Technical design information for highway developers

Documents required as a minimum

  • S38/278 Works agreement drawing
  • Roadworks Construction details
  • Drainage Construction details
  • Drainage general arrangement
  • Drainage calculations
  • Gully catchment areas
  • Streetlighting
  • Longsections/cross-sections showing gradients
  • Drawings showing vis-splays
  • Surface material layout
  • Swept Path Analysis using 11.2m refuse vehicle
  • Traffic signals and communication (CCTV) designs
  • Ground Investigation report
  • Combined utilities drawing
  • Pre-start site picture survey of existing highway network

Standard details

  • All kerbing, edging and channel blocks to be laid on and backed up with ST4 concrete
  • All kerbing, edging and channel blocks to be laid on a minimum of 350mm wide race
  • All kerb faces to be a minimum 125mm upstand
  • All kerb faces at private vehicle crossovers to be between 20-25mm upstand
  • All kerb faces at pedestrian crossovers to be between 0-6mm upstand
  • Footway construction to be a minimum of 20mm Surface Course, 50mm Binder Course & Sub base 200mm
  • All driveway crossovers which are serving 3 or more dwellings must be strengthened to 20mm (AC6) Surface Course, 60mm (AC20) Binder Course, 120mm (AC40) Base Course & 250mm Type 1
  • Blockwork to be 80mm thick in carriageway and 60mm thick in footway
  • Blockwork roads binder course to be punctured at 1 metre intervals starting 500mm from each kerb line and filled with pea shingle to act as drainage medium
  • Blocks to be laid on maximum 30mm sand course – 2no. course of stretcher bond for carriageway. Chamber surrounds within carriageway at 2course surrounds also. 45 deg Herringbone pattern using Brindles
  • If utilities are to run underneath Permeable blockwork carriageways, they must be in their own impermeable service corridors
  • Sub base to be quarried Type 1, in rare circumstances we will accept recycled, but each load must be inspected prior to laying
  • Capping material to be 6F1 NOT 6F2
  • PSV on approaches to crossings roundabouts etc. to be a minimum 68 PSV
  • Tactiles – see DETR ‘Guidance on the use of Tactile Paving Surfaces’
  • Speed Cushions & Tables 75mm max height - max Gradient 1 in 8. On bus routes, 60mm max height and preferred gradient 1:15
  • Ramps to be constrained with kerbs top and bottom and not to be constructed using blockwork
  • Formation to be covered with Geotextile prior to laying Capping/Sub-base course
  • All utility covers in adoptable areas to be ductile material – not plastic
  • Steps are only accepted in highway land if an alternative accessible route is also constructed
  • Private parking bays are accepted even if surrounded by highway land; they must not however, drain water onto highway land
  • Steep gradients should be minimised when possible. Where the footway follows the longitudinal fall of the carriageway then consideration must be given to maximum gradients and lengths, to ensure that the footway remains accessible to people with disabilities

Water Authority boundary box covers must not be placed within adoptable vehicular crossovers. To overcome this the covers must be placed either on private land or moved away from the crossover location such that they are not adjacent to a dropped or transition kerb.

A complete resurface of half the existing carriageway will be required the full extents of all Section 184 and Section 278 works to ensure a sufficient tie-in to existing public highway.

Drainage details

  • Side Hinged Gulleys only – D400 loading
  • 150mm Deep Chamber covers only - D400 loading
  • Gulley pots to be cast concrete 1050mm deep
  • Gulleys to discharge into chambers or arrange collection of commuted sums
  • Gulley connections - 12m max pipe length
  • Gulley surround to be ST4 Concrete
  • Maximum of two brick courses between the gulley pot and the gulley cover/grate
  • Any proposed gullies to be installed must not be located in-front of driveway crossovers
  • The number of Gulleys provided will depend upon the gradient of the carriageway
  • Normally at least one gulley per 200m2 of carriageway for gradients between 1% and 3%, one per 150m2 for carriageway gradients between 3% = 1:30 and 5% = 1:20 one per 100m2 for carriageway gradients exceeding 5%. = 1:20 Double gulleys in low points
  • External face of inspection chambers to be 0.5 m from kerbline
  • Pipes to be a minimum of 1m from kerbline
  • Pipes within 1200 of surface level in carriageway must have concrete cover
  • Pipes within 900 of surface level in footway & verge must have concrete cover
  • Concrete cover must have flexible joints at pipe joints
  • No private water into highway system
  • All existing and proposed utilities must be below formation level of footway/carriageway construction, and comply with NJUG recommended guidelines
  • Catchpit sumps to be a minimum of 300mm deep
  • Soakaways to be a minimum of 5m from a footway or carriageway

Street lighting

  • Streetlights and cabling must be in highway
  • Traffic Calming features require Highways Spec lighting – not Parish

Highway design

Provide chainages on relevant plans.

  • No vision splays to be across Non Highway land – regardless of private property planning conditions.
  • Use standard radius sizes where possible. Minimum 6m on new accesses except where we accept MFS spec tight junction radii with Carriageway depth construction footways either side to reduce approach speeds on access to shared space side roads
  • Footway crossfall 1:40 or 2.5% for crossovers in footway
  • Private VX max crossfall 1:12 or 8%
  • Carriageway Crossfalls 1:40 2.5%
  • Carriageway minimum longitudinal gradient 1:200
  • Verges to be a maximum of 1:3 without stabilisation
  • Width of shared surface in general 5.5m minimum
  • Carriageway widths minimum 4.8m 2 way, with 2m footway one side & 1m maintenance strip the other – with exception of localised narrowing. Narrowings of 2.75m to 3.25m should be avoided to avoid motorists conflicting with cyclists
  • Max width if single lane carriageway 3.5m or hatched if over (to stops cars trying to squeeze past cyclists)
  • Min distance between back edge of f/w or c/w to significant drop = 1m flat
  • Footway widths - 1.8m min (2m preferred) however if available widths are restricted we will accept a 2m footway one side with a 1m service margin opposite
  • Verges/maintenance strips to be grass, bollards and full height kerbs will be required to deter parking damage
  • Verges/maintenance strips to be 1m wide
  • Where verges/maintenance strips are hardened pedestrian deterrent paving is to be used so that they are not confused as sub-standard width footways
  • Highway delineation to be installed where extents are not obvious. Continuous edgings or Highway Boundary markers to be used
  • Controlled crossing points to be 4m wide
  • Any entrances to or from shared space roads or at junctions within shared space roads should have some indication within the carriageway to enable the visually impaired to orientate themselves. Suggestions are: raised tables, changes in surfacing, rumble strips etc

Highway signage

  • All direction signage to be designed by a signage manufacturer and submitted for approval
  • Non illuminated signage to be on galvanised posts


All roundabout designs to include details of:

  • Inscribed Circle Diameter
  • Entry Path Curvature on each arm. Entry Angle (s)
  • Entry Width
  • Approach Half Width
  • Entry Kerb Radius
  • Exit Kerb Radius
  • Effective Flare Length
  • Visibility (s)


All junction designs to include details of:

  • Design speed limit
  • SSD
  • Turning length (a)
  • Deceleration length (b)
  • Through lane width (c)
  • Turning lane width (d)
  • Direct taper length (e)

Last updated 10 January 2023