The Design Manual for Roads and Bridges (DMRB) consists of a suite of documents which contain the requirements and guidance for all work to manage the strategic road network in the UK. In 2019 a comprehensive review was needed to ensure consistency across the guidance.
Working closely with Highways England, two of the documents within the DMRB were: LA 113 Road Drainage and the Water Environment and CD 532 Vegetated Drainage Systems for Highway Runoff.
LA 113 Road Drainage and the Water Environment provides assessment guidance on the impacts that roads can have on the water environment. Our involvement with the project began over 20 years ago with the development of a method used to assess the risk that spillages could pollute adjacent water bodies, which remains in use to date. The latest revision, published in 2019, includes guidance we developed for assessing the risk of flooding, both to and from the road, and how it can be managed.
CD 532 Vegetated Drainage Systems for Highway Runoff contains the design requirements for sustainable drainage systems suitable for use on strategic roads in the UK. We have assisted the development of the document since it was first published in 2001 and have been solely responsible for assisting in its subsequent revisions, the latest of which was published in March 2020.
The update to these documents has brought them up to date, and made them more concise and easier to use for all those involved in the management of the UK’s strategic road network.