What a Transport Assessment costs and why it varies
Two quotes for the same 60 unit scheme can differ by a multiple because nobody agreed a scope. Here is what actually sets a Transport Assessment fee, and how to get comparable prices.
A Transport Assessment can cost a few thousand pounds or well into five figures for the same number of units, and the transport assessment cost drivers are almost all decided before anyone writes a word. Scope, survey work and the number of junctions to be modelled set the fee. The report itself is a small part of it. Developers who get a surprising quote have usually asked for a price without an agreed scope, so the consultant has priced the worst case they can imagine.
Scoping controls the budget
The single largest variable is the study area and the list of junctions to be assessed, and that is agreed with the local highway authority rather than chosen by you.
A scoping note sent to the highway authority before commissioning the work should set out the proposed development quantum, the proposed trip rate source, the assessment years, the junctions to be modelled, the survey types and dates, and the accident data period. The authority's response either confirms it or adds to it. Either way you then have a defined brief that two consultants can quote against on the same basis.
Skipping that step is expensive twice over. You pay for work that may be rejected, then you pay again for the work the authority actually wanted.
Scoping also establishes whether you need a full Transport Assessment or whether a shorter Transport Statement will do, which changes the fee by a multiple rather than a margin.
Trip rate data and the database subscription
Trip generation is normally derived from a national trip rate database compiled from surveys of comparable sites. Access is by subscription, held by the consultancy rather than by you, so the cost reaches you indirectly through the fee.
Three things about trip rates affect the price. Selecting and defending a site sample takes professional time, because the output depends on the filters applied: land use category, location type, parking provision, survey year and site size. Where the proposed use has a thin sample in the database, the consultant may need to commission a bespoke survey of a comparable operating site, which is a separate cost. And where the authority disputes the sample, the time spent agreeing it is chargeable.
For common residential and employment uses on a site with decent comparables, this part of the work is routine. For an unusual use, it is not.
Traffic counts and the neutral month constraint
Survey work is the part of the budget that is most sensitive to timing, and it is the part that will delay a programme if it is left late.
Counts are expected in neutral periods, which in practice means avoiding school holidays, August and the weeks around Christmas, and avoiding anything abnormal such as roadworks on the approach. That leaves a limited number of usable weeks in the year. Missing them costs months, which is worse than the money.
The survey types that drive the cost are classified turning counts at each modelled junction over the peak periods, automatic traffic counts over a week for flow profiles and speeds, queue length surveys where a junction is already congested, and pedestrian and cycle counts where the scheme affects a crossing. A Parking Survey under the established overnight and weekend methodology is a separate commission again, and councils in parking stressed areas often want it.
Each junction added at scoping therefore adds a survey as well as a model.
Junction modelling and the software
Modelling costs scale with the number and type of junctions. A priority junction or a small roundabout is modelled with deterministic capacity software and is comparatively quick. Signalised junctions take longer, because signal timings have to be obtained, coded and validated. A microsimulation model of a corridor or a network is a different order of work again, and it is usually only required where the authority has an existing network model or where queues interact between junctions.
The other multiplier is the number of scenarios. A typical assessment runs a base year, a future year without the development, and a future year with it, in both morning and evening peaks. Add a committed development scenario, a mitigation scenario and a sensitivity test and the model runs multiply.
Where the site is on or near the strategic road network, National Highways becomes a statutory consultee and its own expectations on modelling and evidence apply, which tends to extend the work.
Accident data and the study area
Personal injury collision data for the surrounding network is obtained from the highway authority or from published road safety statistics, normally for a recent five year period, and analysed for clusters and for patterns that the development might worsen.
The cost here is proportional to the study area agreed at scoping. Analysing five years of records across one junction is a short task. Doing it across a corridor of a dozen junctions is not, and if the analysis finds a cluster, the authority may ask for a safety audit or a mitigation scheme that was not in the original brief.
Review fees charged by the authority
Several highway authorities charge for pre-application transport advice and for reviewing submitted transport evidence, often through a published schedule or a planning performance agreement. Those charges sit outside the consultant's fee and are easy to forget at budget stage.
Check the authority's published fee schedule rather than assuming, because the basis and the amount vary between authorities and are revised periodically. Where a planning performance agreement is in place, the transport officer's time is usually built into it.
Where a Transport Statement is enough
The cost difference between a statement and a full assessment is large enough to be worth testing properly.
PlanScope's detector flags a Transport Assessment at 50 or more dwellings or 2,500 m² or more of floorspace, and those are the thresholds it uses to prompt the report. National guidance and the authority's own validation list take precedence, and many authorities set lower local thresholds or ask for an assessment regardless of size where a site has a constrained access or sits in a congested area.
| Scheme characteristics | Usual evidence |
|---|---|
| Small scheme, unconstrained access, sustainable location | Transport Statement |
| Below the authority's threshold but with a difficult access | Transport Statement with junction capacity work |
| At or above the threshold, several junctions affected | Transport Assessment |
| Trip generation affecting the strategic road network | Transport Assessment with National Highways engagement |
A Travel Plan is normally required alongside either document for schemes above a local threshold, and it is a modest cost by comparison, though the monitoring commitments inside it carry a long tail.
Getting a comparable quote
Ask for the fee broken down into scoping and liaison, survey commissioning, trip generation, modelling by junction, accident analysis, reporting, and an allowance for responding to consultee comments. That last item is routinely omitted and routinely needed.
Also ask what is excluded. Mitigation design, a section 278 highway works design, a safety audit, additional scenarios requested by the authority and attendance at committee are often outside the base fee, and they are the items that turn a budget into an overrun.
An illustrative sequence for a 60 dwelling site helps. Scope agreed in October, counts commissioned for a neutral week in November, modelling through December, report in January, submission in February. Pull the scoping back to September and the same programme finishes a month earlier for the same fee. Leave it until June and you are either surveying in a school holiday the authority will not accept, or waiting until September.
Transport evidence is work councils expect from a suitably qualified transport planner, and professional review before submission is strongly advised. PlanScope can draft the narrative, the policy sections and the structure of the assessment from your project data at £50 per report, or on the Professional tier at £150 per month for unlimited reports, and the modelling and survey interpretation remain the consultant's. See PlanScope pricing.
PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.
Frequently asked questions
Why do Transport Assessment quotes vary so much?
Because the scope is usually undefined when the quote is given. The study area, the number and type of junctions modelled, the survey types and the number of assessment scenarios all set the fee. Agree a scoping note with the highway authority first, then ask two consultants to price the same defined brief.
When can traffic counts be carried out?
In neutral periods, which rules out school holidays, August and the weeks either side of Christmas, and anything abnormal such as roadworks on the approach. That leaves a limited number of usable weeks, so survey timing often sets the critical path on a planning programme rather than the fee.
Do highway authorities charge for reviewing transport evidence?
Several do, through a published pre-application or planning performance agreement schedule. The basis and the amount vary between authorities and are revised periodically, so check the authority's current published schedule rather than assuming. These charges sit outside the consultant's fee and are often missed at budget stage.
Is a Transport Statement cheaper than a Transport Assessment?
Substantially, because it involves less survey work, fewer modelled junctions and fewer scenarios. Whether it is acceptable depends on scheme size, the sensitivity of the access and the authority's local threshold. PlanScope flags a full assessment at 50 or more dwellings or 2,500 square metres or more of floorspace.
What is usually excluded from a Transport Assessment fee?
Mitigation design, section 278 highway works design, road safety audits, extra scenarios requested by the authority during determination, and attendance at committee. Responding to consultee comments is also often omitted even though it is almost always needed. Ask for exclusions in writing with the quote.
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.