Highways Access Appraisals, Visibility Splays and Swept Path Reports
Securing a safe and policy-compliant vehicular access is frequently the single most critical hurdle in obtaining planning permission. When a full Transport Statement is disproportionate to the scale of your scheme, Local Highway Authorities regularly instruct applicants to submit a targeted Highways Access Appraisal (also known as a Highway Access Appraisal or Highways Technical Note). Southwest Environmental Limited prepares robust, fixed-fee Highways Appraisals to de-risk planning applications, overcome highway officer objections, and discharge pre-commencement planning conditions across the UK.
What Does a Highways Access Appraisal Include?
Under the National Planning Policy Framework (NPPF), planning authorities must ensure that safe and suitable access to a site can be achieved for all users before granting consent. Our engineers combine on-site highway audits with 2D/3D CAD design to provide the exact empirical evidence Local Highway Authorities require:
Visibility Splay Assessments (MfS & DMRB): Calculating and plotting accurate "X" and "Y" visibility splays in CAD to prove unobstructed intervisibility between emerging drivers and oncoming traffic, strictly compliant with Manual for Streets (MfS) for 20–30mph roads and the Design Manual for Roads and Bridges (DMRB) for 40mph to 60mph rural corridors.
Swept Path Analysis (Vehicle Tracking): Running CAD vehicle manoeuvring simulations to prove that fire tenders, refuse collection vehicles, delivery vans, agricultural machinery, or private cars can enter, turn within, and exit the site in a safe forward gear.
Access Geometry, Gradients & Footways: Designing bellmouth radii, dropped kerbs, passing bays, access ramp gradients, and assessing the provision of footways to ensure vehicles and pedestrians can access the highway safely.
Highway Boundary & Collision Data Review: Verifying adopted highway land extents with the county council so sightlines do not cross third-party land, alongside reviewing 5-year Personal Injury Collision (PIC) records to demonstrate baseline road safety.
Speed Surveys & Baseline Traffic Counts: Where existing hedgerows, stone walls, or road bends restrict standard visibility splays, we deploy Automatic Traffic Counts (ATC) and CCTV Junction Surveys to record actual 85th percentile wet-weather traffic speeds, enabling us to justify shorter, achievable sightlines.
Local Authority Expertise: Dorset, Devon, Somerset & Nationwide
You may have been asked to provide a Highways Access Appraisal by your case officer if you are submitting a planning application in Dorset, Devon, Somerset, Cornwall, Wiltshire, or Gloucestershire, where winding rural alignments, steep roadside banks ("Devon banks" and sunken lanes), and mature hedgerows create unique visibility challenges. For instance, on cross-border rural corridors such as the B3165 between Lyme Regis (Dorset) and Uplyme (East Devon), steep topography and changing speed limits require careful vertical and horizontal sightline modelling alongside topological surveying.
We regularly prepare appraisals tailored to the specific local validation checklists and highway design guides of:
South West Highway Authorities: Dorset Council, Devon County Council (including East Devon, Teignbridge, South Hams, Mid Devon, and North Devon), Somerset Council, Cornwall Council, Wiltshire Council, Bristol City Council, Bath & North East Somerset (B&NES), and South Gloucestershire Council.
Regional & National Authorities: High Peak and Derbyshire County Council, Lancashire County Council, West Yorkshire (Bradford and Leeds), Lincolnshire, Hampshire, Surrey, Essex, and Greater London boroughs.
Typical Projects Requiring a Highways Appraisal
A standalone Highways Access Appraisal is the fastest and most cost-effective solution for developments that fall below the threshold of a major Traffic Impact Assessment, including:
Small Residential Schemes (1 to 9 Dwellings): Infill plots, self-build homes, backland developments, and outline "Call for Sites" or Grey Belt land promotions where principle of access must be proven upfront.
Class Q Barn Conversions & Rural Diversification: Demonstrating safe intensification of an existing agricultural field gate for residential conversions, holiday lets, glamping sites, or equestrian facilities.
Forestry, Agricultural & Commercial Accesses: Designing new bellmouths and visibility splays for timber lorries, tractor-trailers, solar farms, and commercial yard extensions, supported where necessary by CBR Testing for heavy-duty access track and pavement foundation design.
Integrated Transport, Active Travel and Environmental Support
Unlike single-discipline highway drafters, Southwest Environmental Limited integrates your access design with wider planning and environmental deliverables under one roof. Where visibility splay creation requires cutting back roadside banks or hedgerows within National Landscapes (AONBs), we coordinate the highway geometry sympathetically with arboricultural, ecological, and landscape constraints.
Southwest
Environmental Limited