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Transport Research Series
Guide to Transport Assessment for Development Proposals in Scotland

Steer Davies Gleave

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Main Findings

• A Transport Assessment is a comprehensive and consistent review of all the potential transport impacts of a proposed development or redevelopment with an agreed plan to reduce any adverse consequences;
• A Transport Assessment aims to provide information so that decision makers understand how the proposed development is likely to function in transport terms. It should assist in the methods of mitigation designed to reduce adverse transport impacts;
• The importance of Transport Assessment cannot be overstated. Policy initiatives require that new development and redevelopment of existing sites aim to promote more sustainable travel patterns. Preparing a Transport Assessment is part of the process of securing planning permission;
• Assessing the transport impacts in a systematic manner contributes towards understanding how more sustainable travel patterns might be achieved through changing transport behaviour;
• While the submission of a Transport Assessment alongside the planning application will not guarantee that permission will automatically be given, it should ensure that a decision will be made more speedily and be based on an appropriate investigation of the available information.

Background

NPPG 17 "Transport and Planning" was published in April 1999 and places particular emphasis on accessibility to development by public transport, walking and cycling as part of a more integrated approach to planning and transport. To help implement this, NPPG 17 advises that developers should submit Transport Assessments (TAs) alongside planning applications which are likely to have significant travel generating implications. Transport Assessment should build upon and develop the system of Traffic Impact Assessments, but be broader in focus and cover access by all modes of transport.

This research had regard to the draft guide recently produced by DTLR but is tailored to the specific requirements of the Scottish development process. It is the intention to develop a plain English "good practice" Guide for the assessment of development proposals in relation to transport issues.

Methodology

The research involved seven elements:

• Review of relevant Scottish policy and planning guidance.
• Review and assessment of sources of data in Scotland.
• Review of current technical guidance and emerging Transport Assessment procedures.
• Preparation of a draft Guide including procedures for undertaking a Transport Assessment.
• An in-depth consideration of seven case studies to investigate how the proposed procedures might have affected the Transport Assessment undertaken.
• A consultation workshop with representation from local authorities across Scotland and the development industry.
• Finalisation of the Guide taking on board comments from the workshop and the Scottish Executive.

Key Findings

Findings arising from these seven elements are set out below:

• The Scottish Integrated Transport White Paper, Travel Choices for Scotland and the forthcoming Transport Delivery Report for Scotland set the national policy context for Transport Assessments that is implemented via Local Transport Strategies. NPPG 17 and PAN 57 provide the more detailed context;
• Much data exists that may be of use but currently there remain some weaknesses;
• Seven case studies were investigated covering a range of types of development across Scotland. These highlighted how the proposed procedures outlined in the draft Guide may have influenced the TA submitted. The need for early discussions between the developer and planning authority to agree the scope of the TA was noted.
• A useful consultation workshop was held at the Scottish Executive on Tuesday 20 November 2001 with representatives of local authorities, developers and their agents. The draft guide was presented and breakout groups discussed four key issues: scoping a TA; accessibility criteria; mode share targets and implementation and monitoring.

Key points arising from the workshop included :

• We should expect a higher modal shift in urban than rural areas where parking standards are different;
• Large cities are viewed as good at implementing TAs but it is easier for them than rural locations;
• The Guide will be voluntary advice;
• Everyone should use the guide to make a level playing field;
• The TA process should be shorter and cheaper for developers when proposals are policy compliant;
• Commercial developers look at commercial viability first and foremost;
• Most developers must be persuaded sustainability is in their interest;
• Developers should accept that the approach to TA is likely to vary in different planning authorities;
• Development will always generate traffic and the road network must be able to cope;
• If a developer takes a risk and fails to meet modal share targets then mitigation measures will be required.

The Transport Assessment Guide

The main items contained in the Guide include a definition of a transport assessment, its purpose, the Scottish policy context, transport assessments and traffic impact statements and the actual transport assessment process.

• A TA is a comprehensive and consistent review of all the potential transport impacts of a proposed development or redevelopment with an agreed plan to reduce any adverse consequences.
• The purpose of a TA is to provide information so that decision makers understand how the proposed development is likely to function in transport terms. It should assist in the methods of mitigation designed to reduce adverse transport impacts.
• In the Scottish policy context NPPG 17 replaced the system of Traffic Impact Statements(TIAs) with broader Transport Assessments(TAs) that cover access by all modes and provide an opportunity to promote modal shift to more sustainable transport and are intended to ensure that access to significant travel generating developments by non-car modes becomes significantly greater than at present.
• TIAs were designed to ensure that traffic impacts associated with new development would be accommodated by providing extra road capacity to avoid congestion arising. TAs start from the basis of planning for desirable mode shares and reducing the role of car access as much as possible. Car access will still be required and there will remain the need for TIA to be part of a TA.
• The TA process may range from a simple and straitforward one to one that is complex since it must address the transport impacts of alternative modes for a variety of differing types and sizes of development in different locations.

Recommendations

The recommendations about carrying out a TA arising from this research include:

• A TA must provide information to those who will decide whether planning permission should be granted. The exact detail required will depend on the scale of the proposed development and the specific circumstances of the case.
• A simple TA Form should be submitted for all development proposals.
• Larger developments or those with significant transport impacts will require more detail including; an assessment of travel characteristics, a description of the measures which are being adopted to influence travel to the site and a description of the transport impacts of the development and how these are being addressed.
• For larger developments the process is potentially an iterative one, with refinement of the layout design, improving public transport services and so on, leading to regular discussions between the developer and local authority, and possibly other stakeholders, such as RNMMD.
• Developers contemplating a new development or redevelopment should hold scoping discussions with the local authority and Scottish Executive (RNMMD) if it is likely to affect trunk roads as early as possible so as to agree the appropriate transport assessment. It will enable developers to clarify whether the proposal is policy compliant and whether the transport elements of the proposal are likely to be acceptable or whether additional analysis or measures will be required. Mode Share Targets may be agreed at the scoping meeting.
• Scoping discussions should also be used to identify measures needed to promote a wider choice of access to the site particularly by non-car modes, including; improvements or modifications to pedestrian access, improvements or modifications to cycle access, improvements or modifications to public transport services, and addressing residual traffic generation.
• A TA should present all the transport implications of the proposal, including the impact on trunk roads in the vicinity. However, the transport impacts of any development proposal are not always easy to predict, and it is necessary for developers to be given the opportunity to explain how the implications may be different.
• A TA containing more detail will be required where the development or redevelopment is likely to have significant transport implications, no matter the size. The coverage and detail of the Transport Assessment should reflect the scale and likely extent of transport impacts of the proposed scheme.