What is a Transport Assessment?
A Transport Assessment is a technical report that examines the likely transport impacts of a proposed development. It looks at how people will travel to and from the site, what effect that movement will have on the surrounding road network and public transport infrastructure, and what measures are needed to manage or reduce that impact.
Transport Assessments are a standard requirement for planning applications involving significant development. They are prepared by chartered transport planners and submitted alongside the planning application to satisfy the requirements of the local planning authority and, where relevant, Transport for London.
What is the Difference Between a Transport Assessment and a Transport Statement?
These two documents are often confused, but they serve different purposes depending on the scale of a scheme.
A Transport Statement is a lighter document used for smaller developments where transport impacts are expected to be modest. It sets out the likely trip generation and travel characteristics of the proposal without the detailed modelling that a full Transport Assessment requires.
A Transport Assessment is required for larger or more complex schemes where the development is likely to generate significant vehicle movements or where the site is located on a sensitive part of the highway network. It involves a fuller analysis of trip generation, traffic distribution, junction capacity and sustainable transport provision.
We advise on the appropriate level of assessment before any work begins, so you are not paying for a document that is more detailed than your application requires.
When is a Transport Assessment Required?
National planning practice guidance sets out that a Transport Assessment or Transport Statement should accompany planning applications where the proposed development has the potential to generate significant amounts of movement. In practice, the thresholds vary between local planning authorities, and boroughs publish their own guidance on when these documents are required.
In London, Transport for London acts as a statutory consultee for applications that exceed the Mayor of London's referable thresholds. For these schemes, the Transport Assessment must address TfL's Healthy Streets approach, cycle infrastructure requirements, and the Mayor's Transport Strategy. Getting this right from the outset avoids costly delays and pre-application objections from TfL.
Change of use applications can also trigger the requirement for transport documents, particularly where a proposed use is likely to generate materially different travel patterns to the existing use — for example, a change from office to residential, or from retail to a medical or educational use.
If you are not sure whether your application needs a Transport Assessment or a Transport Statement, we can advise quickly and without charge.
Our Transport Planning Services
We provide the full range of transport planning documents required to support planning applications across London and the wider UK. Our chartered transport planners work on schemes of all sizes, from single-unit residential developments to large mixed-use applications.
Transport Assessments
A full Transport Assessment covering trip generation, traffic distribution, junction capacity analysis, sustainable travel provision and accident record review. We work to the scope agreed with the local planning authority and TfL where applicable.
Transport Statements
A proportionate document suitable for smaller schemes where a full Transport Assessment is not required. We confirm the appropriate level of assessment with the local authority before starting work.
Travel Plans and Sustainable Travel Statements
A Travel Plan sets out the measures that will be put in place to encourage occupants of a development to travel by sustainable modes. These are required for many larger applications and are often secured by planning condition or s106 obligation. We prepare Travel Plans for residential, commercial, educational and mixed-use developments.
Delivery and Servicing Management Plans
Required for commercial developments and increasingly requested for larger residential schemes, these documents set out how deliveries and servicing vehicles will access and leave the site without causing harm to the surrounding road network.
Car Park Management Plans
These documents manage access to, and use of, on-site parking to ensure it operates safely and efficiently. They are often required as part of a planning condition on commercial or mixed-use developments.
Parking Surveys
Where a development relies on shared or on-street parking, or where a reduced parking provision needs to be justified, a parking survey establishes the existing level of parking stress in the area. We coordinate overnight and daytime surveys to the standard required by the local authority.
Traffic Surveys
We manage the collection of existing traffic flow data on the local highway network, which forms the baseline for junction capacity modelling and traffic impact assessment.
Construction Management Plans and Construction Logistics Plans
These documents set out how construction activity will be managed to minimise the impact on the surrounding road network, including delivery routing, site access, worker travel and dust and noise management. They are required for many London applications and are often secured by pre-commencement condition.
How We Approach a Transport Assessment
Establishing the Scope
Before drafting begins, we agree the scope of the assessment with the local planning authority and, where relevant, TfL. This confirms the assessment area, the survey requirements, the modelling approach and the assessment years. Getting the scope agreed upfront avoids abortive work and reduces the risk of objections on technical grounds later in the process.
Trip Generation
We calculate the number of person trips and vehicle movements the development is likely to generate using the TRICS database, which is the nationally accepted tool for trip rate calculation. Where a TRICS-derived rate is not appropriate — for example, where the development type is unusual or where a more site-specific estimate is needed — we use bespoke survey data from comparable sites.
Trip Distribution and Assignment
Once trip generation has been established, we predict how those trips will be distributed across the surrounding network using gravity modelling, empirical travel pattern data, or a combination of both. We also account for trips generated by the existing use of the site, which are netted off to produce a realistic picture of the net impact on the network.
Junction and Network Capacity Assessment
We assess whether the local highway network can accommodate the predicted level of additional traffic during the agreed assessment periods, typically the weekday AM and PM peaks and the weekend peak. Where junction modelling is required, this uses industry-standard software to test existing, opening year and future design year scenarios, with traffic growth applied using NTEM forecasts or locally agreed growth rates.
Sustainable Travel
In line with Chapter 9 of the NPPF 2024 and the Mayor's Transport Strategy, sustainable travel options are assessed and promoted throughout the process. Improvements to walking and cycling infrastructure, public transport access and Travel Plan measures are considered before any highway capacity improvements are proposed.
Accident Record Review
We review the personal injury accident record for the local highway network to identify any existing safety issues that need to be addressed as part of the development. This forms a standard part of a Transport Assessment and is used to demonstrate that the development will not worsen existing highway safety conditions.
Conclusions and Recommendations
The assessment concludes with a clear summary of findings, demonstrating how the development complies with the NPPF 2024, the London Plan where applicable, and the policies of the relevant Local Plan.
Transport Assessments in London - What You Need to Know
London applications present particular challenges that do not apply in the same way elsewhere. TfL's involvement as a statutory consultee means that the Healthy Streets approach and the Mayor's Transport Strategy carry significant weight alongside borough planning policy. Failure to address TfL's requirements early can result in holding objections that delay determination by months.
We regularly prepare Transport Assessments and Travel Plans for applications across all London boroughs, including those involving the Strategic Road Network and Red Routes where TfL takes a particularly close interest. We understand the borough-level differences in parking standards, cycle infrastructure requirements and servicing arrangements, and we factor these into every assessment from the outset.
Frequently Asked Questions
Do I need a Transport Assessment for a change of use application?
It depends on the nature of the change and the likely difference in trip generation between the existing and proposed uses. A change from a low-footfall office use to a busy medical centre or educational facility, for example, is likely to require at least a Transport Statement. We can advise you quickly on whether a document is needed and at what level.
How long does a Transport Assessment take to prepare?
A straightforward Transport Statement can typically be prepared within 2 to 3 weeks of receiving the necessary information. A full Transport Assessment involving traffic surveys and junction modelling will usually take 6 to 10 weeks, depending on survey availability and the complexity of the scheme. We will give you a realistic programme when we provide your fee proposal.
Do I need a parking survey?
A parking survey is usually required where a development proposes reduced parking provision and needs to demonstrate that existing on-street capacity is available to absorb any overspill. It is also required where a development relies partly on shared parking. Borough guidance varies on survey methodology, and we advise on the correct approach for your specific authority.
What is a Healthy Streets Assessment?
The Healthy Streets approach is TfL's framework for assessing the impact of development on the pedestrian and cycling environment. It uses 10 indicators to measure how walkable and cycle-friendly the area around a development is, and what improvements the development should contribute to. It is a standard element of Transport Assessments submitted for TfL-referable applications in London.
Can you help if a Transport Assessment has already been refused or objected to by TfL?
Yes. We regularly review and supplement Transport Assessments prepared by others where TfL or a local highway authority has raised technical objections. We identify the specific concerns and prepare the additional technical work needed to resolve them.
Get a Quote
We provide Transport Assessments, Transport Statements, Travel Plans and Parking Surveys for planning applications across London and the UK. We will confirm the appropriate level of assessment for your scheme before any work begins, so you have a clear picture of what is needed and what it will cost.
Call us on 02031500183 or email enquiries@4dplanning.com to speak to a chartered transport planner.
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