Transport Assessment
A Transport Assessment is one of the most significant supporting documents for major planning applications across the UK. It provides a comprehensive analysis of the transport implications of a proposed development and is used by highway authorities and planning officers to determine whether a scheme can be accommodated on the local road network without unacceptable impacts on safety, capacity, or accessibility.
Typical Cost
£300 – £5,000+
Turnaround
1 – 6 weeks
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What is a Transport Assessment?
A Transport Assessment (TA) is a detailed technical document that evaluates the transport impacts of a proposed development on the surrounding highway network. It considers all modes of travel including private car, public transport, walking, and cycling. The assessment quantifies the number of trips the development is expected to generate, analyses the capacity of key junctions and road links to accommodate those trips, and proposes mitigation measures where adverse impacts are identified. The scope is governed by guidance in the NPPF and the Department for Transport's Planning Practice Guidance on transport matters.
When is a Transport Assessment required?
Transport Assessments are required for developments that are expected to generate significant amounts of traffic or have a material impact on the highway network. While specific thresholds vary between highway authorities, a TA is generally needed for residential developments of 50 or more dwellings, retail schemes exceeding 800 square metres, office developments over 2,500 square metres, industrial or warehouse schemes above 5,000 square metres, and any development that would have a significant impact on a trunk road or strategic road network. The relevant highway authority should be consulted at pre-application stage to confirm whether a TA is required and agree its scope.
What does a Transport Assessment include?
A comprehensive Transport Assessment includes a description of the site and its accessibility by all modes of transport, a review of relevant transport policy at national, regional, and local level, baseline traffic surveys and analysis of existing highway conditions, trip generation forecasts using an industry-standard database such as TRICS, trip distribution and assignment to the highway network, junction capacity modelling using software such as ARCADY, PICADY, or LinSig, an assessment of impacts on pedestrian and cyclist safety, public transport accessibility analysis, proposed mitigation measures including highway improvements, travel plan measures, or financial contributions, and details of parking provision against the local authority's adopted standards.
How much does a Transport Assessment cost?
Transport Assessments are substantial documents and the costs reflect this. A TA for a medium-sized residential development of 50 to 150 dwellings typically costs between £5,000 and £15,000, depending on the number of junctions to be modelled and the complexity of the highway network. Large-scale developments with multiple access points, strategic road network impacts, or microsimulation modelling requirements can cost £20,000 to £50,000 or more. Traffic survey data collection adds further cost, typically £1,000 to £3,000 per junction surveyed.
Who can prepare a Transport Assessment?
Transport Assessments must be prepared by qualified transport planning consultants with demonstrable expertise in traffic engineering and highway design. Most practitioners hold membership of the Chartered Institution of Highways and Transportation (CIHT) or are chartered through the Institution of Civil Engineers. Highway authorities will scrutinise the competence of the assessor and may reject assessments prepared by individuals lacking appropriate qualifications or experience.
How long does a Transport Assessment take?
The preparation of a Transport Assessment typically takes 6 to 12 weeks, though this can vary depending on the need for traffic surveys, the complexity of junction modelling, and the extent of liaison with the highway authority. Traffic surveys need to be conducted during neutral months (avoiding school holidays, bank holidays, and August) which can affect timing. Pre-application discussions with the highway authority to agree the scope of the TA should be factored in, as should review periods — highway authorities typically take 3 to 6 weeks to provide comments on a submitted TA.
Frequently Asked Questions
What is the difference between a Transport Assessment and a Transport Statement?
A Transport Assessment is a comprehensive document required for developments with significant transport implications, involving detailed traffic surveys, junction modelling, and trip generation analysis. A Transport Statement is a simpler, less detailed document for smaller developments whose transport impacts are less severe. The threshold between the two varies by highway authority but is typically around 50 dwellings for residential schemes.
What is TRICS and why is it used in Transport Assessments?
TRICS (Trip Rate Information Computer System) is the UK's national database of trip generation surveys. It contains data from thousands of survey sites across a range of land uses and is used to predict how many vehicle and person trips a proposed development will generate. Highway authorities expect trip generation to be evidenced using TRICS data, and the parameters used to interrogate the database should be agreed with the highway authority during scoping discussions.
Do I need new traffic surveys for a Transport Assessment?
In most cases, yes. Highway authorities expect traffic surveys to reflect current conditions and are generally no more than three years old. Surveys should be conducted during neutral months and on neutral days — typically Tuesday to Thursday during school term time, avoiding August and public holidays. Common survey types include Automatic Traffic Counts, Manual Classified Counts at junctions, and queue length surveys.
What junction modelling software is used?
The most commonly used junction modelling software in the UK includes ARCADY for roundabouts, PICADY for priority junctions, and LinSig for signalised junctions. For more complex assessments involving multiple junctions or network-wide impacts, microsimulation software such as VISSIM, Paramics, or AIMSUN may be required. The choice of software should be agreed with the highway authority during scoping.
Can a Transport Assessment result in my application being refused?
Yes. Paragraph 115 of the NPPF states that development should only be refused on highway grounds if the residual cumulative impacts on the road network would be severe, or if there would be an unacceptable impact on highway safety. If the Transport Assessment demonstrates that impacts can be mitigated to acceptable levels through highway improvements, travel plan measures, or financial contributions, the application should not be refused on transport grounds alone.
What mitigation measures are typically proposed in a Transport Assessment?
Common mitigation measures include junction improvements such as new roundabouts or signal upgrades, new pedestrian and cycle infrastructure, bus stop improvements and public transport contributions, implementation of a Travel Plan to promote sustainable travel, highway safety improvements, and financial contributions toward strategic transport schemes. The appropriate level of mitigation is negotiated with the highway authority.
Do I need to consider the impact on the strategic road network?
If your development is likely to generate significant traffic on the strategic road network — motorways and major A-roads managed by National Highways — then yes. National Highways is a statutory consultee for developments affecting the strategic network and will require the Transport Assessment to model impacts on relevant junctions and link roads. Their response can be a determining factor in whether planning permission is granted.
How are parking standards applied in a Transport Assessment?
Parking provision should be assessed against the local authority's adopted parking standards, which set out maximum or minimum spaces per dwelling, per square metre of floorspace, or per employee depending on the land use. The TA should justify the proposed parking provision and demonstrate that it will not result in overspill parking on surrounding streets. In sustainable locations with good public transport, reduced parking provision may be acceptable.
What role does the highway authority play in the TA process?
The highway authority — usually the county council or unitary authority — is a statutory consultee on planning applications with transport implications. They review the Transport Assessment and advise the planning authority on whether the development is acceptable in highway terms. Their input influences the scope of the TA, the methodology used, and the mitigation measures required. Early engagement with the highway authority is strongly recommended.
Can I submit a planning application before the Transport Assessment is complete?
The planning application will not be validated without a Transport Assessment if one is required by the local authority's validation checklist. Submitting an incomplete or draft TA is possible in some circumstances, but the highway authority is unlikely to provide formal comments until the full assessment is available. This approach risks significant delays and is generally not recommended.