What Is Visibility Splay & Why Does It Matter?
What is a Visibility Splay?
A visibility splay is a crucial aspect of road safety. It offers a clear, unobstructed view of oncoming traffic, which a driver needs so they can enter or exit a road safely.
Visibility splays are especially important at junctions, driveways, entrances and other points where vehicles join or cross a road. Ensuring a proper visibility splay prevents accidents and helps maintain safe traffic flow.
Why is Visibility Splay Important?
Giving drivers clear sightlines
Vehicles entering or leaving a road must be able to see oncoming traffic in both directions. This ensures they can safely assess when it’s clear to proceed.
Preventing accidents
Without a clear visibility splay, drivers might make dangerous manoeuvres, such as pulling out into traffic they didn’t see due to obstructions.
Meeting legal and planning standards
In the UK, local authorities require proper visibility splays when granting planning permission for new driveways or entrances onto public roads. Failure to meet these standards can result in planning rejections or costly post-construction modifications.
How Visibility Splay Impacts Early Design Decisions
Understanding visibility splay requirements at the start of a project can have a significant impact on the design process, especially for new driveways, entrances, or new developments near busy roads. Addressing these requirements early on can help avoid costly revisions, delays in planning permission, and safety concerns down the line.
Site Layout Adjustments
If your initial design doesn’t allow for the required visibility splay, you may need to reposition entrances or driveways to ensure that sightlines are clear.
For instance, a property located on a bend or near a junction may require the access point to be moved or designed differently to meet the necessary safety standards.
Boundary and Landscaping Design
Vegetation like hedges, walls, and fences are common causes of blocked sightlines. By factoring in visibility splay requirements early on, you can design your landscaping and boundary features in a way that complements safety regulations.
For example, you can avoid placing tall hedges or walls close to a driveway, ensuring that the line of sight remains clear.
Road Access and Safety
If the visibility splay requirements are not factored in early enough, it may result in road access issues, forcing costly redesigns or causing delays in planning approval.
In some cases, a visibility splay that doesn’t meet local regulations might require costly road improvements (such as traffic calming measures) to ensure safety.
Saves Time and Costs
Knowing about visibility splays from the outset allows architects and developers to avoid planning permission delays. If designs don’t meet visibility standards, planning applications may be rejected or require modifications.
By incorporating visibility splay measurements into the design phase, you can avoid the expense of altering construction plans or relocating key access points once work has already begun.
Practical Example
Let’s say you’re designing a new driveway for a rural property located on a busy country road. If you don’t account for the necessary visibility splay early on, you may end up having to shift the driveway entrance, relocate boundary walls, or trim trees that were part of your original landscaping plan. Factoring in the required sightlines during the design phase allows for smoother planning approval and keeps construction on track.
Common Visibility Splay Issues
Overgrown Vegetation
Over time, hedges, trees and other vegetation may obstruct sightlines. If you’re redesigning or planning new landscaping, ensure features with the potential to grow much larger are placed in areas that won’t impact visibility splay.
Dangerous Parking
Vehicles parked too close to junctions can obscure sightlines and make it dangerous for other drivers to enter the road. If you’re planning a new development, consider whether you can incorporate ways to prevent this. This might include adding pinch points or small pedestrian refuge islands that prevent any illegal parking. You could also install raised planters or bollards near junctions.
Changes to Surrounding Property
New buildings, extensions, walls or fences built can obstruct visibility. Some residential property owners also install driveways without considering sightlines. This can create dangerous access points, particularly on busy or fast-moving roads. Property owners and architects should ensure any changes won’t compromise safety.
Ensuring Safe Road Access with Visibility Splays
A visibility splay isn’t just a legal requirement – it’s a vital part of road safety. Whether you’re planning a new driveway or large-scale development, ensuring clear sightlines at road junctions is essential for preventing accidents and maintaining smooth traffic flow.
If you’re planning any access onto a public road, a land surveyor can provide site surveys to support assessments that check your visibility splay meets UK standards.
