Transport planners: database access and signed outputs

When a highway officer disputes a transport submission, the argument is usually about trip rates, and the trip rates almost always come out of one database. A transport planner with TRICS access can show where every number came from, which surveyed sites were selected, and why. Without that licence, the figures in a transport assessment are either borrowed second hand or estimated, and a sceptical officer has no way to check them.

That is the practical reason competence matters in this field. The regulations do not reserve transport evidence to a protected profession in the way that ecology licensing or fire engineering is reserved. The constraint is commercial and evidential: database access, membership that signals a tested skill set, and a named author who will stand behind the output at appeal.

Why database access matters to the evidence

TRICS is a subscription database of multi-modal trip rate surveys carried out at real sites across the United Kingdom and Ireland, maintained for the consultancies, developers and local authorities that licence it. Trip generation evidence in a planning submission is normally derived from it, and the highway authority will often hold its own subscription, which means the officer can rerun your selection.

Two consequences follow. First, the output has to be reproducible. A table of trips with no record of the surveyed sites behind it cannot be tested, and an officer who cannot test it will substitute their own run. Second, the selection itself becomes the argument. Most trip rate disputes are not about arithmetic but about which surveyed sites were considered comparable.

Where a consultant does not hold a licence, ask how trip generation will be evidenced. Sometimes the honest answer is a first principles assessment or observed counts at a comparable local site, and for a small change of use that can be enough. For anything that triggers a full assessment, it rarely is.

Membership and chartered routes in the field

There is no single qualification. The combinations you will see on a competent transport planning submission are:

• Chartered membership of the Chartered Institution of Highways and Transportation, which covers highway design and transport planning.
• The Transport Planning Professional qualification, a tested assessment of transport planning competence rather than a membership grade.
• Chartered membership of the Chartered Institute of Logistics and Transport, more common where freight, servicing and travel planning dominate.
• Chartered engineer status through the engineering institutions, usual where junction design, geometry and structures are involved.

None of these is a licence to practise, and none guarantees a good report. What they tell you is that someone has had their work assessed by peers. For a scheme where access geometry or capacity is contested, that matters more than the length of the firm's client list. The same reasoning applies to checking a consultant's appeal track record before you appoint.

Site selection within a trip rate database

This is the technical heart of the appointment, and it is worth understanding even if you are commissioning rather than doing the work. A trip rate run is defined by a set of filters, and each one is a judgement that can be challenged:

1. Land use category and sub-category, which has to match the proposed use rather than approximate it.
2. Region and area type, because trip rates differ between an inner London site and a market town.
3. Location type, such as town centre, edge of town centre, suburban area or free standing site.
4. Parking provision at the surveyed sites, which drives car driver rates more than almost anything else.
5. Survey date range, since older surveys predate changes in travel behaviour and online retail.
6. Days and hours surveyed, matched to the assessment periods agreed with the authority.
7. Site size range, so that the selected surveys bracket the proposal rather than sitting far above or below it.

The output should list every selected site with its reference, location, size and survey date, and the report should explain the exclusions. Where a filter produces only two or three sites, say so rather than presenting a mean as though it rested on a wide sample. The database publisher issues guidance on reasonable use of the system, and following it is the difference between a run that survives scrutiny and one that does not.

Who checks the output and how

Three sets of eyes should land on a trip generation table before it goes out.

The author, who should reconcile the trip rates against observed conditions. If the database says a site generates forty arrivals in the morning peak and the existing comparable premises down the road plainly do not, something in the selection is wrong.

A second consultant within the practice, because the commonest errors are mechanical: the wrong sub-category, trip rates applied to the wrong unit of measurement, or gross floorspace used where the database expects net.

The highway authority, at scoping stage. Agreeing the land use category, the assessment years, the peak periods and the filter set before the work is done removes the most expensive form of rework. Where the strategic road network is affected, the national highways body will want the same agreement.

Highway authority expectations on authorship

Local highway authorities rarely publish a list of accepted consultants, and you should be sceptical of any claim that such a list exists. What they do expect is a named author, stated competence, and a report that identifies its assumptions clearly enough to be audited.

For a transport assessment on a major scheme, expect the authority to want the trip rate output appended in full, the junction modelling files available on request, and the survey data that underpins any calibration. For a smaller transport statement, a shorter document with the same traceability is usually accepted.

One honest uncertainty: practice varies considerably between authorities on how much raw material they ask for, and a scheme that sailed through in one district may be sent back for appendices in the next. Ask the officer at scoping what they want appended.

Junction modelling competence as a separate skill

Trip generation and junction capacity modelling are different jobs, and the second is more specialised. Deterministic capacity assessment of a priority junction or roundabout is routine. Signal optimisation, linked signal networks and microsimulation are not, and a model that has not been calibrated and validated against observed queues and journey times will be picked apart.

If the scheme turns on junction capacity, ask directly who will build the model, what software family they will use, what observed data the calibration rests on, and whether the authority has a preferred approach. Authorities that maintain their own strategic models sometimes require a scheme to be tested in them, which changes the appointment entirely.

Scoping the appointment with the authority

A transport appointment that starts with a scoping note rather than a fee proposal usually costs less overall. The note should record the proposed use and quantum, the assessment years and peak periods, the trip rate source and proposed filters, the junctions to be assessed and the method for each, the survey work required, the parking standards applied and the travel plan expectation.

Send it to the highway authority with the pre-application request. Written agreement on those points is worth more than any amount of care taken afterwards, because it removes the argument that the evidence base was scoped wrongly. It also protects you if circumstances change and you need to consider changing consultant mid-application, since the scope sits in a document rather than in one person's head.

If you need a reviewer to check or sign off transport work, the professional directory is the route for requesting review of an AI-assisted draft. 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, and this article is general guidance rather than legal advice.