19 Traffic and ECONOMIC ASSESSMENT

19.1 Traffic Studies

19.1.1 Existing Survey Data

Traffic counts are carried out on an annual basis along the study section of the N22 on behalf of the National Roads Authority. Data has been obtained from the five regular count stations located between Ballyvourney and Ballincollig, for the period 1987-2000. This is not a complete dataset as only one site near the new cemetery at Macroom, has produced data for each year between 1987 and 2000. Counts are usually carried out in September and adjusted for monthly variations to give an estimate of Annual Average Daily Traffic (AADT). A summary of the traffic data from these existing survey stations is given in the table below:

Table 19.1: Survey Data 1990 - 2000

Survey Station, N22	AADT			% HCVs	Annual Traffic Growth Rates (%)
	1990	1995	2000	2000	1990-2000	1995-2000
West of Ballyvourney	2,602*	3,160	4,658	10	7.6	8.1
West of New Cemetery, Macroom	4,171	5,188	7,450	10	6.0	7.5
Coolcour	5,342	7,555^+	9,560	10	6.0	6.1
Ovens Bridge	5,790	8,905	12,527	12	8.0	7.1
Poulavone, near Ballincollig	16,246	20,061	18,459	10	#	#

* 1992 figures - no data available for 1990

+ 1996 figures - no data available for 1995

# AADT too variable to provide growth rate

The observed data can be briefly summarised as follows:

· AADT flows in 2000 ranged between 4,700 vehicles per day at the western end of the study road to 18,500 vehicles per day at the eastern end.

· The percentage of heavy commercial vehicles (%HCV) in 2000 was between 10 and 12% of AADT along the study section. For the majority of the survey stations the %HCV did not change significantly from 1990 to 2000.

· The observed annual traffic growth rates over the period 1990 to 2000 were generally high (between 6% and 8%).

· The observed annual traffic growth rates over the most recent period, 1995 to 2000, were also generally high (between 6% and 8%). The National Roads Needs Study (NRNS) has adopted 1995 as the traffic growth base year. The NRA annual growth rates for the period 1995 - 2000 are 6% for all national primary roads. The NRNS contains slightly higher than national average growth rates for the N22 between Ballyvourney and Ballincollig.

· Traffic flows at Ballincollig are the highest of the five sites. The 1990 and 1995 AADT figures for this site represent a relatively high base. It should be noted that this location is in fact marginally outside the study area and much influenced by Ballincollig traffic.

· AADT’s and %HGV’s are broadly consistent with flows quoted in RT580 ‘National Roads and Traffic Flow 1999’ for the N22 although the reference locations/sections are not directly compatible.

A search of existing data sources found no existing traffic count data for the regional roads within the study area, and no origin/destination or travel time data.

19.1.2 Study Surveys

Traffic surveys were conducted for the study during May and June 2001. The results of these surveys are summarised in the following section and traffic survey locations are shown on Fig 19.1.

Classified turning movement surveys at:

· both N22/R619 junctions;

· N22/R582 junction.

· N22/R618 junction

· N22/R584 junction;

· N22/R590 junction; and

· N22/R585 junction.

Temporary automatic traffic counts (ATCs) at 17 locations, comprising the most significant roads, below Regional status, joining the N22 over the study section. These are listed below (traffic was counted by direction, northbound and southbound unless otherwise stated):

· Site 17: Local Road South of N22, SW of Ballymakeery (NE/b & SW/b)

· Site 16: Local Road North of N22, East of Ballymakeery (NE/b & SW/b)

· Site 15: Local Road South of Lynch’s Crossroads

· Site 14: Local Road North of Lynch’s Crossroads

· Site 13: Local Road South of River Sullane, West of Macroom

· Site 12: Local Road North of N22, Macroom

· Site 11: Local Road South of N22 (S of Macroom)

· Site 10: Local Road West of N22 (E/b & W/b)

· Site 9: Athsollis Bridge, South of N22

· Site 8: Local Road South of N22 (North of Kilmurry)

· Site 7: Local Road South Ryecourt Bridge, Farnanes

· Site 6: Local Road North of N22, Farran

· Site 5: Local Road South of N22, Farran

· Site 4: Local Road North of N22, West of Ovens

· Site 3: Local Road West of Ovens, South of N22

· Site 2: Local Road Southwest of Ovens Bridge

· Site 1: Local Road South of N22 (Near Ovens)

The Roadside Interview Surveys collected origin-destination information at seven locations within the study area, as below:

· N22 west of Ballyvourney;

· N22 near Coolcour;

· N22 east of Ovens;

· R582 north of N22;

· R590 south of N22;

· R585 south of N22; and

· R619 north of N22.

Journey times were surveyed along eight major routes within the study area. The routes were as follows:

· N22 between Ballyvourney and Ovens;

· R582 between study boundary and N22 study boundary.

· R618 between R619 junction and N22 junction;

· R584 between study boundary and N22 junction;

· R587 between study boundary and R584 junction;

· R590 between study boundary and N22 junction;

· R585 between study boundary and N22 junction; and

· R619 between R618 junction and N22 junction;

19.1.3 Survey Methodology and Duration

All turning movement surveys were undertaken as continuous 12 hour (0700 - 1900) full manual classified counts for each movement from/to each arm of all the junctions selected. The following vehicle classifications were used (taken from NRA DMRB HD24/96): -

· Car

· Light Goods Vehicles

· OGV1 (2 and 3 axle rigid)

· OGV2 (3 axle and more articulated, 4 axle rigid)

· Buses and coaches

· Other

The automatic traffic counts were undertaken for a minimum of one week to enable reasonable estimates to be made of the average weekday traffic flows. Counting equipment was checked regularly to ensure it was functioning correctly and that data collection was continuous.

The ATC data was collected for three main purposes:

· to factor the origin-destination trip data collected at roadside interview sites to average weekday flow levels;

· to calibrate traffic flows in the traffic model along screen-lines and cordon; and

· to validate traffic flows in the traffic model.

Roadside Interviews (RSI) were conducted at all locations in accordance with relevant Republic of Ireland requirements. The methodology set out in TA 11/81 was used as the basis for the RSI survey. The direction of interview at all sites was inbound into the study area. Survey duration was 12 hours (0700-1900) with a simultaneous classified traffic count. The surveys were carried out with the full co-operation and assistance of the Co. Cork Garda.

The following information was collected by the Roadside Interview surveys: -

· Vehicle Type (car, van, heavy goods vehicle (rigid), articulated vehicle)

· Trip Purpose (commuting, business, retail, personal business, holiday/tourist, other)

· Number of Occupants

· Origin and Destination (place name and county). If either origin or destination was in Macroom, an additional question on the name of the street/area was asked

· Type of parking used (for trips with destination in Macroom only)

Journey time surveys employed the floating car method. A minimum of four runs, both directions, were completed for each route in each of three time periods; morning peak (0700 - 0900), afternoon peak (1700 - 1900), and inter peak (1000 - 1600).

A long term ATC will be placed on the N22 in the immediate future to provide an indication of variations in flow over periods greater than one week. This will assist in the derivation of robust estimates of AADT and help to confirm the accuracy of the traffic work undertaken to date. This ATC will be maintained for at least the remaining duration of the study.

19.1.4 Road Safety

The latest complete accident data, covering the period 1996 to 2000, for the study section of the N22 between Ballyvourney and Ballincollig has been provided by Cork County Council. This is summarised below:

· A total of 127 injury accidents

· 8 were fatalities (6.3% of total)

· 37 were serious (29.1% of total)

· 82 were minor injury (64.5% of total)

· Personal Injury Accident Rate of 0.197 per million vehicle kilometres

The personal injury accident rate along the route varies significantly year by year, as shown in Table 19.2.

Table 19.2: N22 Personal Injury Accident Rate By Year

Year	Personal Injury Accident Rate (PIA Rate)
1996	0.302
1997	0.209
1998	0.174
1999	0.135
2000	0.192
1996 - 2000	0.197

It can be seen that the average Personal Injury Accident rate for the route over the period from 1996 to 2000 is similar to the National average of 0.20 to 0.21 per million vehicle kilometres. However, when the PIA rate is compared year by year it can be seen that the accident rate along the route varies significantly, with accident rates of 0.302 in 1996 and 0.135 in 1999. The N22 reported severity split of 6.3%/29.1% is higher than the national average of 5.4%/28.9% for fatal/serious accidents respectively. In conclusion, the accident data indicates that the existing section of road has an accident rate comparable to the national average for a National Primary road, while the severity of accidents along the route is slightly worse than the national average for a National Primary Road.

Access to the new N22 Ballyvourney to Ballincollig road will be limited with infrequent junctions and no minor accesses. This will significantly reduce potential traffic conflict areas. It is therefore to be expected that the improved road will constitute a safer travelling environment than the existing road. The NRA default rates for the relevant types of new road are as follows:

Table 19.3: Default PIA Rates

Road standard	Personal injury accident rate (PIAs per million vehicle kms)
Dual 2-lane carriageway	0.12
Wide single 2-lane carriageway	0.18
Single 2-lane carriageway	0.17

These accident rates are all lower than the observed accident rate of 0.197 PIAs per million vehicle kilometres on the existing N22. This indicates the potential for accident savings following scheme opening, irrespective of the carriageway standard adopted.

19.2 Traffic Model

In order to carry out the traffic and economic assessment of the N22 Ballyvourney - Macroom - Ballincollig improvement it is necessary to develop a calibrated traffic model of the existing road network for the study area. The model can then be utilised to undertake comparative assessments of the route improvement options.

The traffic model has been developed using the modelling software SATURN and consists of specific AM peak hour, PM peak hour and Inter-peak hour models. The traffic model required the following data: -

· Traffic counts

· Origin – destination data

· Trip purpose

· Vehicle type

· Journey times and speeds

· Network carriageway standards

· Link lengths

· Junction configuration and control

· Speed limits

The programme of traffic surveys provided the requirements for the first five of these items. A network inventory of link lengths based on OSI maps, NRA and county council databases and route inventory surveys was compiled for the study area. This, in turn, provided the last four items of data in the above list.

19.3 Initial Traffic Data Analysis

The draft traffic survey report and survey data was completed in July 2001. The table below provides a brief summary of the existing traffic flows in the study area as revealed by the programme of classified counts undertaken for the study.

Table 19.4: Summary Of Traffic Flows 2001

Road No.	Location	Survey Date	12 hour flow (two-way vehs)	% HGV
N22	Site 27: West of Ballyvourney	24/5/01	5,042	9.1
N22	Site 26: East of Macroom	23/5/01	7,150	10.4
N22	Site 22: West of R582	29/5/01	6,599	8.4
N22	Site 23: West of R618	29/5/01	9,109	9.4
N22	Site 21: West of R584	23/5/01	8,056	8.9
N22	Site 20: West of R590	22/5/01	7,196	10.1
N22	Site 24: West of R585	22/5/01	6,453	10.7
N22	Site 19: West of R619 (West)	22/5/01	7,298	9.8
N22	Site 18: East of R619 (East)	22/5/01	7,121	9.1
N22	Site 25: West of Ballincollig	23/5/01	8,612	10.4
R582	Site 31: North of Macroom	24/5/01	2,635	9.7
R590	Site 30: North of Crookstown	6/6/01	1,908	9.7
R585	Site 29: North of Crookstown	6/6/01	1,072	13.7
R619	Site 28: North of N22	6/6/01	139	12.2

A maximum 12 hour (0700-1900) flow of 9,100 vehicles was recorded immediately east of Macroom, before the R618 junction. Proportions of HGV’s average around 8-9% on the N22.

The counts were carried out in May and June, which are regarded as neutral months and suitable for such surveys in Ireland.

Traffic flows on the regional roads connecting into the N22 are both significantly lower than on the N22 itself and highly variable between roads. The R582, for example, carries 2,600 vehicles per 12 hour period while the R619 carries less than 150 over the same period. This latter is probably an exceptional case representing a section of very poor horizontal and vertical alignment.

The completed RSI forms were processed to a common zone plan. A validation check has been undertaken on the survey data. The total number of vehicles surveyed at the seven RSI sites during the 12 hour survey period was measured at 13,734 with a total of 6,780 roadside interviews completed equating to an overall sample rate of 45.7%. The sample rates at the individual sites were as follows:

Table 19.5: RSI Sample Rates

Site	12 Hour Count	Total No. Interviews	Sample Rate (%)
Site 25: N22 – West of Ballincollig	4447	1189	26.7
Site 26: N22 – East of Macroom	3619	1289	35.6
Site 27: N22 – West of Ballyvourney	2596	1501	57.8
Site 28: R619 – North of N22	54	41	75.9
Site 29: R585 – North of Crookstown	558	421	75.4
Site 30: R590 – North of Crookstown	1076	776	72.1
Site 31: R582 – North of Macroom	1384	1063	76.8
Total	13734	6280	45.7

The following table provides the same information for the PM peak hour (1700-1800), the busiest single hour of the day and consequently the first hour to be modelled in order to assist in scheme operational assessment.

Table 19.6: RSI Sample Rate (1700-1800)

Site	PM Peak Hour Count	Total No. Interviews	Sample Rate (%)
Site 25: N22 – West of Ballincollig	121	523	23.1
Site 26: N22 – East of Macroom	119	314	37.9
Site 27: N22 – West of Ballyvourney	175	271	64.6
Site 28: R619 – North of N22	4	4	100.0
Site 29: R585 – North of Crookstown	41	47	87.2
Site 30: R590 – North of Crookstown	114	122	93.4
Site 31: R582 – North of Macroom	74	119	62.2
Total	648	1400	46.3

A summary of the travel time survey data is provided in the table below. The primary application of this data was in the coding and validation of do minimum speeds in the traffic model and economic assessment networks.

Table 19.7: Travel Time Survey Data

Route No.	From	To	Road	Distance (km)	Average Speed (kph)
					AM Peak	Inter-Peak	PM Peak
1	Ovens	Ballyvourney	N22	40.8	61	59	59
2	Farnanes	Coachford	R619	9.2	50	48	48
3	Castlemore Br.	Beal na Blath	R585	5.7	65	52	62
4	Crookstown	Carrigeen Xrds	R590	5.1	51	50	49
5	Harnett' s Cross	Inchigeelagh	R584	14.6	65	61	66
6	Toon Br. (R584)	Kilmichael	R587	8.3	86	83	84
7	Macroom	Coachford	R619	12.2	57	57	57
8	West Macroom	Dromree Xrds	R582	3.1	55	60	59

Note: Unless stated start point of route is on N22

These travel time results reveal the lack of variation in travel speeds over the day with inter-peak speeds comparable to those in the peak periods. There is also little variation by direction. Likewise, with the exception of route 6 covering the R587 for which the results are unusually high, there is only a limited range of travel speeds across the eight routes.

An initial analysis of the data obtained from the automatic traffic count (ATC) sites has produced an hourly flow profile and the ratios between AM peak hour, PM peak hour, average Inter-peak hour, 12 hour, 16 hour, 18 hour and 24 hour flows. A summary of this analysis is contained in the table below. These factors are used in the economic analysis in which the entire day is modelled rather than individual hours.

Table 19.8: Analysis Of ATC Data

Time Period	Weekday (M-F) Ratio	Daily (M-Su) Ratio
AM Peak Hour (0800-0900)	0.079	0.066
PM Peak Hour (1700-1800)	0.087	0.084
Average Inter-Peak Hour (0900-1700)	0.058	0.060
12 Hour (0700-1900)	0.757	0.743
16 Hour (0600-2200)	0.926	0.918
18 Hour (0600-0000)	0.978	0.971
24 Hour	1.000	1.000

19.3.1 Trip Matrix Development

AM peak hour (0800-0900), PM peak hour (1700-1800) and Average Inter-Peak (0900-1700) hour trip matrices have been developed from the coded origin/destination survey data. The matrix consists a total of 46 zones. The zoning system used effectively consists of three tiers, detailed area level in Macroom, major settlement level in the counties of Cork, Kerry and Killarney, by county and group of counties beyond this point.

The hourly matrices have been factored to account for the survey sample rate and converted to passenger car units (pcus) by applying a factor of 1.0 for cars and lgvs and 2.0 for hgvs and buses/coaches. The matrices input to the SATURN model, for the purposes of validation, are therefore May 2001 hourly pcu matrices. The hourly pcu format is particularly well suited to the application of SATURN.

The matrix estimation technique is being used as part of the matrix development to take account of unsurveyed trips, in particular those using some of the regional and lesser roads which feed into the N22 but were not included in the O/D survey cordon. It is rarely possible to cover all such entry/exit points of a study network particularly where, as with the current study, prior information is lacking on the traffic volumes using such roads. The matrix estimation technique is commonly applied in such cases.

The model has been through the validation process in which the output base year flows are compared with observed traffic flows from manual and automatic counts. Satisfactory validation is said to have occurred when a target proportion, 85% in DMRB, of model network links meet specified convergence criteria. SATURN uses the GEH statistic as its measure of convergence with values below 5 indicating an acceptable level of convergence.

Full details of the traffic modelling process is provided in the Local Model Validation Report (LMVR) GD00454/RT/010.

19.3.2 Expected Traffic Growth Expansion

Model traffic growth follows NRA's predictions for National (Primary) Roads as given in the National Roads Needs Study. These can be summarised as follows:

Table 19.9: NRA Growth Rates

Vehicle Type	Traffic Growth Rates (% per annum)
	2000-2010	2010-2020	2020 beyond
Light	3.75	1.40	0.46
Heavy	2.76	1.13	0.41

19.3.3 Expected Future Traffic Volumes

The traffic model has been validated against the base year of 2001 and has been accepted for use by Cork County Council. The model has been used to obtain forecast future traffic flows for both full scheme opening (2009) and design (2024) years.

19.4 Economic Analysis of Alternative Schemes

19.4.1 Methodology

The National Roads Authority (NRA) which is responsible for all National Roads in Ireland has adopted the UK Department of Transport’s inter-urban and rural road economic assessment program COBA (Cost Benefit Analysis) version 10 as the standard method of economic evaluation of National Road schemes.

In brief, COBA compares the benefits of a road project, in the form of travel time savings, vehicle operating cost savings and accident savings with the costs, capital and recurrent, of the project. All values are presented in monetary terms allowing a direct comparison to be made between cost and benefits. Those costs and or benefits of a scheme which cannot be quantified in monetary terms, such as social and environmental impacts, have to be assessed outside COBA.

The default price and discount base year for COBA in Ireland as used by NRA is 1996.

19.4.2 Scenarios Modelled

The economic analysis by COBA modelling was not carried out on every route option between Nodes 1 and 16. Due to the large number of these options, individual economic analyses were limited to alternatives with distinctly different alignments, lengths and costs. In addition, during early route assessment, certain routes were identified as unlikely to be the preferred option. Economic analysis of these routes was also not carried out.

It was concluded that a further economic analysis would be undertaken for comparison purposes, if the chosen route were not one of the following improvement options (for which COBA modelling has been carried out):

· East of Macroom: Green, Red, Blue and Yellow.

Modelled in combination with:

· West of Macroom: Yellow and Green/Link/Yellow

It should also be noted that the Yellow and Blue routes east of Macroom have each been modelled with both a dual two-lane, and a two-lane wide single carriageway standard between Macroom and Ballincollig.

Each of these route options have been compared to the Do-minimum scenario over a 20 year period commencing in 2009, the planned opening year for the full scheme.

19.4.3 Scheme Construction and Costs

See Chapter 18 for cost estimates.

For the purpose of comparing the proposed route options, construction of each route is expected to commence in mid 2006 and end in late 2008, with a 10%:40%:50% chronological split between the three years in which construction occurs. It has been assumed that land costs are incurred entirely during the first year of construction.

It has also been assumed that preparation and supervision costs will comprise an additional 13.8% and 5% respectively of the value of the total cost of each option.

For the Do-Minimum situation, it is assumed that cost will consist purely of maintenance of the existing road network - see section 19.4.7.

COBA uses two adjustment factors to take account of variations in prices, the Retail Price Index (RPI) which is a general measure of inflation and the Relative Price Factor (RPF) which applies to construction costs only and reflects the short term volatility of the construction industry.

An RPF of 1.0 has been used given that the change in construction costs in Ireland would appear to have been broadly similar to the general change in prices over the period 1996 to 2001. An appropriate RPI value has been input to the COBA modelling to reflect the 1.14 factor for inflation between 1996 and 2001 (obtained from the Irish Consumer Price Index) that has been used in the calculation of construction costs.

19.4.4 Scheme Modelling

The Do Minimum network consists of the existing road network with the addition of the western end of the Ballincollig bypass.

The geometric characteristics of the network links were obtained from a series of site visits, while broad parameters such as hilliness and bendiness were taken from 1:50,000 maps.

The Do Something network differs from the Do Minimum network only in respect of the inclusion of the appropriate improvement option, each of which consist of five or six links representing the proposed scheme.

Each improvement scheme has been modelled as a single two-lane carriageway with a 60 mph limit. In the cases of the Yellow and Blue routes east of Macroom, the modelling has also included an alternative standard of dual two-lane carriageway with 70 mph speed limit between Macroom and Ballincollig.

The location of scheme junctions varies between alternative routes but the principal junctions are as follows:

· Existing N22 at Ballyvourney

· With the R582 to the west of Macroom

· With the Ballyveerane road to the north of Macroom

· With the R618 and R584 to the south-west of Macroom (except Green route)

· With the R585 and R590 near Crookstown (Blue and Yellow routes)

· With the R619 near Coachford (Green route only) and

· Existing N22/Ballincollig bypass at Ballincollig.

The junctions to the north and west of Macroom have been modelled in COBA as at-grade roundabouts while those to the south and east have been modelled as grade-separated junctions. The precise form of grade-separated junction has not been specified and will be determined at a later stage of the project. It is also possible that the form and size of particular junctions will be revised subsequently.

19.4.5 Traffic

For the Do Minimum network, traffic volumes have been produced by the SATURN traffic model of the N22 current road network. The model and its development are described in full in the Local Model Validation report. For input to COBA link flows from the SATURN model have been used. These values are for the 2009 Opening Year AM (0800-0900) and PM (1700-1800) peak hours and the average inter-peak hour (0900-1700). These together cover a 10 hour day (0800-1800) which has been factored up, using a factor derived from the study ATC data, to 12 hour flows for input to COBA. These flows are summarised for the existing N22 in Table 19.10.

As with the Do Minimum, the output of the traffic model for each of the modelled time periods was combined to give 12 hour (0700-1900) flows for input to COBA for the Do Something Situation. Table 19.10 below details these 12 hour forecasts, as input to COBA, for each option by section for 2009.

Table 19.10: Opening Year (2009) Traffic Flows On The Existing N22 In The Do Minimum Situation

Link No.	From	To	2009 - 12 hr Traffic
181	Ballyvourney	Ballymakeery	6,200
180	Ballymakeery	Ullanes junction	8,000
179	Ullanes junction	Rahoonagh junction	7,700
178	Rahoonagh junction	Coolnacaheragh	7,700
260	Coolnacaheragh	Lissacressig	7,700
261	Lissacressig	Carrigaphooca bridge	7,700
177	Carrigaphooca bridge	R582 junction	7,700
176	R582 junction	Ballyveerane road junction	12,300
175	Ballyveerane road junction	The Square, Macroom	12,500
174	The Square, Macroom	Church Road junction	9,300
173	Church Road junction	Pedestrian crossing, Macroom	11,000
172	Pedestrian crossing, Macroom	R618 junction	11,300
217	R618 junction	R584 junction	10,900
226	R584 junction	Dunisky	10,000
227	Dunisky	Athsollis Bridge	11,400
228	Athsollis Bridge	Kilmurry junction	11,000
146	Kilmurry junction	R590 junction	10,200
141	R590 junction	R585 junction	7,800
133	R585 junction	Farnanes junction (R619) west	9,100
129	Farnanes junction (R619) west	Farnanes junction (R619) east	8,800
123	Farnanes junction (R619) east	Currahaly crossroads	8,800
116	Currahaly crossroads	Ovens bridge	8,900
111	Ovens bridge	Ovens	7,300
274	Ballincollig bypass west		9,700

Table 19.11: 2009 Traffic Flows On The Improved N22 In The Do Something Situation For Each Improvement Option

Route Option	From	To	2009 - 12hr Traffic
West of Macroom: Green/Link/Yellow East of Macroom: Blue	Ballyvourney	North of Ballymakeery	6,200
	North of Ballymakeery	R582 junction	6,100
	R582 junction	Ballyveerane road junction	6,900
	Ballyveerane road junction	R584/R618 junction	6,300
	R584/R618 junction	R590/R585 junction	10,000
	R590/R585 junction	Ballincollig bypass	9,100
West of Macroom: Green/Link/Yellow East of Macroom: Green	Ballyvourney	North of Ballymakeery	6,200
	North of Ballymakeery	R582 junction	6,900
	R582 junction	Ballyveerane road junction	6,400
	Ballyveerane road junction	Coachford	9,200
	Coachford	Ballincollig bypass	7,600
West of Macroom: Green/Link/Yellow East of Macroom: Red	Ballyvourney	North of Ballymakeery	6,200
	North of Ballymakeery	R582 junction	6,100
	R582 junction	Ballyveerane road junction	5,800
	Ballyveerane road junction	R584/R618 junction	5,100
	R584/R618 junction	R619 junction	10,000
	R619 junction	Ballincollig bypass	7,900
West of Macroom: Green/Link/Yellow East of Macroom: Yellow	Ballyvourney	North of Ballymakeery	6,300
	North of Ballymakeery	R582 junction	6,100
	R582 junction	Ballyveerane road junction	6,900
	Ballyveerane road junction	R584/R618 junction	6,300
	R584/R618 junction	R585/R590 junction	10,000
	R585/R590 junction	Ballincollig bypass	9,200
West of Macroom: Yellow East of Macroom: Blue	Ballyvourney	Ballymakeery junction	6,200
	Ballymakeery junction	R582 junction	7,800
	R582 junction	Ballyveerane road junction	8,000
	Ballyveerane road junction	R584/R618 junction	7,400
	R584/R618 junction	R590/R585 junction	10,000
	R590/R585 junction	Ballincollig bypass	9,100
West of Macroom: Yellow East of Macroom: Green	Ballyvourney	Ballymakeery junction	6,200
	Ballymakeery junction	R582 junction	7,800
	R582 junction	Ballyveerane road junction	6,400
	Ballyveerane road junction	Coachford	9,400
	Coachford	Ballincollig bypass	7,600
West of Macroom: Yellow East of Macroom: Red	Ballyvourney	Ballymakeery junction	6,200
	Ballymakeery junction	R582 junction	7,800
	R582 junction	Ballyveerane road junction	6,400
	Ballyveerane road junction	R584/R618 junction	6,000
	R584/R618 junction	R619 junction	10,000
	R619 junction	Ballincollig bypass	7,900
West of Macroom: Yellow East of Macroom: Yellow	Ballyvourney	Ballymakeery junction	6,200
	Ballymakeery junction	R582 junction	7,800
	R582 junction	Ballyveerane road junction	8,000
	Ballyveerane road junction	R584/R618 junction	7,400
	R584/R618 junction	R585/R590 junction	10,000
	R585/R590 junction	Ballincollig bypass	9,200

Flow groups, E-Factor, M-Factor and Seasonality Index are all assumed to remain unchanged from the Do Minimum situation.

Route Option Cross-sections

The NRNS provides guidance on selection of preferred cross-sections for a new route. The NRNS recommends that the route should be designed to provide a “Level of Service” of “D” based on the projected AADT flows 15 years after the route has opened. The “Level of Service” measurement reflects operating speeds, freedom to manoeuvre, the response to traffic interruptions, safety, comfort and convenience of the driver and passengers. The projected traffic flows for the design year (2024) have been obtained and converted into AADT flows for the purpose of establishing a preferred cross-section. Table 19.12 below summarises the projected Annual Average Daily Traffic (AADT) Flows for the year 2024 for the Do Minimum situation.

Table 19.12 Existing and Design Year Annual Average Daily Traffic Flows (AADT) - Do Minimum Situation

From	To	2001 - AADT	2024 – AADT
Ballyvourney	Ballymakeery	6,500	12,400
R582 junction	Ballyveerane road junction	12,600	18,700
Ballyveerane road junction	Macroom centre (east)	13,400	19,100
R584 junction	R590 junction	11,600	18,100
R585 junction	R619 junction	9,500	14,400
Currahaly crossroads	Ovens bridge	9,200	14,100

Table 19.12 includes estimates of 2001 AADT flows, which have been derived from the traffic model. These AADT estimates for the N22 provide a comparison with those from Cork County Council's historic (1990-2000) traffic count data on the study section of the N22, summarised in section 19.1 above. The two sets of AADT estimates are broadly compatible although it is apparent that the study survey data gives higher estimates on the western, Ballyvourney, section and slightly lower estimates at the eastern, Ovens Bridge, section of the N22.

Table 19.13 shows the projected 2024 AADT flows on the routes.

Table 19.13 Design Year Annual Average Daily Traffic Flows (AADT) for Route Options

Route Option	From	To	2024 – AADT
West of Macroom: Green/Link/Yellow East of Macroom: Blue	N22 - Slievereagh	East of Ballyvourney	10,100
	East of Ballyvourney	R582	10,000
	R582	Ballyveerane	11,200
	Ballyveerane	R584	10,300
	R584	R590	16,400
	R590	Ovens	14,800
West of Macroom: Green/Link/Yellow East of Macroom: Green	N22 - Slievereagh	East of Ballyvourney	10,200
	East of Ballyvourney	R582	11,300
	R582	Ballyveerane	10,400
	Ballyveerane	Coachford	15,000
	Coachford	Ovens	12,500
West of Macroom: Green/Link/Yellow East of Macroom: Red	N22 - Slievereagh	East of Ballyvourney	10,200
	East of Ballyvourney	R582	10,000
	R582	Ballyveerane	9,400
	Ballyveerane	R584	8,300
	R584	R619	16,300
	R619	Ovens	13,000
West of Macroom: Green/Link/Yellow East of Macroom: Yellow	N22 - Slievereagh	East of Ballyvourney	10,400
	East of Ballyvourney	R582	10,000
	R582	Ballyveerane	11,200
	Ballyveerane	R584	10,300
	R584	R590	16,400
	R590	Ovens	15,000
West of Macroom: Yellow East of Macroom: Blue	N22 - West of Ballyvourney	East of Ballyvourney	10,100
	East of Ballyvourney	N22 – Carrgaphooca	12,800
	N22 – Carrgaphooca	R582	12,800
	R582	Ballyveerane	13,100
	Ballyveerane	R584	12,100
	R584	R619	16,400
	R619	Ovens	14,800
West of Macroom: Yellow East of Macroom: Green	N22 - West of Ballyvourney	East of Ballyvourney	10,200
	East of Ballyvourney	N22 – Carrgaphooca	12,800
	N22 – Carrgaphooca	R582	12,800
	R582	Ballyveerane	10,500
	Ballyveerane	Coachford	15,300
	Coachford	Ovens	12,500
West of Macroom: Yellow East of Macroom: Red	N22 - West of Ballyvourney	East of Ballyvourney	10,100
	East of Ballyvourney	N22 – Carrgaphooca	12,800
	N22 – Carrgaphooca	R582	12,800
	R582	Ballyveerane	10,400
	Ballyveerane	R584	9,900
	R584	R619	16,300
	R619	Ovens	13,000
West of Macroom: Yellow East of Macroom: Yellow	N22 - West of Ballyvourney	East of Ballyvourney	10,100
	East of Ballyvourney	N22 – Carrgaphooca	12,700
	N22 – Carrgaphooca	R582	12,800
	R582	Ballyveerane	13,100
	Ballyveerane	R584	12,100
	R584	R619	16,400
	R619	Ovens	15,000

The traffic flows in Table 19.13 are taken from the study model for each of the alternative routes.

19.4.6 Accidents

For the Do Minimum situation, observed accident data has been input to COBA to provide a precise calculation of the existing accident rate rather than using national average rates. Accidents in the Do Something situation have been modelled as a function of link and junction types, traffic flows and standard rates and costs. The scheme has been modelled as a modern single two-lane carriageway road with hard shoulder, with the exception of the Yellow and Blue routes east of Macroom (between Macroom and Ballincollig) where dual two-lane carriageway has been modelled in addition to single two-lane carriageway. The appropriate NRA accident rates and costs have been input to COBA to be applied in the evaluation.

19.4.7 Road Maintenance

In the absence of the proposed scheme it has been assumed that the existing road network , together with the Ballincollig bypass, would be maintained to its current standard.

Maintenance costs have been taken directly from the standard NRA value for the appropriate road standards and summarised in Table 19.14 below.

Table 19.14: Road Maintenance Costs for Do Minimum Road Network

Road Type	Maintenance Cost (€/km/year)
Single Two-Lane Road	8,170
Dual Two-Lane Road	15,930

Source: National Road Needs Study Technical Report, Chapter 6 "Cost-Benefit Analysis of Interurban Sections" Table 8 (unpublished). Confirmed by NRA as data to be used in COBA analysis.

As with the Do Minimum road maintenance costing for the Do Something Scenario was derived from the standard NRA value for single two-lane rural roads. The scheme has been assumed to take the per kilometre rate for a single two-lane carriageway road.

The economic evaluation has not, to date, included an assessment of delays to traffic during construction. Consideration will be given to their inclusion, probably through the application of the UK DETR program QUADRO, at preliminary design stage.

19.4.8 Results

COBA outputs a number of economic performance indicators for the scheme under evaluation. The two generally considered most significant are the Net Present Value (NPV) and the Benefit/Cost Ratio (BCR).

The NPV shows by how much, in monetary terms, the benefits of a scheme outweigh the costs. A positive NPV shows that the scheme is currently viable, a negative NPV that it requires amendment or postponement.

The Benefit/Cost Ratio (BCR) allows for the satisfactory comparison of schemes of differing sizes by using scheme cost as a divisor. A value of greater than 1.0 indicates the economic viability of the proposed scheme.

The results of the evaluation, including NPV and BCR are shown in Table 19.15.

19.4.9 Sensitivity Tests

Sensitivity tests will be conducted on the Preferred Route when confirmed. These tests may include the following:

· 30 year evaluation period

· Reduced and increased base year traffic

· Low and high traffic growth forecasts

· Reduced and increased scheme capital costs

No sensitivity tests have been carried out to date.

19.4.10 Conclusions

The results of the comparative economic evaluation, shown in full in Table 19.15, can be summarised as follows:

The best economic results are obtained with the Yellow alignment west of Macroom and the Red alignment east of Macroom. Together, these alignments give a Net Present Value (NPV) of Euro 41.278m and a Benefit/Cost Ratio (BCR) of 1.40.

All the alternative alignments evaluated produced positive NPVs with the exception of the Green-Purple-Yellow/Yellow (single carriageway) with an NPV of Euro -1.803m and a BCR of 0.984.

The results indicate that for the Blue and Yellow alignments east of Macroom a dual carriageway scheme is slightly more economically attractive than a wide single carriageway. However, this increase in standard to dual carriageway does not result in either Blue or Yellow outperforming the Green or Red alignments.

This comparison of routes has not included an assessment of a Macroom bypass in isolation because such an alternative is effectively independent of the overall scheme alignment and does not, as such, form part of the route selection process. However, an assessment of the construction of a Macroom bypass, both as a first stage of the scheme and in isolation, will be carried out during subsequent analysis.

Table 19.15: Summary Of Economic Evaluation Results, N22 Ballyvourney - Macroom - Ballincollig Improvement

West of Macroom alignment	GREEN/LINK/YELLOW						YELLOW
East of Macroom alignment	GREEN	RED	YELLOW - DC	YELLOW - WS	BLUE - DC	BLUE - WS	GREEN	RED	YELLOW - DC	YELLOW - WS	BLUE - DC	BLUE - WS
E X P E N D I T U R E (€M)
(A) DO-SOMETHING SCHEME COST	111.879	105.962	123.954	113.598	128.906	119.220	106.624	100.707	118.699	108.343	123.651	113.964
(B) DO-MINIMUM - SCHEME COST
MAINTENANCE EXPENDITURE SAVING: (C) - TRAFFIC RELATED	-2.621	-2.473	-3.965	-2.665	-3.878	-2.621	-2.520	-2.373	-3.865	-2.565	-3.777	-2.520
(D) - NON TRAFFIC RELATED
PRESENT VALUE OF COSTS PVC = A - B - C - D	114.500	108.436	127.920	116.264	132.784	121.840	109.144	103.080	122.564	110.908	127.428	116.484
B E N E F I T S (€M)
(E) TIME - LINK TRANSIT	146.488	144.097	149.355	132.856	154.136	138.426	148.992	152.262	158.872	142.372	163.767	148.057
(F) TIME - JUNCTION DELAY	-16.286	-15.389	-14.465	-14.657	-14.352	-14.544	-16.560	-16.112	-15.482	-15.676	-15.361	-15.557
(G) VEHICLE OPERATING COSTS - LINKS	-7.447	-3.689	-20.708	-14.111	-17.032	-10.741	-9.326	-6.309	-22.862	-16.263	-19.271	-12.979
(H) ACCIDENTS - LINK AND JUNCTION COMBINED	13.182	13.671	22.102	10.371	22.763	11.539	13.411	14.517	23.232	11.501	23.829	12.606
(J) CHANGES IN USER COSTS DURING CONSTRUCTION
(K) CHANGES IN USER COSTS DURING MAINTENANCE
PRESENT VALUE OF BENEFITS PVB = E + F + G + H + J + K	135.938	138.692	136.285	114.461	145.516	124.681	136.517	144.358	143.761	121.934	152.963	132.126
NET PRESENT VALUE NPV = PVB - PVC	21.438	30.257	8.365	-1.803	12.732	2.840	27.373	41.278	21.197	11.026	25.534	15.642
BENEFIT/COST RATIO PVB / PVC	1.187	1.279	1.065	0.984	1.096	1.023	1.251	1.400	1.173	1.099	1.200	1.134

Notes: Values in €M in 1996 prices and discounted to 1996.

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