Visibility splay assessment
An assessment of visibility for drivers at a new or altered access.
About this service
A visibility splay is the triangle of clear sight a driver needs when emerging from an access onto a road. It is defined by two distances: how far back from the road edge the driver sits, known as the x distance, and how far along the road they need to see approaching traffic, known as the y distance. A wall, hedge or parked car within that triangle can block the view.
Highway authorities ask for splays whenever a new access is created, or an existing one is altered or used more intensively. That includes new driveways, mews and backland access roads, and the entrances to small residential developments. Pedestrian splays matter too. Where a driveway crosses a footway, drivers need to see people walking along it, particularly children, before the bonnet is out over the pavement.
Our assessment measures the actual conditions on site, sets the splays against guidance appropriate to the road type and speed, and shows the result on a clear drawing. It goes through our three-step quality control process, with final sign-off by our Head of Engineering. Where the access will also be used by larger vehicles, we can add a swept-path analysis to the same drawing set.
When you need it
- You're creating a new access or junction
- The highway authority needs visibility splays shown
What's included
- Site measurements
- Visibility splay assessment to relevant standards
- Drawings
How it works
- Review the roadWe look at the type of road, its speed limit and likely traffic speeds, parking patterns, and the position of junctions and other accesses near the proposed entrance.
- Measure on siteWe measure the access position, boundary walls, hedges, trees, lamp columns and other obstructions, and confirm which land is within your control or part of the public highway.
- Assess the splaysWe set the x and y distances using guidance suited to the street, such as Manual for Streets on most residential roads, and check both vehicle and pedestrian splays.
- Draw and reportWe produce a drawing showing the splays and any obstructions, with a short note explaining the standards used and any changes needed, such as lowering a wall.
What you receive
Getting the x and y distances right
On most residential streets, councils use the guidance in Manual for Streets, where the y distance is linked to the stopping distance for the speed of traffic. On a typical 30 mph street that is around 43 metres, with shorter distances where speeds are genuinely lower. The x distance is commonly 2.4 metres, sometimes reduced on quiet streets. Faster or busier roads may be assessed against stricter standards, and the highway authority will confirm which apply.
The splay must fall over land you control or the public highway, and it must stay clear permanently. A neighbour's hedge or wall within the splay is a problem you cannot solve without their agreement, and councils often add a planning condition requiring the area to be kept free of obstruction. If your access is a simple domestic driveway, our dropped kerb package includes the visibility checks the council needs.
Frequently asked questions
What is a visibility splay?
It is a triangular area at an access or junction that must be kept clear so drivers can see oncoming traffic and pedestrians. It is measured from a point set back from the road edge, along the road in each direction. Walls, hedges, fences and planting within it are usually limited to a low height.
Do I need a visibility splay for a new driveway?
Usually yes. Councils normally want to see that a driver leaving the driveway can see along both the road and the footway. For a domestic crossover the check is often straightforward, but on busy roads, near junctions or where boundary walls are high, the highway authority may want a formal assessment and drawing before approving the access.
What height can a wall be within a visibility splay?
Councils typically restrict anything within the splay to a low height, often around 600 millimetres, so a driver can see over it. Some authorities set a different figure for pedestrian splays. The highway authority will confirm the requirement for your road, and a planning condition may require the area to be kept clear permanently.
How much does a visibility splay assessment cost?
Our visibility splay assessment starts from £250 + VAT, including site measurements and a drawing. Sites with several accesses, or where speed surveys are needed, may cost more. Every job starts with a fixed fee confirmed in writing before any work begins, and our typical turnaround is 10 working days.