144 1105 1.41 Green Black Pink 1139 865.3 822 125 149 1139 1.39 Green Yellow Purple 1138 865.8 821 125 149 1139 1.39 Purple Yellow Green 1108 834.1 800 125 143 1102 1.38 Black Black Red 1121 846.0 810 125 145 1116 1.38 Pink Black Red 1102 831.4 796 125 143 1099 1.38 Pink Red Pink 1120 841.4 809 125 144 1111 1.37 Black Red Pink 1121 826.8 810 125 142 1094 1.35 Purple Yellow Purple 1142 839.6 824 125 144 1109 1.35 Green Purple Pink 1142 833.7 824 125 143 1102 1.34 Purple Black Pink 1143 826.7 825 125 142 1094 1.33 Black Purple Red 1124 809.6 812 125 139 1074 1.32 Pink Purple Red 1105 795.0 798 125 137 1057 1.32 Green Red Pink 1101 785.3 795 125 135 1045 1.31

Wider Route Options Scheme Accident Economic Total Section 1 Section 2 Section 3 Cost PVB PVC Benefits Benefits Benefit BCR Green Black Red 1158 830.9 836 125 143 1099 1.31 Pink Red Red 1159 819.5 837 125 141 1085 1.30 Black Red Red 1140 799.9 824 125 137 1062 1.29 Purple Purple Pink 1146 790.3 827 125 136 1051 1.27 Green Purple Red 1162 789.7 839 125 136 1050 1.25 Purple Red Pink 1162 780.6 839 125 134 1040 1.24 Purple Black Red 1163 785.2 840 125 135 1045 1.24 Green Red Red 1178 778.5 851 125 134 1037 1.22 Purple Purple Red 1166 748.8 842 125 129 1002 1.19 Purple Red Red 1182 739.1 854 125 127 991 1.16

Note: to enable a comparison of Routes the Accident Benefits have been assumed to be constant for all route combinations

It should be noted that the BCRs quoted in this report have been based on initial cost estimates. These are suitable for comparing schemes at this stage but may alter (and potential decrease) as a results of further detailed analysis. It is also expected as a results of the refined costs estimates that the BCR for the Preferred Route will increase.