Transport Scotland ensures that trunk roads are designed with the most up-to-date standards to ensure they:

  • Adhere to the design standards in the Design Manual for Roads and Bridges
  • Are safe and accessible to all users
  • Meet a new standard for road surfacing

Design standards

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.

In addition to DMRB, Transport Scotland publications Cycling by Design and Roads for All: Good Practice Guide for Roads set out guidance which should be used in the design of trunk roads.

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.

In addition to the DMRB, the following documents remain applicable to trunk roads projects in Scotland:

  • TD 37/93 Scheme Assessment Reporting
  • TA 46/97 Traffic Flow Ranges for Use in the Assessment of New Rural Roads
  • TA 79/99 Traffic Capacity of Urban Roads [Incorporating Amendment No.1 dated May 1999]

These documents are available on request from Transport Scotland. These documents are also available on the archive of DMRB standards.

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 regularly updates its design guidance through the issue of Interim Amendments to the design standards.

These amendments are instructions which replace or compliment the design standards, and are applicable only 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).

Transport Scotland regularly updates its design guidance through the issue of Interim Amendments to the design standards. These amendments are instructions which replace or compliment the design standards, and are applicable only in Scotland.

51 - October 2020 - Skidding Resistance

50 - November 2018 - Surface Course Materials for Construction, Scottish National Annex - withdrawn October 2020

49 - November 2018 - The use of Griptester on the Scottish trunk road network

48 - January 2017 - Adoption of IAN 156/16R1 - withdrawn October 2020

47 - August 2016 - TS IA 47/16 - Adoption of IAN 154 - withdrawn October 2020

46 - May 2016 - TS IA 46/16 - Structures Inspector Competencies and Certification

45 - Mar 2014 - TS IA 45 - Management of Abnormal Loads 28 3 14

44 - May 2013 - Simplified Design Method for the Crack, Seat and Overlay Method - Notes for Guidance

43 - Aug 2013 - Strategy for the Repair/Replacement of Joints - withdrawn October 2020

42 - Aug 2013 - Temporary Cover Plates Over Bridge Expansion Joints - withdrawn October 2020

40 - Superseded by HD19/15

39 - Aug 2011 - Use of Eurocodes for the Design of Bridges and Road Related Structures - withdrawn October 2020

38 - May 2011 - Temporary Barrier Decision Tool (TBDT)

37 - Dec 2010 - Design of Single 2+1 single roads - withdrawn October 2020

36 - Dec 2010 - Guidance on structural safety reporting relating to the Scottish Trunk Road Network

35/18 - Nov 2018 - Guidance on the Introduction of Transport Scotland TS 2010 surface course specification

34 - Nov 2010 - Guidance on the use of High Friction Surfacing at Signalised Pedestrian Crossings on single carriageway Trunk Roads - withdrawn October 2020

33 - Oct 2010 - Guidance on the use of various documents relating to General & Principal Inspections for Trunk Road Structures – Withdrawn Oct 2018.

32 - Oct 2010 - Clarification on the deflection of permanent formwork during the construction of trunk road bridges - withdrawn October 2020

31 - Apr 2010 Superseded by IA N°39

30 - Oct 2009 - The Use of Foamed Concrete - withdrawn October 2020

29 - Sep 2015 - Identification of ‘Particularly at Risk’ Supports - withdrawn October 2020

28 - Oct 2010 - Certification of Combined Kerb and Drainage Products - withdrawn October 2020

27 - May 2008 - Implementation of Construction (Design and Management) 2007 and the withdrawal of SD 10/05 and SD 11/05

26 - Feb 2008 - The Anchorage of Reinforcement and Fixings in Hardened Concrete - withdrawn October 2020

25 - Aug 2007 - Assessment and Upgrading of Existing Vehicle Parapets - withdrawn October 2020

24 - Nov 2016 - Guidance on implementing results of research on bridge deck waterproofing

23 - - Revision 3 Jan 2015 - Implementation of BS8500-1:2006 Concrete – Complementary British Standard to BS EN 206-1

22 - Oct 2006 - Implementation of New Reinforcement Standards (BS 4449:2005, BS 4482:2005, BS 4483: 2005 and BS 8666:2005) - withdrawn October 2020

21 - Oct 2006 - Principal and general inspection of sign / signal gantries, and gantries with low handrails or open mesh flooring (BD 63/94 and BA63/94)

20 - March 2018 - Interim Management Strategy for Concrete Half-Joint Deck Structures - withdrawn October 2020

19 - Superseded: See TD 19

18 - Oct 2005 - Manual of Contract Documents for Highway Works (MCHW); the Use of the Saturation Ageing Tensile Stiffness (SATS) Test

17 - Superseded by IA N°23

16 - Aug 2003 - Manual of Contract Documents for Highway Works (MCHW); Sustainability in Construction - the Considerate Constructors Scheme - withdrawn October 2020

15 - Superseded by IA N°19

14 - Mar 2002 - Manual of Contract Documents for Highway Works (MCHW); Aggregates Levy - withdrawn October 2020

13 - Sep 2000 - Manual of Contract Documents for Highway Works (MCHW); Supply of Goods and Services by Local Authorities - withdrawn October 2020

12 - Jan 2000 - Manual of Contract Documents for Highway Works (MCHW); Volume 1: Appendix A: Sector Scheme 14 (for the Production of Asphalt Mixes) - withdrawn October 2020

11 - Dec 1999 - Manual of Contract Documents for Highway Works (MCHW); The Housing Grants, Construction and Regeneration Act 1996 - withdrawn October 2020

1-10 - Interim Amendments 1-10 are no longer applicable

Any enquiries should be directed as listed at the end of the Interim - Amendment.

See an archive of withdrawn Interim Amendments

Departures from Standard - Advice and Procedures Guide

The purpose of the newly refreshed Transport Scotland Departures from Standard Advice and Procedures Guide is to provide interested parties who are seeking Transport Scotland Standards Branch consideration of a Design Manual for Roads and Bridges (DMRB) or Manual of Contract Documents for Highway Works (MCHW) Departure from Standard that affects the Scottish trunk road or motorway network, with the necessary guidance to apply for departures from the standards.

New road surface specification

Transport Scotland introduced a new standard for road surfacing in December 2010 to ensure that our trunk roads are safe and well maintained Image - Testing the skid resistance of the M8 trial section Following issues with the quality and in-service performance of early Stone Mastic Asphalt (SMA) road surfacing, we have been working closely with the roads industry to improve the design and specification of SMA road surfacing.

The decision is based on SMAs proven track record in Germany, where many of the roads remain in excellent condition after more than 20 years. The Scottish specification and guidance is therefore based on the German specifications and experience. Through its operating companies, Transport Scotland safeguards the structural integrity of the trunk road network.

Our ongoing maintenance regime typically includes replacement of the carriageway (reconstruction), the surface (resurfacing) and reinstating the skidding resistance of the surfacing (surface dressing).

Improving the durability of roads offers the following benefits:

  • Reduced delays to road users caused by maintenance
  • Reduced costs of maintenance
  • Improved sustainability of road pavement construction

SMA surfacings can provide the following benefits:

  • Superior durability
  • Lower noise levels
  • Good skid resistance, including early-life
  • High resistance to permanent deformation
  • Decreased life-time costs
  • Thin layer application
  • Excellent ride quality

The surface course, or top layer of the road pavement, incurs the greatest wear and needs to be replaced on a regular basis. The surface course is also the most demanding part of the road in terms of material requirements and properties. A good surface course will provide a smooth and quiet running surface for road users. It is also required to have a high resistance to rutting (the longitudinal channels that develop due to heavy wheel loads) and provide good friction to provide good grip. The surface course also acts as a seal against water infiltrating and harming the lower structural layers of the road.

Archive of withdrawn Interim Amendments