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DMRB: General Principles and Scheme Governance GD 300 Version 3.0.0 Enhanced all-purpose dual carriageways. Version 3.0.0

Publication Year

2026

Document Status

Current

Abstract

Details design requirements and advice for enhanced all-purpose dual carriageways.

Document History

General Principles and Scheme Governance. Design. Supersedes GD 300 Revision 2 Requirements for new and upgraded all‐purpose trunk roads (expressways). Revision 2 (HA, 2020). Version 0 dated May 2019. Version 1 dated March 2020 - updates England NAA. Version 2 dated April 2020 - minor administrative changes to England NAA. Version 2.1.0 dated September 2024. Version 3.0.0 dated June 2026.

Publisher Information

National Highways

National Highways is an executive non-departmental public body, sponsored by the Department for Transport. It has responsibility for operating, maintaining and improving motorways and major A roads in England. Formerly known as Highways England, between 2015-2021 and Highways Agency, between 1994-2015.