Forming an access onto a classified road

A new access onto a classified road is judged on three things: whether a driver emerging can see far enough, whether a driver approaching can see the access in time, and whether the movements the access will generate are compatible with the road. Everything a highway authority asks for on a rural access application goes to one of those.

The classification of the road changes the standard applied, and on a trunk road it changes who applies it. That is the first thing to establish, before any drawing is produced.

Classification and why it changes the test

A, B and C roads are classified. Unclassified roads are not, and the standards applied to an access onto a country lane are considerably more forgiving than those applied to an A road.

The local highway authority, usually the county or unitary council, deals with accesses onto classified roads. Motorways and trunk roads form the strategic road network, where National Highways is the relevant body and is a statutory consultee on planning applications affecting it. Its position is set out in a government circular on the strategic road network, and in practice a new private access onto a trunk road is very rarely accepted at all.

Permitted development rights do not get you around this. Under Part 6 of Schedule 2 to the General Permitted Development Order 2015, agricultural development rights are restricted where the works would be within 25 metres of the metalled part of a trunk or classified road, and the formation of a private way requires prior approval of its siting and means of construction. Read the class before assuming an access is permitted.

Recorded speeds, not speed limits

The single most common error on rural access applications is designing to the posted speed limit. Highway authorities design to recorded speeds, and on a derestricted rural road the recorded speed is often lower than the limit, which helps, while on a 40 mile per hour stretch it is frequently higher, which does not.

The evidence is a speed survey using automatic traffic counters placed in both directions, usually recording over a full week in a neutral period, from which the 85th percentile wet weather speed is derived. Agree the survey location and duration with the highway officer before commissioning it. A survey done at the wrong point on a bend is money spent twice.

Neutral period means avoiding school holidays, August, the Christmas fortnight and any period when the road is affected by roadworks or a diversion. On a rural road carrying harvest traffic, seasonal variation is real and worth discussing with the officer.

Visibility splays and where they are measured from

A visibility splay has two dimensions. The x distance is the set-back from the edge of the carriageway to the driver's eye position in the emerging vehicle, commonly 2.4 metres in lower speed situations and longer where speeds are higher. The y distance is the sight line along the road in each direction, derived from the recorded speed using stopping sight distance.

Manual for Streets provides the method for lower speed streets. Higher speed rural roads are generally assessed using the standards for the wider road network, and the difference between the two at 50 miles per hour is substantial, so establish which applies before you draw anything.

Then the practical questions, which are where these applications fail.

• Is the land within the splay under the applicant's control, or is it a neighbour's hedge? A splay across third party land needs that party's agreement to maintain it clear.
• What height is being kept clear? Authorities specify a vertical envelope, and a 1.2 metre hedge inside the splay is an obstruction.
• Is the splay measured to the nearside carriageway edge or the centreline? This varies and it changes the answer.
• Can the splay be maintained in perpetuity, and will a condition require it?

Removing a length of mature hedgerow to form a splay brings its own problems. Hedgerow removal may need notification under the hedgerow regulations, and the ecological value of the hedge will be raised, particularly where it is a boundary of some antiquity.

Movements, and what kind

Frequency matters, and so does composition. Ten car movements a day from a single dwelling is a different proposition from ten articulated deliveries to a farm shop.

Set out the expected movements by vehicle type and time of day, the swept paths for the largest vehicle using the access, and whether any vehicle would have to reverse onto or off the classified road. That last point is usually decisive. An access that requires a tractor and trailer to reverse out onto an A road will be refused, however good the visibility.

For anything beyond a single dwelling a short Transport Statement covering movements, visibility, swept paths and any accident record on the relevant stretch will answer most of the officer's questions in one document.

Field gates, setbacks and standing space

Where the access is gated, the gate has to be set back far enough that a vehicle can stand clear of the carriageway while the gate is opened. Authorities specify the distance, and for agricultural accesses used by tractors and trailers it is considerably more than for a car.

Gates should open inwards, into the site, never outwards over the highway. The surfacing between the carriageway and the gate should be bound for a stated length so that mud and loose material are not carried onto the road, which is both a highway safety point and a condition you will otherwise receive.

Where the access serves a field used seasonally, consider whether a gate is needed at all. An ungated bellmouth with a cattle grid or a simple barrier set well back avoids the standing space problem entirely.

Drainage and the highway boundary

Surface water must not discharge from the site onto the highway. The usual requirement is a channel or gully across the access, connected to a soakaway or an attenuation feature within the site, with a level arrangement that falls away from the road.

Where the access crosses a highway ditch, it will need a pipe or a culvert sized by the highway authority, with headwalls, and the authority will want to know who maintains it. On a road with an open drainage ditch, this is frequently the most expensive part of the access.

Works within the highway boundary, including the bellmouth, the crossing of the verge and any alteration to the kerb line, are carried out under an agreement with the highway authority rather than under the planning permission, and the process is set out in the note on section 278 agreements, scope, cost and timing.

Talking to the highway authority first

Highway officers will usually discuss an access informally or through the council's pre-application service, and the conversation is worth having before the survey work.

Bring a location plan, the proposed position, the recorded speeds if you have them, and a description of the movements. Ask which visibility standard applies, whether the splay dimensions are acceptable in principle, and what they will want conditioned. An officer who has seen the proposal early is a great deal easier to satisfy at application stage, and the general procedure is covered in the note on getting access onto a classified or trunk road approved.

Where an existing lawful access helps

An existing access with an established lawful use is a real advantage, because the comparison is with what already happens rather than with a blank frontage.

Two cautions. Using an existing agricultural access for a materially different purpose can amount to a change of use even where nothing is built, so the fallback argument needs care. And an authority can still require visibility improvements as a condition of permitting the new use, on the basis that the intensification makes the existing arrangement unsafe.

Where the access has not been used for years and the bellmouth has grown over, expect to be treated as though it were new.

Enter your postcode on PlanScope to see which transport and access documents your site is likely to need. This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it.

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