Transport Appraisal Approach

Overview

The approach to transport appraisal will be unique to each LDP, given each area will have its own set of challenges and risks which will influence spatial strategy development and delivery. There is no one size fits all for the appraisal and the approach is dependent on the location, scale and type of development, delivery risks and the potential impact on the Strategic Transport Network.

The local network can also be appraised or included, using appropriate tools and can be appraised at the same time as the Strategic Transport Network. However, Transport Scotland is focused on the impact on the Strategic Transport Network.

Planning authorities should contact Transport Scotland at the earliest opportunity to scope the appraisal approach, discuss appropriate modelling tools to use (if required) and reporting required. An authority should come prepared for this discussion, potentially having information on strategy options, scenarios, key constraints and opportunities and any potential risks. This engagement should continue throughout the plan process.

Transport Scotland’s Land-use And Transport Integration in Scotland (LATIS) service is available to provide quantified evidence and this can assist with transport appraisals. The service is operated by Transport Scotland to meet the appraisal and modelling needs of the Scottish Government, project teams within Transport Scotland and external organisations. LATIS includes elements such as models, planning support and data collection. Planning authorities should contact Transport Scotland directly if they wish to access LATIS models or data to support appraisals.

It is expected that the transport appraisal will inform and align with the SEA Report and the Delivery Programme.

Appraisal Levels

This section explains the appraisal levels that may be appropriate, depending on the level of risk associated with plan delivery, location and scale of development and potential type and scale of transport mitigation measures proposed. There are three levels: low, medium or high. These are summarised in Figure 8 on page 27.

It may be suitable to amend the approach and/or move level as more information is gathered, or if the spatial strategy changes, and flexibility in approach may be required where circumstances dictate. Different approaches could be undertaken for different geographical areas within an authority boundary. Authorities may also work together to undertake an appraisal, if appropriate and discussed with Transport Scotland.

Planning authorities are expected to consider potential cross-boundary transport impacts arising from spatial strategy options or developments within their own boundaries, where these affect strategic transport infrastructure in adjacent authorities. Authorities may also wish to appraise cross-boundary impacts on local infrastructure in neighbouring areas, but this does not need to be discussed with Transport Scotland.

Agreement from Transport Scotland on the appraisal level adopted by a planning authority can be provided in formal correspondence, thus ensuring a mutual understanding of the appraisal and key requirements. This provides transparency to the process and ensures that all involved understand their role. Further discussions on appraisal stages, inputs, scenarios and outputs are recommended.

Depending on the level of risk associated with plan deliverability, scale and location of development, and the appraisal level most suitable, it may be appropriate to follow Scottish Transport Appraisal Guidance (STAG) principles. These include identification of problems and opportunities, development of Transport Planning Objectives, option generation and sifting, consideration of Environment; Climate Change; Health, Safety and Wellbeing; Economy; and Equality and Accessibility. Further details are available in the STAG Managers' Guide.

A high-level appraisal will typically be expected to follow these principles to a higher degree. City Deal proposals and other funded infrastructure projects and how to include them in the appraisal should be discussed with Transport Scotland as Deal projects and timescales can evolve.

Place-based principles such as local living and low car neighbourhoods should be considered reflecting NPF4 Policies 13 (Sustainable Transport), 15 (Local Living and 20-minute neighbourhoods) and 18 (Infrastructure First) for all appraisal levels.

It is recognised that land may become available for development unexpectedly that is not allocated within an LDP, classed as windfall. In these circumstances, it is acknowledged that transport modelling and the spatial strategy cannot capture all possibilities. It is suggested if modelling has been undertaken and such a site/s is submitted for planning consent, the model could potentially be re-run with the site/s added, if deemed necessary.

Low Level

A Low level appraisal relates to the lowest levels of risk to plan deliverability. Also, potential infrastructure measures that are considered unlikely to have a notable impact on the Strategic Transport Network, or where interventions could be readily accommodated, are already contained within current national transport investment plans and are designed in sufficient detail and have a delivery pathway.

Medium Level

A Medium level appraisal should be considered where there is an anticipated impact of the plan’s spatial strategy or options on the Strategic Transport Network either from an individual development or cumulatively. This level of appraisal requires a qualitative and quantitative approach and may require the use of modelling tools.

High Level

A High level appraisal should be undertaken where there is likely to be a significant impact on the Strategic Transport Network from individual or cumulative developments and there is a need for significant transport mitigation on or affecting the Strategic Transport Network that does not form part of current national transport investment plans. This level of appraisal requires a largely quantitative approach and the use of localised and area-wide/regional or strategic modelling tools, alongside initial preliminary design and feasibility work.

Low Level Appraisal

A Low level appraisal is likely to be required where:

  • Potential demand is deemed to be unlikely to have a notable impact on the Strategic Transport Network; or
  • Required interventions on or affecting the Strategic Transport Network are minimal and can be readily accommodated; or
  • Required interventions on or affecting the Strategic Transport Network are contained within current national transport investment plans and are designed in sufficient detail and have a delivery pathway.

The level of detail provided, mainly or solely using a qualitative approach, should mean that it is possible to:

  • Provide the rationale for the land use scenarios which should be in line with the sustainable travel and investment hierarchies.
  • Justify that there is no significant or cumulative impact to the Strategic Transport Network or that any impact can be sufficiently accommodated on the existing network or through targeted deliverable measures, or at the development management stage.

A Low level appraisal should consider:

  • Sustainable Investment Hierarchy (with supporting narrative).
  • Sustainable Travel Hierarchy (with supporting narrative).
  • Statutory Impact Assessments – qualitative assessment.
  • Alignment with relevant NPF4 policies.
  • Contribution to NTS2 outcomes and STPR2 Recommendations.
  • Contribution to CCPU ambition to reduce car kilometres travelled.
  • Initial feasibility work, if necessary, to confirm deliverability to indicated line / layout / land take.

Supporting analysis and tools are available to facilitate the consideration of the impact on the surrounding transport networks, mode shift and potentially on cross-boundary issues. This may include:

  • Qualitative methods.
  • Localised existing up to date modelling / GIS.
  • Information developed from the SEA Report.
  • Information from existing Transport Assessments.
  • Existing data knowledge (for example, demographics, network and service timetables, Census, Transport and Travel in Scotland (TATIS), Scottish Household Survey (SHS), Scottish Transport Statistics).
  • Land use planning data.

Examples of transport mitigation may include:

  • Station enhancements (localised access and other improved facilities).
  • Site specific improvements (localised – traffic signals, junction amendment / widening) which can be determined fully at the development management stage.

This level of appraisal may identify individual and / or package(s) of transport mitigation that are required to support the plan and include consideration of realistic alternative options, if applicable.

Medium Level Appraisal

A Medium level appraisal is likely to be required where:

  • There is an identified impact to parts of the Strategic Transport Network.
  • The potential impact may require an intervention to be considered which may have consequences on the Strategic Transport Network.
  • Significant change in land use has been previously unaccounted for in development plans and is not fed into current national transport investment plans.
  • The failure to identify potential deliverable transport mitigation options could impact on the ability for plan proposals to be delivered.

The appraisal should demonstrate that the economic, environmental and safety issues associated with the solution have been identified and, where appropriate, mitigation proposed.

A Medium level appraisal may require modelling tools, such as localised or area-wide multimodal transport models where appropriate, which will facilitate the consideration of the impact of the different transport mitigation options on the surrounding transport networks, mode shift and potentially on cross-boundary issues.

The level of detail, provided through qualitative and quantitative appraisal, should mean that it is possible to:

  • Provide the rationale for the land use scenarios and further, more detailed, consideration of the transport mitigation.
  • Justify that any impact to the Strategic Transport Network can be sufficiently accommodated on the existing network or through targeted deliverable measures and does not compromise safety on the network.

A Medium level appraisal should consider:

  • STAG principles and / or assessment criteria.
  • Sustainable Investment Hierarchy (with supporting narrative).
  • Sustainable Travel Hierarchy (with supporting narrative).
  • Statutory Impact Assessments – qualitative assessment.
  • Alignment with relevant NPF4 policies.
  • Contribution to NTS2 outcomes and STPR2 Recommendations.
  • Contribution to CCPU ambition to reduce car kilometres travelled.
  • Initial feasibility work to confirm deliverability to indicated line / layout / land take.
  • Delivery pathway.

Supporting analysis and tools are available to facilitate the consideration of the impact and any mitigation measures on the surrounding transport networks, mode shift and potentially on cross-boundary issues. This may include:

  • Available models and software (for example junction, network, public transport).
  • Accessibility analysis, GIS, TRACC.
  • Information from existing Transport Assessments.

Modelling and analysis parameters and scenarios, and phasing and delivery of allocations, should be considered and agreed in advance with Transport Scotland.

Examples of transport mitigation may include:

  • Ferry or rail terminal capacity enhancements (localised marshalling and/or car park enhancement, access and other improved facilities).
  • New junction or improvements to multiple junctions or significant improvements to single junctions on single carriageways.

This level should identify individual and / or package(s) of transport mitigation that are required to support the development plan and include consideration of realistic alternative options, if applicable.

High Level Appraisal

A High level appraisal is likely to be required where:

  • There are significant land use changes which present a significant impact to locations on the Strategic Transport Network that require to be mitigated.
  • There is a need for significant transport mitigation options on or affecting the Strategic Transport Network that do not form part of current national transport investment plans.

The appraisal should provide quantified rationale and confirm the principle of deliverability, considering the cumulative impact of development, and initial preliminary design and feasibility work (commensurate with the extent of change to, or effect on, the Strategic Transport Network emerging from the plan preparation process). It should also identify the line / layout and land take of relevant mitigation.

A High level appraisal requires the use of localised and area-wide / regional or strategic modelling tools. In determining and designing appropriate mitigation measures, cognisance of relevant applicable design guidance and any future business case or delivery processes will be required.

Consideration should be given to the requirement for Community Needs Assessments (if upgrading a ferry terminal / port / harbour or increasing ferry services) and Network Rail Investment in Stations Guidance (if a new rail station is proposed).

The level of detail, provided through a largely quantitative appraisal, should mean that it is possible to:

  • Provide the rationale for the land use scenarios and further, more detailed, consideration of the transport mitigation.
  • Demonstrate that the economic, environmental and safety issues associated with the solution have been identified and, where appropriate, mitigation proposed.
  • Undertake technical development, design and feasibility work in order to: confirm that there is an acceptable technical solution; identify land that has to be safeguarded within the plan to procure the solution; and provide a suitable delivery pathway taking cognisance of current investment priorities.

A High level appraisal should consider:

  • STAG principles and / or assessment criteria.
  • Sustainable Investment Hierarchy (with supporting narrative).
  • Sustainable Travel Hierarchy (with supporting narrative).
  • Statutory Impact Assessments – qualitative assessment.
  • Alignment with relevant NPF policies.
  • Contribution to NTS2 outcomes and STPR2 recommendations.
  • Contribution to CCPU national ambition to reduce car kilometres travelled.
  • Initial feasibility work to confirm deliverability to indicated line / layout / land take.
  • Delivery pathway.

Supporting analysis and tools are available to facilitate the consideration of the impact and any required mitigation on the surrounding transport networks, mode shift and potentially on cross-boundary issues. This may include:

  • Available models and software (for example junction, network, public transport).
  • Accessibility analysis, GIS, TRACC.
  • Information from existing Transport Assessments.
  • Cognisance of the broad principles of the Design Manual for Roads and Bridges (DMRB) and Project Acceleration in a Controlled Environment (PACE) (as required).
  • Consideration of Community Needs Assessments and Network Rail Investment in Stations Guidance (as required).

Modelling and analysis parameters and scenarios, and phasing and delivery of allocations, should be considered and agreed in advance with Transport Scotland.

Examples of transport mitigation may include:

  • New rail station.
  • Increased train capacity services (frequency / stopping pattern amendments / platform extensions).
  • Upgrade to ferry terminal / port / harbour.
  • Increased ferry services (frequency / timetable amendments) and/or additional vessels.
  • New at grade or grade separated junction on the dual carriageway or motorway network.
  • Significant junction upgrades and capacity enhancements.

This appraisal level should identify individual and / or package(s) of transport mitigation options that are required to support the development plan and include consideration of realistic alternative options.

Transport Appraisal Reporting

Reporting to support the transport appraisal is dependent on the approach undertaken, which is directly informed by the nature and scale of proposed development and potential impact on the Strategic Transport Network. As noted in the Overview of this section, Transport Scotland can advise on the level of reporting required. Reporting should be proportionate to the appraisal approach and potential impacts and may cover:

  • Statement(s) to confirm there is considered to be no / low impact on the Strategic Transport Network and the supporting evidence justifying this approach.
  • A transport appraisal chapter in the Proposed Plan.
  • Site specific information and appraisal outcomes within settlement statements.
  • Separate DPTAG report.

Modelling requirements and how this feeds into the appraisal and reporting can be discussed with Transport Scotland. Modelling work may be audited by Transport Scotland and its consultants.

Correspondence with Transport Scotland regarding the appraisal and its reporting should be clear, concise, and ideally delivered in a timely and consolidated manner, rather than in a piecemeal fashion. A final report should be issued to Transport Scotland. Reporting should clearly outline the rationale for the approach taken and accordance with national policies and the sustainable travel and investment hierarchies, conclusions of the appraisal, and how the appraisal will influence the Proposed Plan and Delivery Programme.

Agreement should be reached with Transport Scotland before transport mitigation proposals identified within the transport appraisal for the Strategic Transport Network are taken forward and included in an LDP. Network Rail must also be consulted on proposals which have an impact on rail infrastructure.

Delivery Programme

The Delivery Programme is as important as the plan itself, with LDP Guidance providing further information on what should be included.

Engagement with Transport Scotland is recommended to ensure any key performance indicators established at the outset of the transport appraisal are included and monitored as the plan is implemented.

The transport appraisal should feed into the preparation of the Delivery Programme and may also be required to underpin a developer contribution strategy for the infrastructure identified. Therefore, not undertaking an appraisal, risks the outcomes of the plan being achieved.

Where the impact on the Strategic Transport Network comes directly from a development or number of developments, planning conditions or developer contributions may be sought for improvements. This should be made clear within the development plan and Delivery Programme and take cognisance of relevant planning policies, advice and guidance available at that time.

A clear route to delivery should be identified for all sites and proposals, with the Delivery Programme identifying what infrastructure is required, when it is to be delivered and by whom, including details on timing, phasing and cost, and any contribution mechanism or other funding stream. It is vital that consideration be given to viability to ensure that the site and the spatial strategy are deliverable.

It is noted that the delivery and performance of development plans is not the sole responsibility of the planning authorities. Discussions between the planning authority, developers, Transport Scotland (where appropriate), relevant Regional Transport Partnerships and other key stakeholders (for example public transport operators) should be undertaken to agree the necessary requirements. The latest guidance on developer obligations should also be consulted.

Further assessment will be required before any strategic infrastructure can be confirmed as viable. This should follow the relevant business case, DMRB and PACE processes and other guidance where applicable.

In accordance with LDP Guidance, land should only be safeguarded for new trunk roads, rail and ferry infrastructure where approved by Transport Scotland and where it has a clear funding and delivery pathway identified and agreed in the Delivery Programme.

Resources and Timescales

It is recognised that undertaking a transport appraisal may be time-consuming, subject to the appraisal level and may require additional resources. This should be factored into any development plan preparation timetable to ensure the appraisal is completed in sufficient time to inform the Proposed Plan.

Planning authorities are encouraged to use existing relevant evidence, where appropriate, to assist in minimising timescales and resources. Nonetheless, following the approach set out within this Guidance will ensure potential areas of difficulty or conflict will be fully examined before critical decisions are taken.

Transport Scotland will offer advice on appraisal and modelling tools and also feedback and comment on proposals as they evolve through engagement with planning authorities at each stage of preparation of development plans. This will contribute to keeping appraisals proportionate and associated resources and timescales to a minimum. Modelling work may also be required to be audited by Transport Scotland consultants, and this should be factored into appraisal preparation. There may be circumstances where developer-led assessments, which have been appropriately audited, can feed into the DPTAG appraisal.

Development Management

Planning Circular 3/2022: Development Management Procedures provides guidance on the procedures governing applications for planning permission and an overview of the development management system.

Network Rail is responsible for owning, operating, maintaining and developing rail infrastructure. Developers must therefore consult Network Rail separately on planning applications which have an impact on rail infrastructure.

Transport Scotland is responsible for the safe and efficient operation of the trunk road network and ensures that the interests of all users are protected whilst at the same time addressing climate change through sustainable practices and policies and supporting essential economic development. Transport Scotland’s role in development management is outlined in Transport Assessment Guidance.

The planning system seeks to minimise the occurrence of development coming forward at the Development Management stage that is contrary to the development plan or has not been adequately appraised during the preparation of LDPs.

For a proposed development consistent with an adopted LDP that has been appraised using the methodology outlined in this Guidance, any significant and cumulative transport issues should have already been identified, enabling any developer contribution or infrastructure delivery requirement to be clearly known and understood. It is considered that the development management process will be smoother if any cumulative mitigation is identified in the transport appraisal and LDP, enabling this to be understood prior to the submission of an application.

Transport Assessment

Transport Assessment is the process of defining transport proposals and designs based on specific proposals for development or infrastructure. It is at this stage that a more detailed assessment of travel demand on local and strategic networks as required, can be determined and proposed transport solutions can be finalised in a comprehensive manner. The Transport Assessment is intended to quantify the impact of development(s) and demonstrate, through the application of the Sustainable Travel Hierarchy, and by employing a range of measures, how those impacts can be effectively mitigated or managed. 

The Transport Assessment should be undertaken at planning application stage and is not a requirement of the LDP or transport appraisal, however existing assessments may provide information that will be useful to inform the appraisal. It is noted that Transport Scotland is not seeking individual/local site mitigation as part of the transport appraisal; this is considered at development management stage. Early engagement with Transport Scotland is recommended to confirm requirements, and planning authorities should allocate resources for this accordingly.

Detailed information on conducting a Transport Assessment can be found in the Transport Assessment Guidance.