Design standards

Trunk roads must be designed in accordance with the most up-to-date standards, and take into account any variants specific to Scotland.

The Design Manual for Roads and Bridges (DMRB) provides a comprehensive system which accommodates current design standards, advice notes and other published documents relating to the design, assessment and operation of trunk roads.

The DMRB was introduced in 1992 in England and Wales, and subsequently in Scotland and Northern Ireland.

It was originally developed from a series of guidance documents previously published by the overseeing organisations of England, Scotland, Wales and Northern Ireland. The documents were then brought together into a consistent format of guidance documentation.

Transport Scotland is responsible for collaborating with the other UK overseeing authorities application of the design standards, and in the development of new standards.

The Design Manual for Roads and Bridges

The Design Manual for Roads and Bridges sets a standard of good practice that has been developed principally for trunk roads. It may also be applicable in part to other roads with similar characteristics. Where it is used for local road schemes, it is for the local roads authority to decide on the extent to which the documents in the manual are appropriate in any particular situation.

The DMRB is divided up into 15 Volumes, as follows:

• Volume 0 - Introduction and General Requirements
• Volume 1 - Highway Structures: Approval Procedures and General Design
• Volume 2 - Highway Structures: Design (Substructures & Special Substructures), Materials
• Volume 3 - Highway Structures: Inspection & Maintenance
• Volume 4 - Geotechnics & Drainage
• Volume 5 - Assessment & Preparation of Road Schemes
• Volume 6 - Road Geometry
• Volume 7 - Pavement Design & Maintenance
• Volume 8 - Traffic Signs & Lighting
• Volume 9 - Traffic Control & Communications
• Volume 10 - Environmental Design
• Volume 11 - Environmental Assessment
• Volume 12 - Traffic Appraisal of Road Schemes
• Volume 13 - Economic Assessment of Road Schemes
• Volume 14 - Economic Assessment of Road Maintenance
• Volume 15 - Economic Assessment of Road Schemes in Scotland

Manual of Contract Documents for Highway Works

The Manual of Contract Documents for Highway Works (MCHW) is a complementary manual to the DMRB. It contains:

• documents relating to contract document compilation, including specifications
• notes for guidance and methods of measurement for highway works and specialist activities
• Standards and Advice Notes covering various procurement issues.

The MCHW also contains the Specification for Highway Works and the Highway Construction Details. These documents are incorporated directly into contracts by reference.

Interim Amendments

Transport Scotland issues Interim Amendments (IAs). These contain specific guidance, applicable in connection with works on motorways and trunk roads in Scotland.

Whilst all IAs must be read in conjunction with the DMRB and the MCHW, and may incorporate amendments or additions to documents in these manuals, they are not part of either documents.

More detail on the Design Manual for Roads and Bridges and the Manual of Contract Documents for Highway Works is available on the Department for Transport website.

See also Access For All and the New Road Surface Specification (TS2010).