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WILTSHIRE COUNTY COUNCIL Department of Environmental Services SPECIFICATION AND NOTES FOR GUIDANCE FOR HIGHWAY WORKS BY DEVELOPERS UNDER AGREEMENT Eigth Edition - May 2003 Contents Page NOTES FOR GUIDANCE AND PROCEDURE 3 SPECIFICATION 21 APPENDIX A Contact Numbers and Map showing Area Numbers 35 APPENDIX B Application for entering into a Section 38 Agreement (Form 1A) 39 APPENDIX C List of Applicable British Standards 41 APPENDIX D Design and Specification Drawings 43 Further copies of this document are available from the Administration & Information Services Section, Department of Environmental Services, County Hall, Trowbridge BA14 8JD Tel: 01225 713300 NOTES FOR GUIDANCE AND PROCEDURE Contents 1 GENERAL NOTES 5 1.1 GENERAL POLICY 5 1.2 INDUSTRIAL ESTATE ROADS 5 1.3 ADVANCE PAYMENTS CODE 5 1.4 SECTION 38 AGREEMENT 5 1.5 CONSENTS 5 1.6 INITIAL CONSULTATION 6 2 PROCEDURE FOR ENTERING INTO A SECTION 38 AGREEMENT 7 2.1 COMPLIANCE WITH THE SPECIFICATION 7 2.2 DRAWING REQUIREMENTS 7 2.3 SOILS TESTING 8 2.3.1 General 8 2.3.2 Road Design 8 2.3.3 Soils Testing Specification 9 2.4 GEOTECHNICAL DESIGN 9 2.4.1 Earthworks 9 2.4.2 Soakaways 9 2.4.3 Reinforced Soil Structures and Earthworks 9 2.5 STREET LIGHTING 9 2.6 STRUCTURES 10 2.6.1 Site Investigation 10 2.6.2 Design 10 2.7 FINAL DRAWINGS 10 3 NOTES ON DESIGN AND PREPARATION OF DRAWINGS 11 3.1 ROADWORKS DESIGN 11 3.1.1 Footway Edging 11 3.1.2 Pedestrian Crossing Points 11 3.1.3 Boundary Hedges 11 3.1.4 Widening of Existing Carriageway 11 3.2 SURFACE WATER DRAINAGE 11 3.2.1 General 11 3.2.2 Outfall and Easements 12 3.3 STREET LIGHTING 13 3.4 STRUCTURES 13 3.5 TRAFFIC SIGNS AND ROAD MARKINGS 13 3.6 PUBLIC RIGHTS OF WAY 14 -3 - 3.7 LANDSCAPING 14 3.7.1 Design 14 3.7.2 Post-adoption Maintenance Responsibilities 14 3.7.3 Plant-material selection 14 3.7.4 Restrictions on planting 14 3.7.5 Code of Practice for Trees 15 3.7.6 Tree Surgery 15 3.7.7 Recommended Trees and Shrubs 15 3.7.8 Specification 15 3.8 ENVIRONMENTAL BARRIERS 16 4 APPROVAL OF DRAWINGS AND COMPLETION OF AGREEMENT 17 4.1 APPROVAL OF DRAWINGS 17 4.2 BOND 17 4.3 SUPERVISION CHARGE 17 4.4 ADVANCE PAYMENTS CODE 17 4.5 AMENDMENTS TO DRAWINGS 17 5 CONSTRUCTION AND SUPERVISION OF WORKS 18 5.1 NOTICE OF COMMENCEMENT OF WORKS 18 5.2 WORKS WITHIN EXISTING HIGHWAY 18 5.3 STATUTORY UNDERTAKERS SERVICES 18 5.4 INSPECTION AND SUPERVISION OF WORKS 19 5.5 PART 1 CERTIFICATE 19 5.6 OCCUPATION OF BUILDINGS 19 5.7 MAINTENANCE OF WORKS 19 5.8 COMPLETION OF WORKS 19 5.9 'AS CONSTRUCTED' DRAWINGS 20 5.10 FORMAL ADOPTION 20 TABLE 1 - ROAD TYPES 20 - 4 - 1 GENERAL NOTES 1.1 General Policy As a general policy, the County Council require all new residential estate roads serving more than two dwellings on greenfield sites and five dwellings on permitted infill sites to be constructed in accordance with the County Council's Specification and on satisfactory completion to be adopted as publicly maintainable highways. 1.2 Industrial Estate Roads Industrial estate roads are not generally accepted for adoption by the County Council unless they serve premises to which the public require regular access e.g. retail development or on mixed developments. If, however, the developer is unaware of the type of development at the time of construction and feels it desirable for the works to be designed and constructed to adoption standards, the usual Section 38 procedures can be followed, except, of course, for final adoption, upon payment of the appropriate administration and supervision fee. 1.3 Advance Payments Code Upon notification by a District Council of the granting of consent under Building Regulations, the County Council may, within six weeks of that consent, serve a notice under the Advance Payments Code (Highways Act, 1980 - Sections 219 to 225) requiring the deposit of money to cover the estimated cost of constructing the roads and footpaths on the development. It is an offence to commence building works fronting the new street(s) without having first paid the sum demanded under the Advance Payments Code, or having entered an agreement under Section 38 of the Highways Act, 1980 to secure completion of the works. 1.4 Section 38 Agreement When a developer wishes to secure adoption of highway works on a new development, they should enter into an Agreement with the County Council under Section 38 of the Highways Act, 1980. This ensures that the works are constructed to the County Council's Specification; is supported by a Bond to cover the estimated cost of the works; and guarantees eventual adoption provided the terms of the Agreement are satisfied. 1.5 Consents Before a Section 38 Agreement can be completed, the following consents must be obtained (where applicable): - i) Planning permission from the appropriate Planning Authority. ii) Discharge Consent for any highway drainage outfall from the Water Authority and/or The Environment Agency. iii) Orders made and confirmed providing for the diversion or closure of Public Rights of Way, usually from the District Council. iv) Licences for structures over existing public highway. v) Grants of Easement for Highway Drains from Landowners which should be sought at an early stage. - 5 - 1.6 Initial Consultation Developers are strongly advised to consult with the Department of Environmental Services at the earliest stage as to the details of layout, drainage and construction. In order to establish initial contact, either write to the Director of Environmental Services or telephone the Development Control Group on 01225 713443. Developers or their legal advisors may also wish to have preliminary consultations with the Legal Section of the County Secretary and Solicitor, 01225 713073 as to the form of Section 38 Agreement, approved bondsmen and the terms of any easements required. - 6 - 2 PROCEDURE FOR ENTERING INTO A SECTION 38 AGREEMENT 2.1 Compliance with the Specification The developer is required to provide design drawings and other information relating to the proposed highway works that should comply with the attached Specification. 2.2 Drawing Requirements A formal written application for entering into a Section 38 Agreement should be made to the Director of Environmental Services accompanied by two copies of each of the following drawings/documents:- Scale (I) Site Plan showing location 1/1250 or 1/2500 (ii) Layout of roads, footpaths and drainage showing full 1/500 or 1/200 details including dimensions, contours, driveway gradients, gullies, watercourses, buildings, visibility splays, setting-out information and street lighting (iii) Longitudinal sections of the carriageway and Horiz. 1/500 or 1/200 independent footpaths showing existing ground levels Vert. 1/50 or 1/20 and proposed centre line and channel levels (iv) Longitudinal sections of any highway drainage Horiz. 1/500 showing existing and proposed ground levels, invert Vert. 1/50 levels, gradients, pipe classifications and bedding details (v) Cross sections at such intervals considered necessary 1/50 or 1/100 to fully interpret the scheme (vi) Construction details showing construction depths, 1/10 or 1/20 proposed materials and any other relevant details (vii) Details of any structures, including design calculations, As appropriate which appertain to the highway works (viii) Drainage calculations for any highway drainage and, if appropriate, pipe strength structural calculations. (ix) Soils investigation report (if available) (x) Details of any rights of way affected by the proposed 1/1250 or 1/2500 development, including any proposals for closure or diversion Unless otherwise agreed, all levels shall be to Ordnance Datum. In addition to the above drawing requirements, 2 additional copies of the 1/500 Layout Plan should be provided in order that soils testing may be arranged. (See 2.3 overleaf). - 7 - Finally, a further copy of the 1/500 layout plan should be provided indicating:- i) The land in the ownership of the developer edged red. ii) The area being offered for adoption coloured pink. iii) Any areas of existing highway affected coloured yellow. iv) Highway drainage to be adopted coloured dark blue. v) Any drainage easements coloured pale blue. vi) Any phasing requirements. 2.3 Soils Testing 2.3.1 General At the same time as making the above submission and, if not previously arranged by themselves, the developer or their agents should confirm their agreement to paying all costs in respect of soils testing by a Wiltshire County Council’s approved laboratory. This is necessary primarily in order to establish C.B.R. values for the sub-soil, which will ascertain the required construction depth. Any special requirements due to abnormal ground conditions will also be established. The developer will be informed of the required sub-base thickness (and capping layer requirement if appropriate) and will receive a copy of the laboratory report. If C.B.R. values are not available for the proposed design, a value of less than 2% must be assumed. 2.3.2 Road Design The designer shall assess the CBR of the subgrade for: i) Suitability for construction ii) Construction CBR value iii) Equilibrium CBR value The construction CBR shall be assessed by either in-situ testing at the time of construction or in the case of embankments by laboratory testing of samples recompacted at moisture contents and dry densities which reflect the likely conditions on site. The assessment of the long-term CBR at equilibrium moisture content for cohesive soils may be found by using LR 1132 “The Structural Design of Bituminous Roads” by W D Powell, J F Potter, H C Mayhew, and M E Nunn TRRL – HMSO.