Forward visibility on a bend for a new access

Forward visibility bend access problems are the quiet killer of rural self-build applications. The junction visibility splay out of your drive can be perfect and the application still fails, because a driver coming round the bend on the main road cannot see your access, or the car emerging from it, in time to stop. That is a different geometric test, measured along the carriageway rather than out of the access, and it is tested against the same stopping sight distance derived from measured speeds.

The good news is that it is usually fixable. But the fix often involves land you do not own.

What forward visibility measures

Junction visibility asks what a driver in the access can see. Forward visibility asks what a driver on the through road can see ahead of them as they travel round the curve.

The measurement is taken along the carriageway, conventionally along the centre of the nearside lane, between two points separated by the required stopping sight distance. The line between those points has to be clear of obstruction. On the inside of a bend, that line cuts across the verge, the bank, the hedge or the wall, which is exactly where the obstruction sits.

The required distance is the same stopping sight distance used for a junction splay, derived from the measured speeds rather than the posted limit. On a lane signed at 60 mph where traffic runs at 28 mph, the distance needed is modest. On a 30 mph road where traffic runs at 34 mph, it is longer than the standard table for the limit suggests.

Setting it out on the inside of a bend

The drawing is simple to produce and simple to check, which is why authorities take it seriously.

1. Establish the measured 85th percentile speed for each direction of approach and convert it to a stopping sight distance.
2. Plot the centre line of the nearside lane on a scaled topographical survey through the full extent of the bend.
3. Take a point on that line at the position of the hazard, usually the access itself.
4. Step back along the line by the stopping sight distance to the driver's position.
5. Draw the straight line between those two points, and sweep it through intermediate positions to produce the envelope that must be clear.
6. Show every obstruction inside that envelope, with its height and its ownership.

The envelope, not the single line, is what matters. A hedge trimmed to clear one sight line can still break the view from a position five metres further back, which is why the sweep has to be drawn rather than sampled.

Annotate the drawing with the speed survey date, the source of the sight distance figure and the heights used for driver eye and object. Authorities reject access drawings that assert visibility without showing the derivation far more often than they reject the geometry itself.

Verges, banks and hedgerows in the way

The typical rural obstruction is a hedge on a raised bank, and it presents three separate problems.

Height is the obvious one. A hedge cut to 0.9 metres on a bank 0.8 metres above carriageway level still blocks the sight line. The bank has to come down, and that is earthworks on someone's land rather than a trim.

Ownership is the second. Hedges on the boundary may belong to the adjoining landowner, to the highway authority, or to nobody with a clear title, and the verge is frequently highway even where it looks like part of the field. Ask the highway authority to confirm the extent of highway land before you assume anything.

Protection is the third. A hedgerow may be an important hedgerow under the Hedgerows Regulations 1997, in which case removal requires notice to the local planning authority, which can refuse it. Trees in the hedge may be protected by a Tree Preservation Order or by conservation area status. Birds nesting in the hedge are protected during the breeding season, which runs from March to August, so timing matters.

Removing obstructions you do not own

Three mechanisms exist, and they vary in reliability.

The highway authority has powers to deal with vegetation that obstructs the highway or interferes with visibility, including serving notice on an owner to cut back hedges and trees under the Highways Act 1980. Authorities use those powers for existing safety problems, not usually to enable a private development, so do not plan around them.

An agreement with the adjoining owner is the ordinary route: a deed granting the right to cut back and maintain, or the purchase of a strip. Get it in writing before determination, because an authority will not grant permission on the strength of an expectation.

Works within the highway itself, including lowering a bank or regrading a verge, need the highway authority's agreement and are usually delivered under a highway works agreement that follows the permission. The note on section 278 agreements explains how that sequencing works.

Relocating the access as the better answer

Moving the access is often the solution that costs least and takes least time, and it is the one applicants resist longest because the original position is usually the most convenient.

Look for a position where the carriageway is straight, where the frontage is set back from a bank, or where an existing field gate already has a history of use. Even twenty metres along a frontage can transform the geometry on a bend, because the sight line no longer has to cut across the inside of the curve.

Test two or three positions before settling. An access that needs no third party land, no bank reduction and no hedgerow removal notice will be determined far faster than one that needs all three, even if it means a longer driveway.

Where a scheme has multiple plots, consider a single shared access at the best geometric position rather than separate accesses at convenient ones. Highway authorities prefer fewer access points, and the visibility case only has to be made once.

What to submit

For a single dwelling the access package is normally a speed survey, an access and visibility drawing showing both the junction splay and the forward visibility envelope with dimensions, a plan showing land ownership and control over everything inside those envelopes, evidence of any third party agreement, and a short written derivation. A Transport Statement is the usual home for that material on a small scheme.

Record protected vegetation properly. Where trees or hedges inside the envelope are protected or have amenity value, the application should include a tree survey so the authority can weigh the loss against the highway benefit rather than discovering it at the site visit.

The refusal reasons this answers

Two reasons recur on small access applications in the countryside: inadequate visibility for the speed of traffic, and reliance on land outside the applicant's control. Both are evidential.

A speed survey answers the first by establishing the real design speed. A drawing with an ownership overlay answers the second, or proves that it cannot be answered from the proposed position, which is the point at which relocation becomes the obvious move rather than a concession. Where the main road is a trunk road, the position is different again and the strategic road network authority becomes a statutory consultee, as set out in the note on when National Highways objects.

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.