Road development and improvement schemes: highway design standards

This resource provides an overview of the design standards an engineer should use for road development and improvement schemes.

Road widening scheme for the A453
Road widening scheme for the A453

This information is primarily based upon highway engineering practice in England, but there are lessons and resources used in this overview, which could be applied to the rest of the UK and internationally

Effective highway design and engineering

There are many factors, which an engineer must consider when designing a new highway. Good and effective highway design is based upon an accurate knowledge of the properties of the materials used and the design loadings, using well-researched engineering principles and developed and validated computer programs. It must also take account of the interaction with the existing ground and the environment.

ICE’s Manual of Highway Design & Management (2011) provide descriptions of and notes for guidance to the referenced established design procedures and methods used in the UK and in some cases provide enough information for straightforward designs to be produced for that topic.

Chapters 31-34 of this ICE Manual include essential guidance on:

  • Chapter 31 - Highway design principles and practice: an introduction
  • Chapter 32 - Site investigation and foundation design
  • Chapter 33 - Geometric design
  • Chapter 34 - Drainage design

Highway design standards

All highway design for the Highways England must be carried out by consultants with BS EN ISO9001: Quality Management Systems. Requirements (British Standards Institution, 2008) third-party certification satisfying the requirements of their guidance document GD 02/08 Quality management systems for highway design published in Design manual for roads and bridges (DMRB). This explains how the general quality assessment principles are relevant to highway design, the management responsibility and which quality plans and records should be kept. It also explains the competency requirements for the design team in terms of skills, knowledge and ability to understand requirements.

Specification for Highway Works

A design engineer should be familiar with the contents of the Design Manual for Roads and Bridges (DMRB) and the Manual of contract documents for Highway Work.

The Specification for Highway Works is published as Volume 1 of the Manual of Contract Documents for Highway Works and contains the requirements and approvals procedures for work, goods or materials used in the construction, improvement or maintenance of the Trunk Road network. This an essential reference tool for agents, authorities, consultants and organisations who are engaged in the design, assessment, maintenance and management of road and bridge design.

Concept design and feasibility

In preparing a concept design for a major development, the Highway Engineer would address the practicalities of cost effective access for all modes of travel, assessment of the suitability of the existing infrastructure, the parking and servicing arrangements and the detailed design of on and off-site civil engineering works.

Feasibility studies involve both a desktop and a site visit, address the key fundamentals of access, and access constraints. Investigations will also take place as to the current lawful use of the site and its present potential for generating traffic.

Preliminary design

The purpose of the preliminary design is to enable a decision to be taken on where the road should be located within the preferred route envelope. This design will include topographical, environmental and geographical surveys.

Final design

The purpose of the final design is to:

  • produce further detailed topographical, geological and geotechnical surveys;
  • produce detailed design of bridges/structures, drainage, earthworks and pavement;
  • Consider health & safety and factor this into the detailed design. The CDM Regulations 2015 can be downloaded from the Health & Safety Executive website.

Closing remarks and recommended resources

Highway design is an a critical component in the creation of an effective road network, and civil engineers are vital to delivering the essential infrastructure which connects our towns and cities.

ICE Books

The intention of this information is to give a general overview of Highway Design and direct engineers to further guidance and resources to aide them in preparing highway design documents. ICE’s Manual of Highway Design & Management (2011) is an excellent resource for engineers of all levels, and is a highly recommended resource.

Equally useful is ICE’s Principles of Pavement Engineering (2014) and for the undergraduate engineer, Highways: the location, design, construction and maintenance of road pavements (2015) is an extremely useful reference tool.

ICE Training

ICE Training provides a range of courses to help you improve your understanding and knowledge of highways engineering. Courses include:

View more training from ICE Training

External resources

Highways England produces standards and documentation relating to the design, construction and maintenance of highways. Documents are available free online, including:

  • The Design Manual for Roads and Bridges (DMRB) contains information about current standards, advice notes and other published documents relating to the design, assessment and operation of trunk roads, including motorways. The DMRB has been prepared for trunk roads and motorways. The basis of use of these documents by local highways authorities is given in the DMRB GD 1/08. Check with your local highway authority for their policy on this matter The DMRB was introduced in 1992 in England and Wales, and following that in Scotland and Northern Ireland. Some standards and specifications have annexes specific to each devolved administration. You should contact the relevant devolved authority directly for guidance.
  • Well Maintained Highways - Code of Practice Published in July 2005, it provides local authorities with guidance on highways management in an ever changing environment, creating a strong foundation for a positive and lasting maintenance policy. Adoption of the recommendations in this code will help the delivery of Best Value services.
  • The Manual of Contract Documents for Highway Works contains the primary documents required for the preparation of contracts for trunk road works. It consists of several parts, including the administrative procedures for its use, the specification for highway works and the corresponding method measurements.
  • Interim Advice Notes (IANs) issued by Highways England contain specific guidance, which should only be used in connection with works on motorways and trunk roads in England, subject to any specific implementation instructions contained within an IAN. IANs are not part of the DMRB and the MCHW but must be read in conjunction. They may incorporate amendments or additions to documents in these manuals.
  • Eurocodes - As a public body, Highways England expresses its requirements for the design and modification of existing structures (including geotechnical works) in terms of Eurocodes. Highways England’s technical experts were involved in the drafting of the Eurocodes and the National Annexes.
  • The Network Management Manual (NMM) provides mandatory requirements, guidance and advice for the management of maintenance of the trunk road network.
  • The performance requirements for routine and winter service activities on the trunk road network are included in the Routine and Winter Service Code.
  • The Traffic Management and Maintenance Manual, published January 2013, sets out requirements for the management and maintenance of traffic technology systems.

Further information related to standards for highways is also available on the Standards for Highways online resource webpage.