Design Manual for Roads and Bridges (DMRB).
Applying the Design Manual for Roads and Bridges where it is needed: trunk roads, higher-speed routes and the audit and assessment standards councils borrow from it.
Also known as: DMRB, Design Manual for Roads and Bridges, CD 109, CD 123, GG 119, GG 142
What’s included.
DMRB is the design standard for motorways and trunk roads in the UK. Many local authorities also use parts of it on higher-speed roads, and its Road Safety Audit standard (GG 119) and WCHAR standard (GG 142) are widely applied on local schemes.
- Geometric design to CD 109 and CD 123
- Stopping sight distance on higher-speed roads
- Road Safety Audit to GG 119
- WCHAR to GG 142
- Departures from standard
- When MfS is more appropriate
Straightforward, proportionate, agreed early.
Use it where it fits
DMRB on trunk and high-speed roads; MfS where the street context calls for it.
Know the departures
Where a standard cannot be met, a departure can sometimes be agreed with evidence.
Current standards
Work to the current DMRB documents, not superseded ones.
Questions we get asked
Is DMRB mandatory on local roads?
No. It is mandatory on the trunk road network. Local authorities choose whether to use it on their roads.
What is a departure from standard?
An agreed variation from a DMRB requirement, justified with evidence and approved by the overseeing organisation.
Which DMRB documents cover junctions?
CD 123 covers at-grade priority and signal-controlled junctions, and CD 116 covers roundabouts.
Often needed alongside.
Last reviewed October 2026 by Ripple Development Planning. Policy and guidance change; for advice on a specific site, send us the details.
From our insights.
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