Buyer	National Highways — not a council we hold
Supplier	WSP UK Limited

National Highways (the Client) is seeking the provision of services to undertake research into Diverging Diamond Interchanges (DDI). STAGE 1 SCOPE: Overall, the aims of this task are to: 1. Measure the safety performance of DDIs to clearly understand how or if they are safer than existing junction types; 2. Examine potential risks and hazards such as Wrong Way Driving; 3. Review international standards and determine relevance to UK; and 4. Review the DMRB to understand how requirements and advice would need to change to encompass Diverging Diamond Interchanges. The award of this work package is initially for Stage 1 only (see background). Subject to further funding, a STAGE 2 FEASIBILITY task would be undertaken in the next financial year: - Identify a location where the layout can be retrofitted and modelled to existing infrastructure such as at an existing dumbbell roundabout at a grade separated junction and then examine scalability across the network; - Investigate how any new risks such as Wrong Way Driving or failure of traffic signals can be reduced or removed; - Measure the environmental and economic benefits such as land take reduction and carbon saving; and - Provide recommendations for requirements, advice and drawings to update the DMRB and update the standards CD 122 and CD 123. This is anticipated to be a report and not an update to the standards in case the findings do not support changing the DMRB.

Runs	25 Jun 2025 to 31 Mar 2026
OCID	ocds-b5fd17-b4c136e0-b340-4d19-a00b-ee1b2e94737e
Notice	Read it on Contracts Finder

Figures are as published An award value in OCDS may be a framework ceiling rather than a sum anyone expects to spend, so a large figure here is not evidence of a large purchase.