The access and visibility section of a Transport Statement

The access and visibility section of a Transport Statement has one job: to show the highway authority that a vehicle can enter and leave the site safely at the speeds traffic actually travels on the road outside. That means a visibility splay drawn to an X distance measured back from the give way line and a Y distance measured along the carriageway, both justified by measured approach speeds rather than by the posted limit. Get the speed survey wrong and everything downstream in the section fails with it.

For a small scheme, a handful of dwellings or a change of use, this is usually the only part of the Transport Statement a highway engineer reads closely.

What the section has to prove

Four things, in this order. That the access geometry suits the vehicles that will use it. That drivers emerging can see far enough in both directions. That drivers on the main road can see the access in time to react. And that construction and servicing vehicles can get in, turn and leave without reversing onto the highway.

Everything else in the section is supporting material for those four propositions. A statement that lists standards without demonstrating compliance on a drawing will come back with a holding objection, and a holding objection on a minor application usually costs the eight week determination period.

The threshold between a Transport Statement and a full Transport Assessment is set by the scale of trip generation, not by the complexity of the access. A single access serving five houses onto a 40 mph rural road can need more access work than a fifty unit scheme onto an estate road.

Measuring approach speeds rather than assuming them

Manual for Streets is explicit that visibility should be based on observed vehicle speeds, not on the speed limit. On a 30 mph road with a long straight approach the recorded 85th percentile wet weather speed is often 34 to 36 mph, which lengthens the splay you need. On a narrow lane signed at 60 mph it is frequently under 30, which shortens it.

A defensible speed survey has a few features. Automatic counters or radar rather than a person with a speed gun. A location that reflects the approach to the access, set back from junctions, crests and traffic calming. Seven consecutive days including a weekend. Separate figures for each direction. The 85th percentile reported, with the mean alongside it.

Surveys taken in school holidays or during roadworks on a parallel route are worth repeating. So are surveys where the counter sat inside a queue, because a queue records speeds that will not exist once the queue clears.

X and Y distances and where the figures come from

The X distance is measured from the give way line back along the centre line of the access. Manual for Streets normally uses 2.4 metres, which puts the driver's eye far enough forward to see past a boundary wall while keeping the bonnet clear of the carriageway. A reduced 2.0 metres is sometimes accepted on very lightly trafficked, low speed streets, and 4.5 metres appears in some authorities' standards for accesses onto classified roads.

The Y distance is the stopping sight distance for the measured approach speed, set out along the nearside edge of carriageway in each direction. The figures most often applied to minor accesses are these.

Check the current edition of Manual for Streets and the local highway authority's own design guide before fixing these, because authorities vary in how they interpolate between values and some still apply Design Manual for Roads and Bridges distances on higher speed roads. Accesses onto the strategic road network are a separate regime entirely and National Highways will be consulted.

Two details decide whether the splay drawing survives scrutiny. Eye height is taken at 1.05 metres above the access surface, and the object height at the far end is 0.6 metres, so a 900 millimetre brick wall inside the splay blocks it and a 400 millimetre kerbside verge does not. And the splay must be shown as a clear area on plan, hatched, with the 0.6 metre maximum height of anything within it noted on the drawing rather than left to a condition.

Gradients, widths and turning inside the site

Most authorities want the first stretch of the access at or close to level, commonly 1 in 20 over the first five metres, so that a stationary vehicle sits flat while the driver looks and so that surface water drains back into the site rather than across the footway. Beyond that, 1 in 10 is a usual maximum for a private drive.

Width depends on what it serves. A single dwelling access at 3.0 to 3.7 metres is normally accepted. A shared drive serving several dwellings needs either a width that lets two cars pass or formal passing places at intervals, and once refuse and fire access are in play the constraint becomes the vehicle, not the car.

Turning within the site matters where the access meets a classified road or where the splay is tight. The test the officer applies is simple: can a car leave the site in forward gear. Show the turning area on plan with the swept path drawn on it, not as an empty rectangle labelled "turning head".

Vehicle tracking and the drawings a highway engineer expects

Swept path analysis, produced from the actual design vehicle rather than a generic car, is what converts a layout from plausible to demonstrated. For housing that usually means three runs: a private car, a refuse freighter of about 11.2 metres, and a fire appliance.

Fire service access is governed by Approved Document B rather than by highway standards, and the two sets of numbers differ. Approved Document B works on a hose laying distance from the appliance parking position to all points inside the dwelling, which on a long private drive is often the binding constraint even where the highway authority is content.

The drawing set that clears a minor access is short.

1. A site access plan at 1:200 with both splays hatched and dimensioned, including the X and Y values used.
2. A long section through the access showing gradients over the first ten metres.
3. Swept path drawings for each design vehicle, overlaid on the proposed layout.
4. A speed survey appendix with the raw data, the survey location marked on a plan and the dates.
5. Where construction access differs from the permanent access, a separate drawing, which is also the point at which a Construction Traffic Management Plan starts to be useful.

Splays over land you do not control

A splay that crosses a neighbour's front garden is not a splay. It is an aspiration.

Where part of the visibility area falls outside the application site and outside the publicly maintainable highway, say so plainly, identify the ownership, and serve the correct notice with the ownership certificate. A Grampian style condition can sometimes bridge the gap, but only where there is a reasonable prospect of the works being carried out, and a neighbour who has refused in writing removes that prospect.

Where the splay sits within highway land, confirm the extent from the highway authority's records rather than from the kerb line, because verges and service strips are frequently highway even when they look private. Hedges and walls inside highway land can usually be cut back under the authority's powers, which is a different and easier conversation than one with a neighbour.

Physical works to form the crossing need consent in their own right: section 184 of the Highways Act 1980 for a vehicle crossing over a footway, and section 278 where the access alters the highway itself. Neither is granted by planning permission, and both have their own timescales and bonds.

The objections that come back most often

Speed surveys that use the speed limit instead of observed speeds. Splays drawn to the boundary rather than to the edge of carriageway. Retained boundary walls inside the splay with no note on the height. Turning areas that a refuse vehicle cannot use. Gradients measured from a levels survey that stops at the site boundary. And accesses onto a bus route or within the tapers of a junction, where the authority's starting position is refusal whatever the geometry shows.

Most of these are avoidable in a morning's work before the drawings are issued. The one that is not avoidable by drawing is the splay over third party land, and it is better to find that out at the feasibility stage than in an officer's report.

This is general guidance, not legal advice. Highway standards vary between authorities, so confirm the applicable design guide and splay requirements with the local highway authority before relying on any figure here.

PlanScope can draft the access and visibility narrative from your site data and survey figures, and you can browse all 66 report types to see what else a minor application needs. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.