Junction type, geometry and spacing

 

For guidance on active travel crossings at side roads please see the Active Travel Section of the LHDG.

Content:

Principles of junction provision

Basic junction forms should be determined at the concept layout (master planning) stage with the more detailed proposals provided as the development proposal evolves. 

Whilst Figure 7.9 of Manual for Streets identifies a range of possible junction types, The council expects junctions designs to be in the form of:

  • a priority T-junction;
  • a staggered priority junction at a 90° angle to the main road;
  • a mini-roundabout. Mini-roundabouts are acceptable where they form part of a more comprehensive traffic-calming scheme that is either required to reduce the development’s impacts or that has previously been identified. 

The council recognises that for roads with high expected flows and/or speeds, or site accesses that require a high level of operational capacity, a compact / full roundabout or signal controlled junction may be required.  Such circumstances will be considered on their own merits and the council recommends early discussions in this respect.  

Any design that deviates from the council’s expected layout above should be accompanied by a designer’s risk assessment to ensure the safety of the junction is not compromised. The council reserves the right to refuse to adopt roads where it is considered junction design is inappropriate.

Provision of priority-controlled (‘give way’) crossroads should be avoided. In circumstances where directly opposing junctions are the only option, a justification for their use must be made to the council. In this context, the provision of a roundabout controlled junction would be the expected form of control.

Priority junction provision

Table 9 below shows the expected geometric requirements for all priority junctions within different development types including external junctions including, subject to circumstances. Please also refer to Materials and ConstructionSigning and Lining”. 

Please note that, where a corner radius is less than 7.5m, footway strengthening must be provided. Please see Materials and Construction “Road Pavement”.

Table 9: Priority junction geometric requirements 
Development type Road type Corner radii (metres)
Residential Entry to a Residential access way or road or junction between access ways and roads 6m

Industrial and commercial 

Use class B1 offices

Entry to Minor industrial access road or junction between access roads 6m
Industrial and commercial Other B1 uses Entry to Minor industrial access road or junction between access roads 10m

Industrial and commercial 

Use classes B2 to B8

Entry to Major industrial access road or junction between access roads See Figure 9 below


 

Image
diagram showing the priority junction geometric requirements

Figure 9: Priority junction geometric requirements

Development types not listed will be considered on a site-by-site basis.

Radii based on road widths set out in Table 3 and Table 4, where roads meet at an angle of 90 degrees. For other circumstances (including any proposals for tighter radii), tracking assessments will be required (see paragraph 3.21) of the proposed layout.

Other factors will be considered in assessment of the junction proposals, including the likelihood of on-street parking problems in the vicinity of the junction and whether the roads are likely to form part of a bus route.

Junction spacing

Road junctions on the same side of a road should be spaced so that a vehicle waiting to enter the main road at one does not interfere with visibility for a vehicle waiting at another.

Opposite side spacing should be half of the forward visibility required for same side junctions.

Image
diagram showing correct and incorrect junction layout spacing

Figure 10: Junction spacing

Private access restrictions

Vehicle access should not be provided:

  • within the vicinity of the junction, with consideration of the status of the major road (in terms of class, daily volume, 85th percentile etc.);
  • on to the corners (radii) of the junction;
  • at bus stops or lay-bys;
  • close to a pedestrian or cycle refuge;
  • close to a traffic-calming feature (accesses should not be sited on the ramp of a road hump or speed table due to the risk of a vehicle grounding as it manoeuvres into or out of the access); and
  • close to street furniture (see Materials and Construction Street Furniture and Art”).
  • Where vehicle movement is the primary function of highway (distributor road or similar).

Accesses will normally be acceptable where they comply with LHDG policy in relation to safety and functioning of the highway network and the National Planning Policy Framework. Junctions must also comply with the guidance on the design of private accesses

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