Who can prepare a Transport Assessment
Nothing in law says who may write a Transport Assessment. Highway authorities decide whether to believe it, and their confidence rests on institute membership, data access and modelling capability.
There is no statutory transport assessment author qualifications list. Anyone can write one. What decides whether the document survives is whether the local highway authority believes the trip generation, the junction capacity work and the accident analysis, and that judgement rests on three things: recognised professional standing, access to the trip rate data the authority itself uses, and the ability to model the junctions the authority cares about.
That gap between what the law requires and what the authority will accept catches developers out. A cheaper author is not a saving if the highways response is a holding objection asking for the whole assessment to be redone.
What the highway authority is assessing
The local highway authority is a statutory consultee on applications affecting the public highway, and its officer is looking for a small number of answers.
How many vehicle, pedestrian, cycle and public transport trips will the development generate, at what times, and where will they go. What happens to the junctions on the route when those trips are added to a future baseline that already includes committed development and background growth. Whether the access geometry, visibility splays and internal layout are safe and serviceable. Whether the personal injury collision record on the affected network shows a pattern the proposal would make worse.
Every one of those answers depends on method. An officer who cannot see the method cannot agree the conclusion, and the default response to an assessment they cannot check is an objection.
A Transport Assessment is the fuller document, used where the trip generation is material. A Transport Statement is the lighter version for smaller schemes. Councils usually expect a suitably qualified author for either, and professional review is strongly advised before submission.
Institute membership and chartered status
The two bodies that matter in practice are the Chartered Institution of Highways and Transportation and the Chartered Institute of Logistics and Transport. Membership of either, at chartered grade, tells an authority that the author has been assessed by peers against a competence framework and is subject to a code of conduct.
Many transport planners are also chartered engineers through the engineering institutions, which carries weight where the work involves highway design, drainage of the access or structures. That is a different competence from trip generation and modelling, and a practice that is strong on one is not automatically strong on the other.
What membership does not do is guarantee relevant experience. A chartered transport planner whose career has been in rail franchising is not the person to model a supermarket access. Ask for two or three assessments the individual has personally authored on schemes of similar type and scale in the last three years, and ask what the highway authority said about them. The wider question of what competent person means in planning legislation is worth understanding, because for transport there is no statutory definition at all.
Access to trip rate data and why it matters
Trip generation is where most assessments are attacked, and it is where the data question bites.
The industry standard source is the TRICS database, a subscription dataset of surveyed trip rates for different land uses, locations and site characteristics. Highway authorities subscribe to it. If your consultant does not, they cannot produce rates the officer can replicate, and they cannot interrogate the authority's own selection of comparison sites when the two of you disagree.
So ask directly whether the practice holds a current subscription, and ask to see the selection criteria behind the rates in the draft: which land use category, which region, which parking provision band, how many survey sites, which ones were excluded and why. A selection that produces a conveniently low rate from four sites in rural locations for an urban scheme will be picked apart.
Where TRICS has no suitable category, the alternative is a bespoke survey of a comparable operating site, agreed with the authority in advance. That costs money and takes time, and it is far better to discover the need at scoping than at consultation.
Modelling capability against desktop assessment
Capacity assessment is the second technical hurdle. Priority junctions, roundabouts and signalised junctions each need their own modelling approach, and authorities expect output they can audit: input files, flow diagrams, saturation flows, degree of saturation and queue lengths for each assessment year and peak period.
Some authorities also require microsimulation where a corridor rather than a single junction is affected, or where signals interact. That is a different skill set again, and it is expensive. Establish at scoping whether it will be asked for, because retrofitting a microsimulation model into a submitted application is close to starting over.
A desktop assessment with no junction modelling is appropriate for very small schemes where the trip generation is below the level at which capacity changes. Say so explicitly and show the arithmetic rather than leaving the absence of modelling unexplained.
Separating the assessment from the travel plan
These are different documents with different purposes, and conflating them weakens both.
The assessment describes and tests the impact. The Travel Plan is a management document with targets, measures, a named coordinator, monitoring surveys and remedies if targets are missed. Authorities increasingly secure travel plans by condition or obligation with monitoring fees attached, so the commitments in it become enforceable.
The practical risk is that a travel plan written to justify the assessment's mode share assumptions ends up promising reductions the development cannot deliver. If your assessment takes credit for a 10 per cent modal shift, someone will be surveying in three years to see whether it happened.
Independence where the client is the operator
There is no requirement for an independent author. The assessment is the applicant's evidence, and it is normal for it to be commissioned and paid for by the applicant.
What is not acceptable is an assessment that suppresses inconvenient results. Highway authorities read a great many of these and recognise the patterns: the peak hour chosen to avoid the school run, the collision search radius drawn to exclude a cluster, the assessment year set before a committed development opens, the sensitivity test that is missing.
A useful discipline is to ask your consultant, at draft stage, what the weakest point in the assessment is and what a hostile reviewer would say about it. If the answer is that there is no weak point, get a second opinion. Where an authority instructs its own consultant to review, that reviewer's fee is often recharged to the applicant, and a thin assessment turns into two rounds of review at your cost. Directories of reviewers, including the professional review route, exist partly for this reason.
Scoping the brief with the highway authority first
Everything above is cheaper to settle before anyone starts work. Scoping is a short document and a meeting, and it should fix:
- Whether a full assessment or a statement is required, and against which local threshold.
- The study area and the junctions to be assessed.
- The assessment years, including the opening year and any future year, and the growth factors to be applied.
- The peak periods and, where relevant, weekend or seasonal peaks.
- The trip rate source and the site selection criteria.
- The committed development to be included in the baseline.
- The collision data period and search area.
- Whether National Highways or the national active travel body needs to be engaged, which depends on proximity to the strategic road network and on scheme size.
Get the authority's agreement to that list in writing. A scoping note the officer has endorsed is the single most effective protection against a consultation response that rejects your method rather than your conclusions.
This is general guidance, not legal advice. Local thresholds and data requirements vary by authority, so check the position with your local highway authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval. For specialist technical reports, qualified professional input may be required.
Frequently asked questions
Is there a legal qualification needed to write a Transport Assessment?
No. Neither the planning legislation nor national guidance names a qualification or licence for transport assessment authors. Highway authorities apply their own judgement instead, and in practice they look for chartered membership of a recognised transport institution, relevant recent experience on similar schemes, and the ability to show a method they can check.
When is a Transport Assessment needed rather than a Transport Statement?
It depends on the scale of trip generation and on the local threshold. Authorities commonly set thresholds by unit numbers or floorspace, and PlanScope flags an assessment at around 50 or more dwellings or 2,500 square metres. National policy expects the level of detail to match the significance of the transport effects, so agree which document is required at scoping.
Does my consultant need access to the TRICS database?
In practice yes, for anything beyond the smallest scheme. TRICS is the trip rate dataset highway authorities use, and an assessment built on rates the officer cannot replicate is difficult to agree. Where no suitable TRICS category exists, the alternative is a bespoke survey of a comparable operating site, agreed with the authority in advance.
Can the same person write the assessment and the travel plan?
They often do, and there is no rule against it. Keep the documents separate, because the travel plan contains enforceable commitments with targets and monitoring while the assessment contains analysis. Problems arise when the travel plan is written backwards from the mode share the assessment needs, and the targets then cannot be met.
Who pays if the council instructs its own transport reviewer?
Many authorities recharge the cost of independent review to the applicant, either through a planning performance agreement or as a condition of accepting the assessment. A thin submission therefore costs twice: once to write and once to have reviewed and revised. Agreeing scope in writing before work starts is the cheapest way to avoid that.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.