The sustainable transport section of a Transport Assessment
Trip generation is arithmetic, accessibility is judgement. Isochrones instead of circles, LTN 1/20 route quality, honest bus evidence and measures that can actually be secured.
The sustainable transport section of a Transport Assessment has one job: to show that people can reasonably reach the site on foot, by cycle and by public transport, and that the scheme does something to make those choices easier. It is the part of the assessment highway authorities read hardest, because trip generation is arithmetic while accessibility is judgement, and judgement is where an officer can disagree with you.
Get it wrong and the objection is predictable. The site is in an unsustainable location, the walking distances are measured in straight lines, the cycle route is a painted strip on a 40 mph road, and the travel plan promises a notice board.
What the section has to demonstrate
National guidance on travel plans, transport assessments and statements asks for assessments that are proportionate to the scale of the development and its likely impact. For the sustainable transport element that means three findings, evidenced rather than asserted.
Where the everyday destinations are and how far they are by the actual route people would walk or cycle: school, shop, GP, employment, station, bus stop.
Whether those routes are usable by the people who will make the trips, which covers crossings, footway width, lighting, gradient, severance by a main road, and whether a parent with a buggy or a wheelchair user can complete the journey.
What the development provides or contributes that changes the position, with each item capable of being secured.
The third finding is the one that converts a descriptive section into a persuasive one. An assessment that catalogues the existing situation and stops has not made a case.
Accessibility audit and catchment plans
The audit is a site visit, not a desk exercise. Walk the routes. Photograph the pinch points. Note the dropped kerb that is not there, the crossing with no tactile paving, the footway that disappears for 40 metres outside the garage.
Catchment plans should be drawn as isochrones along the network rather than as circles on a map. A 400 metre circle around a bus stop and a 400 metre walking isochrone look very different where a railway line or a dual carriageway sits between the two. Highway authorities now routinely reject circles, and rightly.
Common reference distances used in practice come from Manual for Streets, which describes walkable neighbourhoods as typically having a range of facilities within about 800 metres, roughly ten minutes on foot. Treat that as a reference point and not a threshold. The quality of the route matters more than the number, and saying so with photographs is stronger than quoting a figure.
| Element | Weak version | What stands up |
|---|---|---|
| Walking catchment | 800 m radius circle | Isochrone along the footway network |
| Route quality | "Footways are present" | Width, lighting, crossings, gradient, photographs |
| Bus accessibility | Timetable frequency | Daytime, evening and weekend frequency and journey time to key destinations |
| Cycle route | "On-road route available" | Assessment against LTN 1/20 design principles |
| Measures | "A travel plan will be prepared" | Named measures, trigger points, funding, monitoring |
Cycle route quality rather than distance
Cycle Infrastructure Design, LTN 1/20, changed what an assessment has to say about cycling. Its core design principles ask whether a route is coherent, direct, safe, comfortable and attractive, and it sets out where separation from traffic is needed based on speed and volume.
Applied honestly, that means a shared carriageway on a 40 mph road carrying significant traffic cannot be presented as a cycle route for a family. Say so, then say what the development does about it. A contribution towards a crossing, a short length of segregated path to link to an existing route, or a change to the site access to remove a conflict are the sorts of measures that satisfy an objection.
Active Travel England is a statutory consultee on larger applications, with thresholds set around 150 or more dwellings, larger commercial floorspace or site area. Where it is consulted, the walking and cycling content gets specialist scrutiny, so build the section to withstand it rather than adding active travel material at the end.
Cycle parking quantum comes from the local plan or a parking standards supplementary planning document, and in London from the London Plan. Give the calculation: standard applied, units or floorspace, resulting number, split between long stay and short stay, and the type of stand. Covered, secure, accessible long stay parking at ground level is what gets approved; a Sheffield stand in the open at the back of a bin store does not.
Bus services and the evidence for them
Quoting a weekday daytime frequency is the most common weakness in this section. The useful evidence is the full service picture: frequency by time of day, first and last service, Saturday and Sunday provision, and journey time to the destinations that matter for the development's trips.
If the service does not support the development's travel patterns, say so and address it. A shift pattern at a distribution unit that starts at 6am is not served by a bus that starts at 7.30am, and an assessment that implies otherwise loses credibility on everything else.
Where a contribution towards a service is proposed, it needs to be deliverable: the operator's position, the sum, the duration and the mechanism. Open ended contributions towards bus service enhancement without an operator conversation behind them are rarely accepted now.
Securing the measures
Everything the section relies on has to be capable of delivery through a condition or a planning obligation. Three mechanisms cover most of it.
- Conditions for physical works on or adjoining the site, with a trigger such as before first occupation.
- A section 106 obligation for financial contributions, off-site works that need a highway agreement, and the travel plan itself where monitoring is required.
- A section 278 agreement with the highway authority for works in the public highway, which runs on its own timetable and should be started early.
The travel plan sits alongside this rather than inside it. The assessment identifies what is needed. The travel plan sets the targets, the measures, the monitoring regime and the remedial actions if targets are missed. Keeping them separate but consistent is the point, and inconsistency between the two is a frequent consultee criticism.
Where consultees push back
Four objections come up repeatedly.
Straight line distances. Fixed by isochrones along the network.
Desk-based route assessment. Fixed by a site visit with photographs and a route by route commentary.
Measures that are aspirations. Fixed by naming the measure, its cost, its trigger and the mechanism.
Numbers that disagree with other documents. The trip rates in the assessment, the parking numbers on the layout drawing, the cycle store on the architect's plan and the travel plan targets all have to tell the same story. Where servicing is also in play, the servicing and deliveries content of a transport statement uses the same discipline.
A Transport Assessment is a report councils expect a suitably qualified transport planner to author, and professional review is strongly advised before submission. PlanScope can draft the structure and the policy framing with flags where site survey data is missing, which saves the drafting time rather than the survey work.
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. Browse the full set of report types to scope a major application.
Frequently asked questions
How should walking catchments be drawn?
As isochrones along the footway network, not as circles on a map. A radius ignores railway lines, rivers and dual carriageways, so it overstates accessibility wherever severance exists. Highway authorities routinely reject circle based catchments, and an isochrone with a route commentary and photographs is the version that survives scrutiny.
What does LTN 1/20 require of a Transport Assessment?
Cycle Infrastructure Design sets out core design principles asking whether a route is coherent, direct, safe, comfortable and attractive, and indicates where separation from traffic is needed based on speed and volume. An assessment should test existing and proposed cycle routes against those principles rather than noting that a road exists.
When is Active Travel England consulted?
It is a statutory consultee on larger applications, with thresholds set around 150 or more dwellings, larger commercial floorspace or a larger site area. Check the current threshold figures before assuming your scheme falls outside. Where it is consulted, the walking and cycling content receives specialist review rather than a general highways comment.
What evidence is needed for bus accessibility?
Frequency by time of day, first and last service, Saturday and Sunday provision, and journey time to the destinations the development's trips will actually use. A weekday daytime frequency alone is the most common weakness. Where a service contribution is proposed, the operator's position, the sum, the duration and the mechanism all need stating.
How are sustainable transport measures secured?
Physical works on or adjoining the site go in conditions with a trigger such as before first occupation. Financial contributions, off-site works and travel plan monitoring go in a section 106 obligation. Works in the public highway need a section 278 agreement with the highway authority, which runs on its own timetable.
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.