Travel Choices for Scotland: Strategic Roads Review

1 Introduction

A2.1 A key objective of the Strategic Roads Review was to develop a clear and open framework to appraise and inform the prioritisation of trunk road investment proposals. To meet this objective The Scottish Office/Scottish Executive Development Department consulted upon and developed a New Appraisal Methodology (NAM) along the lines of similar work undertaken by the Department of Environment Transport and the Regions in England. The NAM is broadly based and takes account of five criteria:

• Integration
• Economy
• Safety
• Environment
• Accessibility

A2.2 A fundamental aspect of the NAM was the development of an Appraisal Summary Table (AST). This is a two page summary (see Appendix B) of the application of the NAM to a proposed road improvement scheme in terms of the main economic, environmental and social impacts of the scheme. As part of the review, ASTs have been completed for 20 options in the portfolio of major trunk and strategic road schemes which the UK Government inherited in May 1997.

A2.3 This document is designed to be read in conjunction with a completed AST in order that the reader may interpret the Appraisal framework.

A2.4 The Strategic Roads Review ASTs are set out in Annex 4.

2 Purpose of the AST

A2.5 The purpose of the AST is to make the appraisal process transparent and give decision takers a clear, systematic and consistent basis on which to found their decisions about which road schemes should proceed.

A2.6 In developing the AST regard has been given to the need to:

• understand the problem and ask what priority it deserves;
• identify a range of options;
• appraise options to determine the extent to which they meet the Executive's objectives as cost effectively as possible - given the need for benefits to outweigh costs across the spectrum of the criteria and for schemes to represent good value for money.

3 Trunk Road Review Appraisal Criteria

A2.7 The AST summarises the key consequences of a proposed trunk road scheme against 5 criteria. It presents information derived from established techniques that are used to appraise the environmental, economic and social consequences of trunk road schemes. In each case the information reflects the net effect of the trunk road scheme against each of the 5 criteria compared with a scenario without the road scheme. The information is presented in a way that does not give prominence to any one type of effect, or to those benefits expressed in monetary terms compared with those which cannot be measured in this way.

A2.8 The criteria have been divided into a number of sub-criteria and indicators, reflecting the wide variety of impacts arising from schemes. (see table opposite)

A2.9 For each of these, the impact of a road scheme may be expressed in the following ways:

• Qualitatively - using words to describe the main impacts;
• Quantitatively - using numbers to measure the scale of the impacts; and as a
• Summary NAM appraisal - using either a 3 or 7 point textual ranking.

A2.10 Detailed guidelines have been used for each of the criteria to determine what information should be included in the AST. Every effort has been made to ensure that the AST includes all significant impacts. However it is for decision takers to make judgements about the relative value to be put on the individual criteria.

A2.11 This approach marks a fundamental change in the way in which road schemes are considered. It makes the underlying problems and consequences of each scheme more explicit. It assists the comparison and ranking of schemes, particularly where positive impacts have to be traded off against different and negative ones. It does this in a way which attempts to give all impacts equal prominence.

Summary Nam Appraisal

A2.12 The summary NAM Appraisal column of the AST provides a single indication of the impact of the scheme on each criterion/ sub-criterion/ policy area/ indicator.

A2.13 Established practice suggests that monetary values can be used reliably to estimate benefits to road users in the form of reductions in journey times, vehicle operating costs and accidents. Monetary values are also used to estimate the costs of the scheme and construction and maintenance delays. All of these monetary values are expressed as present values. The present value of benefits (PVB) and present value of costs (PVC) are calculated by separately discounting the benefits and costs that arise in future years from the date of scheme opening. These values are expressed in 1994 prices in £m, discounted at 6% and summed over 30 years to a present value base year of 1994.¹³

A2.14 The summary NAM Appraisals are as objective as possible, even where such quantified data cannot be used. In the case of the Environment (except Air Quality and Noise) and the Accessibility Criteria, these use the following 7 point scale:

• negative large;
• negative moderate;
• negative slight;
• neutral;
• positive slight;
• positive moderate;
• positive large.

A2.15 An additional ranking, 'negative very large,' is available where environmental impacts may be deemed to be exceptionally severe. A scale in words rather than numbers has been used to avoid implying a direct comparison between types of impact which are not directly comparable.

A2.16 The methods for deriving the 7 point textual rankings for water and the landscape indicators of geology, ecology, visual impact, agriculture, heritage and landscape character have been produced in consultation with SEPA, Scottish Natural Heritage and Historic Scotland and these and other aspects of the NAM have also been subject to public consultation. For each scheme a detailed appraisal has been made of the impacts. In certain cases, due to lack of data, it has not been possible to apply the New Appraisal Methodology in full but the general principles have been followed. The 7 point scale has also been used for the Integrated Transport and Social Inclusion Indicators to demonstrate measurable differences between the impacts of different schemes in these areas.

A2.17 A simpler 3 point textual ranking of:

• positive;
• neutral; and
• negative

has been used for the Summary NAM Appraisal of the Land Use Planning and Local Economic Development indicators of Integration as well as the Economy and Safety criteria and the Noise and Air Quality sub-criteria of Environment. This reflects the extra difficulty in assessing impacts against these to the finer level of detail of a 7 point scale. (The principles of the appraisal of Air Quality have also been established in consultation with SEPA).

4 Structure Of The Appraisal Summary Table (AST)

A2.18 The remainder of this document explains the structure of the AST and the information which is presented in the AST. A blank AST is reproduced at Appendix B.

Scheme Name - Option - Capital Cost

A2.19 The first part of this box shows the number of the existing trunk road and the name of the scheme. This normally corresponds with the problem area(s) through which the existing road passes. A glossary of terms is included at the end of this document.

A2.20 The second part of the box describes which particular solution or option for improvement of the road the AST applies to. This uses the following summary description of the scheme:

• the length of the scheme in kilometres;
• the carriageway standard;
• whether it is an on-line or off-line scheme; and
• any other pertinent information about the scheme.

A2.21 An on-line improvement scheme refers to a scheme which takes the route of an existing road and an off-line scheme refers to a scheme which takes a different route from the existing road, e.g. a typical bypass scheme. The carriageway standard refers to a single or dual carriageway, the number of traffic lanes provided and whether the scheme is an all-purpose road or a motorway. For example, a D2M road is a Dual carriageway, with 2 lanes in each direction, built to Motorway standard.

A2.22 The third part of the box shows the financial cost of the scheme, exclusive of VAT, estimated as at the second quarter of 1998. The financial costs of the scheme include land acquisition, scheme preparation, contract supervision, construction and maintenance costs.

Problem

A2.23 This box describes the main problems experienced with the existing road which the proposed road improvement scheme is intended to address. As far as possible problems are expressed in terms of the various sub-criteria included in the AST. For most schemes, data is included for the existing road as regards:

• the purpose of the existing trunk or strategic road;
• the average daily number of vehicles using the road;
• the percentage of heavy goods vehicles (HGV's);
• the commuter factor (CF) representing the ratio of peak to off-peak flow;
• and for proposed bypasses:
• the population of the relieved settlement(s).

5 Integration

A2.24 The concept of Integration is incorporated in the Strategic Roads Review at two levels.

• Firstly, the options under appraisal must reflect an integrated approach to transport provision. For the Strategic Roads Review this is tackled in two ways. Initially, the options being appraised were re-considered to ensure that their development represents the best solution to existing and future transport needs; this to test their likely success against a future multi-modal scheme assessment methodology. In this respect, a consultation exercise was conducted to consider the views of transport industry/user interests (see paragraphs A2.27-A2.28). Next the options were considered in terms of their interaction with other modes. For the review examples of the type of characteristic looked for include schemes which facilitate travel by bus or improve bus access to other transport options such as railheads, ferries and ports, airports and so on. Again the consultation exercise assisted in this aspect by feeding in the views of public transport operators to the process of the Review.
• Secondly, the Integration criterion involves consideration of the interactions within and between four important policy areas in the process of developing national transport infrastructure. These are: Integrated Transport, Land Use Planning, Social Inclusion and Local Economic Development. The appraisal of a proposed scheme's impacts on each of these policy areas is set out below.

Integrated Transport

A2.25 The detailed methodology adopted for the Strategic Roads Review brings out the impact of the potential scheme in terms of its facilitation of non-car based transport, including regional and local public transport, and in terms of its facilitation of connections between other modes including Non-Motorised Use (NMU) links.

A2.26 The results are applied to NAM scoring parameters to bring out a potential scheme's impacts on integrated transport. A 7 point textual scale is used and the score is recorded in the Summary NAM appraisal column for the Integration: Integrated Transport Indicator. The associated Qualitative Comments reflect the contribution which the proposed infrastructure will make towards providing improved choice in travel between transport modes.

A2.27 To further inform consideration of the integrated transport issue, 23 organisations, representing a cross-section of transport industry interests, were asked about the scope for public and freight transport infrastructure and operational improvements which might be implemented along the transport corridors containing the schemes under review. They were asked to answer this both on the basis of the review scheme proceeding and on it not proceeding.

A2.28 The main points in the responses were:

• high transport costs impact on rural areas;
• higher investment was required on road maintenance and in the provision of new road links (eg M8, M74, A80, M77, A8000);
• road would continue to be the predominant mode for freight transport, although it was recognised that there was scope for transferring some freight to rail;
• there was a need for better road and rail connections (including public transport connections) to important transport facilities such as airports and ports;
• an indication that transport operators would be willing to enter into discussions on how public transport might benefit from the major trunk road improvements approved following this review.

Land Use Planning

A2.29 This policy area of Integration appraises the extent to which the proposed trunk road scheme integrates with national, regional (Structure), and detailed (Local) planning policies.

A2.30 The Integration: Land Use Planning policy area of the New Appraisal Methodology recognises that national planning policy and transport policies and plans are features of statutory Structure and Local Plans. Thus the land use planning aspects of the NAM are appraised as follows against Structure Plans and Local Plans and the national and transport planning aspects of these.

A2.31 Structure Plans: the appraisal is based on all land use policies (including the transport planning policy aspects) relevant to the scheme in National Planning Policy and Structure Plans.

A2.32 Local Plans: the appraisal is based on land use policies relevant to the scheme in Local Plans, including transport policies and plans excepting those which appear in national planning policies and Structure Plans (this to avoid double counting).

Methodology

A2.33 The methodology used to appraise the integration of the trunk or strategic road scheme with LU plans and policies is as set out below.

A2.34 For each Plan (Structure and Local) an overall summary NAM appraisal is given on the 3 point scale taking account of the balance between policies and plans which are facilitated, those which are hindered, and those which are unaffected as follows:

• the impact of the scheme is appraised as Positive if more policies are facilitated than hindered, Negative if more are hindered than facilitated, or neutral. Finer levels of appraisal are not required for this policy area;
• the appraisal should not be mechanical; marginal differences should be ignored and key policies should be given greater weight as should those which are more geographically specific;
• as recommended in DMRB 11.3.12.4 Para 4.5, greater weight should be given to up-to-date policies in adopted plans but emerging plans should not be ignored. Little weight should be given to non-statutory plans and policies.

A2.35 The resulting 3 point textual score is recorded in the summary NAM appraisal column while the qualitative column is used to comment on the currency of LU Plans and any particular benefits to be derived from the scheme under appraisal.

Social Inclusion

A2.36 The New Appraisal Methodology acknowledges that those experiencing social exclusion are less likely to be car users than the population in general and that there is therefore a particular interest in the impact of options on non-car users. To a certain extent this is dealt with in terms of the 'Accessibility' criterion but an overarching view requires to be taken in the policy areas of integrated transport provision as regards Public Transport and Social Inclusion.

A2.37 The appraisal of potential trunk & strategic road schemes therefore includes the extent to which a scheme promotes the use of public and non-motorised transport in order to take cognisance of the interactions between transport and social inclusion. In addition, Social Inclusion considers the status of those geographical areas served by the road in terms of European Objective 1 Area or Priority Partnerships/Social Inclusion Partnerships or equivalent status and whether or not the scheme will assist Public Transport and NMU access to employment, education and health facilities.

A2.38 Again the results from the appraisal of Social Inclusion are applied to NAM scoring parameters to bring out the scheme's impacts on Social Inclusion. A 7 point textual score applies and this is recorded in the summary NAM appraisal column for the Integration-Social Inclusion Indicator.

A2.39 Comments on the effects of the scheme are included in the qualitative column. In the case of Social Inclusion this includes whether or not the road serves a Priority Partnership/ SIP or European Objective 1 Area.

Local Economic Development

A2.40 Some road schemes may have impacts which assist the economic and social regeneration of an area. The significance and balance of these impacts is likely to vary significantly depending on local circumstances and the nature and size of the scheme in question.

A2.41 However, current appraisal techniques are not sufficiently advanced to enable such impacts to be either monetised or expressed as a single quantitative measure. Summary NAM Appraisals are made and qualitative descriptions given for regeneration impacts by making use of information provided by Scottish Executive sources.

A2.42 The impact of a scheme is categorised in 2 ways:-

• whether or not the scheme serves a regeneration/priority area and may have a general potential to help regenerate the area;
• whether or not specific developments in these regeneration priority areas are dependent on the trunk or strategic road scheme.

A2.43 For the summary NAM Appraisal, proposals are categorised as having a potentially beneficial effect if they satisfy 2 criteria:

• firstly, the proposal should serve an area with recognised Area Programme status (such as Assisted Area, European Structural Fund, Rechar II) such that either:
• the road which the proposal would affect passes through the Programme Area and/or there will be a direct link(s) between the area and the road; or
• an access road from a key development site within the area feeds or is intended to feed directly onto the road; and
• secondly the scheme is consistent with the strategy to achieve local regeneration objectives.

A2.44 Proposals which have been categorised as potentially beneficial for a designated regeneration area should, in addition, be categorised as being development dependent if development sites have been identified and there is a high probability that either:

• the trunk road authority would object to the development on the basis of current road infrastructure provision; or
• planning permission is conditional on the transport improvement; or
• investors would not come forward or proceed beyond feasibility in the absence of the scheme.

A2.45 These details are recorded in the qualitative column together with the unemployment rate (UR) for the travel to work area through which the scheme passes. Where the scheme passes through more than one travel to work area, the higher or highest rate has been shown. A 3 point textual score again applies and this is recorded in the summary NAM appraisal column for the Integration: Local Economic Development Indicator.

6 Economy

A2.46 The Economy criterion has 3 sub-criteria:

• journey time savings;
• vehicle operating cost savings (VOC);
• journey time reliability.

A2.47 The methodologies for calculating journey time and VOC savings are set out in the DMRB. As part of the review a new approach has been developed for summarising the impact of the scheme on the reliability of journey times.

Journey Times and VOCs

A2.48 The net present values of the:

• journey time savings; and
• vehicle operating cost (VOC) savings

resulting from the economic appraisal of the proposed scheme are each shown in the quantitative column in £m. The summary NAM appraisal column uses the 3 point scale to summarise the scheme effects of each of these indicators. The relevant summary NAM appraisal column also includes the present value of the savings (for both journey times and VOC) expressed as a percentage of the present value of the scheme costs.

A2.49 These benefits (or disbenefits where they are negative) are calculated by estimating the journey times and VOCs that would occur if the scheme was built compared with estimates of there values without the scheme. The difference in these values represents the benefits or disbenefits of the scheme.

A2.50 The Journey Time qualitative column shows the peak and interpeak journey time changes (in decimal minutes) for trunk or strategic road users in the design year as a result of the proposed scheme.

Reliability

A2.51 At present, an agreed methodology for estimating journey time reliability is not available, although research on this issue is ongoing. The reliability of journey times is considered to be reduced as the flow of traffic on a road approaches its capacity. Flow is measured as the Annual Average Daily Traffic (AADT) and capacity is expressed as a Congestion Reference Flow. This ratio of flow to capacity is described as the stress level of a road (excluding junctions) and has been used as a proxy for journey time reliability. Further advice on stress, including the definition of Congestion Reference Flow, is provided in Volume 5, Part 1, Section 13 of the Design Manual for Roads & Bridges.

A2.52 For the Strategic Roads Review an alternative methodology has been used based on the current availability of Route Profiles for each trunk road in Scotland. These provide Levels of Service which are a measure of the degree of freedom available in dynamic flow conditions. The measurements range from 'F' (traffic at a standstill or stop-go conditions) through to 'A' which represents high amenity, lightly trafficked conditions. Thus Peak and Inter-peak Level of Service condition changes between present and opening year scenarios are used in the AST.

A2.53 A 3 point textual ranking of the proposed scheme's positive, negative or neutral contribution towards reliability of the route is recorded in the summary NAM appraisal column.

A2.54 A brief commentary may be included in the qualitative column about the impact of the scheme on journey time reliability.

7 Safety

A2.55 The qualitative column lists the reduction in:

• the number of fatal personal injury accidents;
• the number of serious personal injury accidents;
• the number of slight personal injury accidents

due to the scheme (over a 30 year period starting from the scheme opening year) compared to the situation without the scheme. This data is derived using the standard methodology for calculating the number of accidents as set out in the DMRB. This normally applies standard accident rates to the modelled traffic network with the scheme and local data to the scenario without the scheme. Where local rates may prove unreliable in the longer term or are otherwise not applicable, default rates may be used in both scenarios.

A2.56 The quantitative column shows:

• the present value of the safety benefits in £m over a 30 year period from scheme opening.

A2.57 Safety benefits are calculated by applying standard value of life figures for fatal, serious and slight injuries to the estimates of the number of fatal, serious and slight personal injury accidents over a 30 year period from scheme opening. This methodology and the standard values of life are set out in DMRB.

A2.58 A 3 point textual ranking of the proposed scheme's positive, negative or neutral contribution towards the safety of the route is recorded in the summary NAM appraisal column. The present value of the safety benefits expressed as a percentage of the present value of the scheme costs is also shown in the summary NAM appraisal column.

8 Summary Of Monetised Cost-Benefit Measures

A2.59 This section of the AST includes four measures used in summarising the monetised costs and benefits of trunk road schemes. These are presented in the normal way assuming National Road Traffic Forecast Central Growth. Also presented are the cost-benefit measures associated with a Zero Growth scenario - these indicate the monetised costs and benefits of the improvement were traffic flows to remain at present levels during the economic life of the improvement. The statistics shown are:

• PVC (present value of costs) - this is the sum of the scheme costs, discounted over 30 years from the scheme opening date, shown in £m and expressed in 1994 prices and values. This figure includes the capital, land acquisition and preparation, contract supervision, and future maintenance costs of the scheme. Where a partial solution could be provided by 'do-minimum' works, the costs of these are deducted to give the total PVC;
• PVB (present value of benefits) - this is the sum of the scheme benefits, as measured through NESA (or equivalent), discounted at 6% over 30 years from the scheme opening date, shown in £m and expressed in 1994 prices and values. These benefits comprise: journey time savings, vehicle operating cost savings and reductions in accidents. The benefits provided by 'do-minimum' works are deducted to give the total PVB;
• NPV (net present value) - this is the difference between the PVB and PVC and is shown in £m;
• BCR (benefit-cost ratio) - this is the ratio of the PVB divided by the PVC.

A2.60 Salient information about the sources of these measures is provided in the adjacent title box.

9 Environment

A2.61 The Environment criterion has been divided into a number of sub-criteria and indicators which broadly reflect the structure of the environmental impact assessment used for trunk road schemes. The sub-criteria and the methodology for dealing with these are as follows.

Noise

A2.62 The Quantitative column includes data on the number of properties that would experience significant increases and decreases in noise levels in the assessment year if the road scheme were built, compared with the situation that would exist immediately before the opening of the scheme (i.e. Scheme c.f. Base). The assessment year is generally defined as 15 years after the scheme is opened (unless traffic levels are higher in another year). Noise levels are measured in dB(A) and a significant change is defined as 3dB(A) or more.

A2.63 The Summary NAM Appraisal column contains the net difference between the numbers of properties experiencing a significant + ve or - ve change in noise by the assessment year, compared with the change in the noise climate without the scheme over the same period (i.e. scheme c.f. do-minimum).

A2.64 This figure provides the best indicator of the incremental impact of the scheme with the data available.

A2.65 The Qualitative column includes any comments about the impact of the scheme on the noise environment including whether or not the scheme will introduce noise impacts to any previously unaffected property.

Global Air Quality

A2.66 The appraisal of global air quality uses carbon dioxide (CO2) as the indicator. The quantitative column gives the estimate of the net change in CO2 between the network with the scheme and the existing or do-minimum network over a 30-year assessment period. The estimates were made using the relevant outputs from the particular traffic/transportation model used for scheme evaluation purposes. The estimates of CO2 are subject to uncertainty, for example as regards the prediction of future vehicle and fuel technology advances. Due to this uncertainty, CO2 estimates are presented in broad ranges on the ASTs.

A2.67 The Summary NAM Appraisal column uses the 3 point scale to indicate whether the impact of the scheme on global air quality is positive, negative or neutral. The qualitative column is blank for this sub-criterion.

Local Air Quality

A2.68 The local air quality appraisal for the Strategic Roads Review has focused on 2 pollutants, NO2 (nitrogen dioxide) and PM10 (fine particulate matter generally under 10 microns in size). These 2 pollutants are currently considered to be of most concern with respect to road transport emissions. As well as being detrimental to human health in their own right, they also act as proxies for other local air quality pollutants. NO2 is measured in parts per billion (ppb) and PM10 is measured in micrograms per cubic metre (µg/m3).

A2.69 The Quantitative column includes data on the net number of properties that experience an improvement or a deterioration in air quality in the year 2005 if the scheme is built compared with the situation in 2005 without the scheme. Changes in the levels of PM10 and NO2 have been forecast in the same terms as their respective objectives set out in the UK Government's National Air Quality Strategy (NAQS). These are used as proxies for changes in air quality.

A2.70 The Summary NAM Appraisal column uses the simple 3 point scale to summarise the impact of the scheme on each of the PM10 and NO2 local air quality indicators.

A2.71 The Qualitative column may provide comments if thresholds and/or NAQS objective(s) are exceeded as follows:

• for schemes where there is an increase in PM10 levels of at least 2µg/m3;
• for schemes where there is an increase in NO2 levels of at least 2ppb and where the improved or new road is above the NAQS NO2 objective of 21ppb.

Water

A2.72 A risk assessment approach has been taken to assess the impact of schemes on water quality and drainage. This has been done because the impact of a scheme on water quality, drainage and flood defence is dependent not only on the sensitivity of the location but also on the following particular factors:

• the detailed design of the scheme;
• the working practices that are operated during construction; and
• the design and effective implementation and management of mitigation/attenuation measures.

A2.73 The approach identifies the scale of risk to water quality and drainage that is posed by each scheme. It does this by assessing the sensitivity of the receiving environment and the potential of the scheme to cause harm. These assessments are then used to determine an initial ranking which will be either neutral or negative (slight, moderate, large).

A2.74 However, when the effect of mitigation is included, this reduces the impact of both new and existing roads on water quality and drainage. Textual rankings are then made on the standard 7 point scale in the summary NAM Appraisal column.

A2.75 In addition the qualitative column provides comments on any particularly sensitive feature(s) affected by the scheme, while the quantitative column indicates the number of highly sensitive features affected.

Landscape

A2.76 The Landscape sub-criterion of Environment includes six indicators which appraise the impact of a road on geology, ecology, visual aspects, agriculture, heritage and landscape character. These have been developed through public consultation. The detailed appraisal methodology has also been subject to the advice and agreement of Scottish Office/Executive statutory advisors for the environment.

A2.77 The approach developed for the geology, ecology, heritage and landscape character indicators is broadly based on the concept of 'environmental capital.' This approach systematically and objectively identifies the features which contribute to each indicator and the impact of the scheme on these features using a set of characteristics. Ideally the approach would use the same characteristics for each indicator. However, slight differences have had to be applied to different indicators, this dependent on the advice and requirements of the relevant statutory advisor for the environment.

A2.78 Features of geology, ecology, heritage and landscape character are appraised against either all or a combination of the following characteristics:

• scale - the geographical scale at which the feature is important (eg local, national, or international);
• importance - the reasons why the feature is important, such as reasons for a designation;
• rarity - the relative abundance of the feature, or its trend in relation to a target level;
• substitutability - whether or not a feature is replaceable within a given time period;
• conservation evaluation - the classification of features into formal categories of conservation importance;
• impact - the impact of the scheme on the feature taking mitigation into account;
• additional mitigation - whether or not further mitigation, over and above that already included in the proposed scheme, might be considered.

A2.79 The written comments recorded for each feature against these characteristics are used to determine the summary NAM appraisal using a textual ranking on a 7 point scale. As noted above, the exact ways in which these are undertaken vary slightly for each of the geology, ecology, heritage and landscape character indicators.

Geology

A2.80 This Indicator is concerned with the impacts of a scheme on natural earth heritage features.

A2.81 The approach taken to summarise the impact of road schemes on geology has been to describe existing earth heritage features using the various characteristics and then state the impact that the road scheme has on each feature.

A2.82 A textual ranking, using the standard 7 point scale, has been given in the summary NAM Appraisal column, depending on the assessment of the conservation importance of each feature and the impact of the scheme.

A2.83 In addition the qualitative column contains comments about any particular aspect of geology affected by the scheme, while the quantitative column records the number of sites involved.

Ecology

A2.84 This Indicator is concerned with biodiversity and important habitats and species.

A2.85 As with geology, the approach taken to summarise the impact of road schemes on ecology/biodiversity has been to describe existing features (i.e. habitats and species) using the various characteristics and then state the impact that the road scheme has on each feature.

A2.86 A textual ranking, using the 7 point scale, has been given in the Summary NAM Appraisal column, depending on the assessment of the nature conservation importance of each feature and the impact of the scheme.

A2.87 In addition the qualitative column contains comments about any particular aspect of ecology affected by the scheme, while the quantitative column records the number of features affected.

Visual Impact

A2.88 The approach used to assess the Visual Impact Indicator of Landscape is based on the effect of the scheme on all affected visual receptors at year of opening. The impacts on all affected visual receptors, whether buildings or outdoor locations, are appraised for their adverse or beneficial effect on a scale of substantial/moderate/slight. Using a weighted multiplier for different types of visual receptor (see below) the overall visual impact of the scheme is scored in terms of 'Visual Impact Units'.

A2.89 The different types of visual receptors used are as follows (weightings shown in brackets):

A2.90 The total number of visual impact units divided by the total number of receptors is converted to a textual ranking on the 7 point scale to give the summary NAM appraisal column score.

A2.91 The appraisal is also undertaken for the situation of the scheme 15 years after opening under summer conditions. This may form a commentary in the qualitative column while the number of visual receptors adversely or beneficially affected is shown in the quantitative column.

Agriculture (inc. Land Use)

A2.92 A different approach is taken to the Agriculture (including Land-Use) Indicator. Here the qualitative column of the AST provides information about the use of Greenbelt, Greenfield and Brownfield land for the scheme being appraised. The quantitative column gives information on the area of Prime Quality and non - Prime Land utilised for the scheme and the %age of Prime to total land required. The Summary NAM Appraisal is based on the impact of the scheme on agricultural units (farms) in terms of the following four factors:

• whether >2 ha of prime land or > 10 ha of non-prime land is affected;
• the viability of existing husbandry;
• the effects of severance in terms of major changes in farm operation;
• the extent of accommodation works required to maintain the viability of farm operation.

A2.93 A textual ranking on the 7 point scale is given in the summary NAM appraisal column depending on the extent to which the proposals improve, cause damage, or are neutral with respect to these factors either singly or in combination.

Heritage

A2.94 This Indicator assesses the impact of a road scheme on the historic environment. The appraisal of the impact of proposals on the historic environment (including historic landscape) involves the following process:

• describing the historic resource potentially affected by the scheme;
• assessing the importance of the resource; and
• assessing the impact of the scheme on the importance and integrity of the resource.

A2.95 A four stage appraisal framework is used:

A2.96 A textual ranking on the standard 7 point scale is given in the Summary NAM Appraisal column. The quantitative column provides the number of features affected, while the qualitative column provides a commentary on the main impacts of the scheme on Heritage.

Landscape Character

A2.97 The approach used for appraisal is a simple application of emerging work on the concept of Environmental Capital in combination with the established process for describing landscape character (both urban and rural). It is a suitable methodology for the appraisal because it builds upon information about landscape character to identify landscape features for appraisal using a set of common criteria. In this way it is possible to consider how successful or unsuccessful mitigation will be in retaining, improving and protecting each of these characteristic features.

A2.98 Landscape is systematically classified into the following features:

A2.99 In appraising the impact of a scheme on landscape character, it is normally possible to consider whether additional, specific mitigation should be considered over and above the design objectives of the scheme proposals. This permits new ideas for mitigation, not expressed through scheme assessment work, to be considered in order to determine whether all measures proposed will be:

• beneficial and cause the scheme to have a positive impact on the landscape;
• essential to neutralise the impact of the scheme proposed on the landscape; or
• ineffective in reducing/minimising the impact of the scheme.

A2.100 In this way all scheme options can be judged on a comparative basis. A textual ranking on the standard 7 point scale has been given in the summary NAM appraisal column depending on the extent to which the proposals improve, cause damage, or are neutral with respect to these features. In addition the qualitative column may be used to comment on any particular aspect of landscape considered of particular importance. The quantitative column is not used.

10 Accessibility

A2.101 This criterion summarises the assessments made of the impacts of the proposed road scheme on journeys which people make in its locality using modes other than cars, vans and lorries. The methodology for making these assessments is set out in Volume 11 of the DMRB. The criterion is divided into 3 sub-criteria:

• impacts on pedestrians, cyclists and other NMU's;
• community severance; and
• access to public transport.

A2.102 Each of these is given a neutral, slight, moderate or large textual ranking, either positive or negative, in the summary NAM appraisal column. For all 3 sub-criteria, this assessment is based on changes in accessibility in the scheme opening year. However for public transport it also takes account of changes in service quality over time.

A2.103 A brief comment is included in the qualitative column about the impact of the scheme on each of the sub-criteria.

Pedestrians and Cyclists

A2.104 This sub-criterion provides a summary assessment of the impact of the proposed trunk road on the journey times of pedestrians and other non-motorised road users such as cyclists and equestrians. It takes account of the number of people affected, the extent of the increased journey times and any delays and changes in travel patterns and amenity faced by these users.

Community Severance

A2.105 This sub-criterion provides a summary assessment of the impact of the trunk road on community severance, as it affects non-motorised modes of transport, particularly pedestrians. It takes account both of the extent of severance and the numbers of people affected.

Public Transport

A2.106 This sub-criterion provides a summary appraisal of the impact of the trunk road scheme on access to public transport services. The summary appraisal takes account of those local public transport routes for which the time taken to access the services, and/or the quality of the access part of the journey are significantly affected by a trunk road scheme. The change in access time combines the number of passengers affected and changes in walking time. The changes in access times and quality are used to determine whether the summary assessment is neutral, positive or negative.