National Roads Development Guide :Proposed Argyll and Bute Local Amendments

NOTE : THIS IS A DRAFT AND IS NOT OPEN FOR CONSULTATION. ITS PURPOSE IS TO ASSIST IN CONSIDERATION OF SG LDP TRAN 4

2.2.5 Street Layout b) Presumption will be in favour of horizontal deflection for traffic calming. Vertical deflection will only be accepted in exceptional circumstances.

Visibility requirements.

The normal requirements for visibility distances are set out below.

X – distance (m)

The ‘x’ – distance is 2.4m.

Y – distance (m) and Forward Visibility Distance (m)

The ‘y’ distance is based on a) the speed of the traffic on the public road, to ensure drivers can react in time to avoid a collision and b) the expected traffic flow on the public road, to avoid the need for traffic on the public road to slow down or stop in order to avoid a collision.

For quiet roads, Table 1 should be used. For Strategic Routes and other routes carrying traffic volumes greater than 3000 vehicles per day (vpd), use Table 2. See below for a list of Strategic Routes and those carrying higher volumes of traffic.

Table 1 Lightly Trafficked Roads

Public Road

Vehicle Speed (mph) 60 50 45 40 35 30 20

‘Y’ dimension

136 103 84 75 53 42 25

Table 2 Strategic and Heavily Trafficked Routes

Public Road

Vehicle Speed (mph) 60 50 45 40 35 30 20

‘Y’ dimension

160 120 95 75 53 42 25

2.1 Traffic volumes are in vehicles per day (vpd) and refer to the total combined flow in both directions.

2.2 Where actual speed falls between the given values the y – distance may be interpolated by the Roads Authority.

2.3 The traffic speed to be used is the 85%ile speed on the public road. This will be measured or estimated by the Roads Authority.

2.4 Applicants should note that they must either own or obtain control of the land contained within a visibility splay, except when it is already controlled by the Council as part of the public road corridor. Control must be obtained through an agreement, in accordance with Sect 75 of the Town and Country Planning (Scotland) Act 1997, to ensure that the visibility splay remains free of obstruction in perpetuity.

Primary Routes in Argyll

Trunk Roads

A82 Glasgow to Fort William and Inverness

A83 Tarbet to Kennacraig

A85 Perth to Lochearnhead to Crianlarich and Tyndrum to Oban

A828 Connel to Ballachulish

Applications where access onto public road will be onto a Trunk Road are processed by Scotland TranServ Ltd. on behalf of Transport Scotland and may be subject to different criteria.

Strategic Roads Maintained by Argyll & Bute Council as Roads Authority

A83 Kennacraig to Campbeltown

A814 Dumbarton to Arrochar

A815 Cairndow (A83) to Dunoon to Toward

A816 Lochgilphead to Oban

A818 Arden Roundabout (A82) to Helensburgh

A819 Inveraray to A85 at Dalmally

A885 Dunoon to Sandbank

A886 Rhubodach-Kames Castle Road

A844 Bute Circular Port Bannatyne

A886 Colintraive to Strachur

A817 Haul Road

A848 Salen to Tobermory

A849 Craignure to Salen

B833 Rosneath Peninsula

B872 Garelochhead Road

B838 Church Road Arrochar

Shore St, Oban

Albany St, Oban

Other routes are classified as being lightly trafficked routes. However, the higher standard of visibility requirement may be required under certain circumstances e.g. when there are very high traffic flows at certain times of the day which are not reflected in the Annual Adjusted Daily Flows. (AADF).

2.2.6 Road and Lane Widths

Carriageway widths should be designed to be specifically single track or double track and exclude dimensions which are in between. Single track roads should be designed to be 3.25 – 3.5m wide. Provision for pedestrians & cyclists must be considered where single track roads are proposed. Double track roads should be a minimum of 5m wide. This width is only suitable in residential areas which are not likely to become bus routes and have very limited commercial vehicle traffic. Where carriageways are built at the minimum width, swept paths and curve widening must be taken into consideration. This consideration required to reduce footway and verge

damage from overrun and not for the expedience of free flow of traffic at higher speeds. Refer to 3.1.3

2.3.8 Adoption of SUDS

Any part of a SUDS scheme that is constructed under a Road Construction Consent (RCC) must be designed to require minimal maintenance.

Access for and methods for maintenance must be included in the overall design. Wayleaves, in perpetuity, for access to any installation that is out with the Road Corridor must be provided by the developer. Such accesses must be of a suitable standard to reduce damage to the area by plant and the like, when access is required.

2.4.2 a) xiii) All plans showing adoption boundaries must include all land associated with any required visibility splays. Any off site road drainage arrangements must have suitable designated access routes, secured by leases in perpetuity.

3 Details

3.1.1 c) Stopping sight distances and visibility splays are specified for Argyll & Bute, see section 2.2.5 b)

3.1.3 Minimum road widths should be 5m for double track roads and 3.25 – 3.5m for single track roads, provided provision is made for pedestrians and cyclists to use the road safely. See 3.1.4.

Passing places on single track roads will be required at a maximum spacing of 150m and are required to be inter-visible.

3.1.1 d) Junctions of new minor roads and private access should not be steeper than 5% (positive or negative) over the first 6m, where access gradients beyond this distance are significantly steeper, then the access must be arranged such that an errant vehicle cannot proceed directly onto the public road, being joined. It must be retained within the curtilage of the property.

3.1.4 Pedestrian & Cyclists

Developments of up to 5 dwellings will be served by private accesses. Developments of 6 or more dwellings will be served by a road to adoptable standard.

In rural and island areas where traffic volumes are low and the road network is predominantly single track, small developments of 6 – 10 dwellings (incl) may be served by a reduced standard of Road.

The Road will still require Construction Consent. The may be single track with passing places, spacing as per 3.1.1 c).

Street light will generally not be required but the Roads Authority may require a cable duct to be installed. However, where the roads serving the entrance to the new development are furnished with lighting then lighting should continue into the new development.

Footways and kerbs may also be omitted but positive drainage must be provided. Pedestrians and cyclists must be provided for to allow safe practical refuge from vehicles. Verges must be wide enough, flat and uniform enough to provide adequate step off. Verges should be hardened to reduce damage from vehicles. Satisfactory edge support must be proved for the carriageway, either in the form of a concrete haunch or, where ground conditions a favourable , a flexible haunch.

Passing place design is shown in Fig 26.

3.4.2 Specifications

The specifications for material qualities, to be incorporated in any road to adoptable standard shall be those contained in DMRB HD 26/06.

3.4.4 a) Pavements

For soils with a CBR that is greater than 2% the overall construction depth of the carriageway will be 450mm or greater where a capping layer is required. Where capping layers are non-frost susceptible subbase layers may be reduced by 150mm i.e. where no capping layer is required the minimum subbase depth will be 325mm, where non-frost susceptible capping is used the minimum subbase depth will be 275mm. Binder course will be a minimum depth of 85mm bitumen macadam and surface course will be minimum of 40mm high stone content asphalt or 40mm enhanced bitumen content macadam or 40mm hot rolled asphalt.

3.4.9 Drainage & SUDS

Bedding mortars for all covers and brickwork to gullies and manholes will be a polymer modified mortar Spec******

All concrete used in connection with manholes and gullies, excluding blinding and underground pipe haunching will be minimum class ST4 or equivalent.

3.4.11

Street lights will generally not be required but the Roads Authority may require a cable duct to be installed. However, where the roads serving the entrance to the new development are furnished with lighting then lighting should continue into the new development.

3.5 Parking Requirements

The numbers of spaces required for specific types of development are detailed in Argyll & Bute Council’s Local Development Plan (LDP) Supplementary Guidance. Where any development type is not included in the LDP then the Roads Authority should be consulted.

3.5 f) Attached garages cannot be considered in the calculation of available in curtilage parking spaces.

3.7 see 3.5 above.