DMRB Assessment Process

Transport Scotland uses a three-stage assessment process to determine the preferred route option for trunk road improvement projects. This is based on the Design Manual for Roads and Bridges (DMRB). This consists of:

• DMRB Stage 1 – Improvement Strategy Assessment – Stage complete
• DMRB Stage 2 – Route Option Assessment – Stage in progress
• DMRB Stage 3 – Development and assessment of the preferred route option
• Statutory Process – Publication of draft Road Orders, Compulsory Purchase Order (CPO), Environmental Impact Assessment Report, and Public Local Inquiry (if required)
• Procurement – Tender process to appoint works contractor
• Construction

This process involves:

• Survey work (including environmental, geotechnical and traffic surveys)
• Consultations with specific bodies
• Development and assessment of route options to consider engineering, environment, traffic, safety and economic factors
• Public engagement and stakeholder consultation

At DMRB Stage 1, we developed and assessed broad improvement strategies. To inform the assessment, we carried out broad engineering, environmental, traffic and economic assessments of the potential impacts of each improvement strategy. The DMRB Stage 1 Assessment Report containing the findings from this work was published in September 2025.

DMRB Stage 2 is currently ongoing and involves the development and assessment of route options within the broadly defined improvement strategies taken forward from DMRB Stage 1. This includes more detailed engineering, environmental, traffic and economic assessments of the potential impacts and opportunities associated with each route option.

We will use the feedback we receive to help inform, develop, refine and assess route options at DMRB Stage 2. We will continue to engage with landowners, members of the public, and other stakeholders as we continue to develop the route options and work towards identifying the preferred route option.