Transport planner competence and the trip rate database

No statute says who may write a Transport Assessment. What decides the question in practice is whether the author's organisation holds a subscription to the national trip rate database, because a highway authority that expects trip rates derived from it will not accept rates that came from somewhere else without an explanation. Competence and data access are separate things, and a developer needs to check both before appointing.

What highway authorities expect of a transport author

Local validation lists commonly ask for a transport assessment or statement prepared by a suitably qualified transport consultant, without defining the phrase. National guidance on transport evidence describes the process and the content rather than the author.

So the expectation is built from practice. A highways development management officer reading an assessment is looking for someone who has agreed a scope with an authority before, who knows what the local standards documents say, who can produce junction modelling that runs, and who will answer a technical query without escalating it. That is a description of experience rather than of a qualification.

Councils usually expect a suitably qualified author for a Transport Assessment, and professional review of any draft is strongly advised before submission. An AI-assisted draft can carry the policy framing, the site description and the report structure, and it flags where survey data is missing rather than inventing a figure.

Institute routes and chartered status

Several routes exist and they signal different competences.

The Transport Planning Professional qualification, developed jointly by the Chartered Institution of Highways and Transportation and the Transport Planning Society, assesses transport planning practice specifically, including evidence, appraisal and delivery. It is the closest thing the field has to a competence standard aimed at this work.

Chartered engineer status through the Institution of Civil Engineers or the Chartered Institution of Highways and Transportation signals engineering competence, which matters for junction design, geometry and highway works under a section 278 agreement. Membership of the Chartered Institute of Logistics and Transport is more often relevant to freight, servicing and delivery planning.

None of these is required by law. All of them are useful evidence when you are comparing two quotations, and the more useful question is which named individual will do the work rather than which letters appear on the firm's website.

Database access and why it matters

The national trip rate database is a subscription service. Member organisations pay for access, and the database is not available to non-subscribers, which means a consultant without a subscription cannot derive trip rates from it.

That matters because most highway authorities expect trip generation to be derived from the database, filtered to comparable sites, with the filtering shown. The alternatives are site-specific surveys of a comparable development, which cost money and take time, or census-based journey to work data, which is useful for modal split but not for peak-hour trip generation.

Ask three questions. Does your organisation hold a current subscription. Will the filtering criteria and the resulting survey set be shown in an appendix. And will you agree those criteria with the highway authority before running the analysis. A consultant who answers yes to all three is offering a process the authority can check, which is most of what an officer wants.

Modelling competence against report writing

Two different skills, and a firm can have one without the other.

Capacity modelling of priority junctions, roundabouts and signal-controlled junctions uses established software packages, and running them is not difficult. Interpreting them is. The judgement sits in choosing the assessment years, deciding which committed developments to include in the baseline, setting the flare lengths and saturation flows realistically, and recognising when a ratio of flow to capacity just under the accepted threshold is an artefact of an optimistic input rather than a real result.

Report writing is a separate skill again. A transport assessment has to explain a technical argument to a planning officer and a committee, both of whom will read the summary and the conclusions and little else.

Ask to see two previous assessments the individual wrote, ideally one that attracted a highway objection and was resolved. How a consultant handles disagreement with an officer tells you more than a clean example does.

Checking a trip rate selection yourself

You do not need to be a transport planner to sanity-check trip rates. Four checks catch most problems.

Look at how many surveys are in the selected set. A rate derived from three surveys is far weaker than one derived from thirty, and the range between the highest and lowest survey tells you how much confidence the average deserves.

Check the geographic filter. Including or excluding Greater London changes residential and retail rates noticeably, and the decision has to match the site. Check the size bands, because a rate drawn from developments much larger or smaller than the proposal is not comparable. And check the unit the rate is expressed in, whether per dwelling, per 100 square metres of gross floor area, or per bed space, and make sure the arithmetic that follows uses the same unit.

Then look for the honest bit. A good assessment will say where the selection is uncertain and will test a sensitivity case. One that presents a single number with no range is telling you less than it appears to.

Why a highways officer rejects an assessment

The reasons repeat across authorities.

No scoping agreement, so the assessment years, peak periods, junctions and trip rates were chosen unilaterally. Committed development omitted from the baseline, which understates future flows. Personal injury collision data not obtained for the standard period, or obtained and not analysed. Visibility splays drawn to a standard that does not match the recorded speed of the road. Sustainable transport dealt with as a paragraph of assertion rather than an assessment of walking and cycling routes against the relevant design guidance. And construction traffic left to a condition on a site where the access is difficult.

For major residential schemes above the relevant threshold, Active Travel England is a statutory consultee and assesses active travel provision on its own terms, which is a separate review from the highway authority's.

Scoping the appointment before work starts

Get the scope agreed in writing with the highway authority before the consultant starts modelling. It is the single change that most reduces cost and delay.

1. Confirm whether a transport statement or a full assessment is required, and whether a travel plan is expected.
2. Agree the assessment years, including the opening year and a future year.
3. Agree the peak periods and the network of junctions to be assessed.
4. Agree the trip rate methodology, filtering criteria and any survey requirement.
5. Agree the committed development list to be included in the baseline.
6. Agree the design standards for access geometry and visibility.
7. Record the agreement and attach it to the assessment as an appendix.

Where a scheme is small enough for a Transport Statement, the same scoping discipline applies at lower cost. The equivalent competence question for air quality authorship is covered in the note on air quality assessment authors and IAQM competence, and reviewers who can check a draft before submission are listed in the professional directory.

This is general guidance, not legal advice. Check the position with your local planning 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.