Guidance on the development of Business Cases - March 2016


Both road and rail currently have their own procedures for taking projects from inception to implementation; these are the Design Manual for Roads and Bridges (DMRB), and Guide to Railway Investment Projects (GRIP) respectively. Further detail is provided in Table 1 below.

Table 1- Road (DMRB) and Rail (GRIP)
Road – DMRB Rail – GRIP (Network Rail process)
The DMRB procedures require a detailed assessment of schemes, covering their economic, environmental, and safety impacts. DMRB also contains detailed guidance regarding management and related contractual issues.

The stages of DMRB are:
  • Stage 1: Preliminary Assessment
  • Stage 2: Route Option Assessment
  • Stage 3: Scheme Assessment
Where DMRB is lacking is concerning the means of scheme procurement. Procurement options are generally analysed in accordance with Scottish Government Financial Partnerships Unit Value for Money Guidance in parallel to the DMRB process.

It is also worth noting that the STAG Integration and Accessibility and Social Inclusion criteria are not specifically addressed.

With the exception of ongoing maintenance issues, road schemes generally do not have the financial or commercial implications of rail schemes and the DMRB/VfM process generally covers requirements
The GRIP process is very much focussed on identifying procurement and contracting issues throughout. GRIP was designed to take a project from inception to post-delivery, and so covers all the same elements of the business case process. The stages of GRIP are:
  • Stage 1: Output definition
  • Stage 2: Pre-feasibility
  • Stage 3: Option selection
  • Stage 4: Single option selection
  • Stage 5: Detailed design
  • Stage 6: Construction test and commission
  • Stage 7: Scheme hand back
  • Stage 8: Project close out
However, a key distinction of the GRIP process is that the rationale for intervention is taken as given and is not, generally, revisited during the process. This has prompted the use of a Design Development Appraisal which is in effect the analysis of a single option under the STAG framework in order to check the rationale for intervention remains as the project is subjected to detailed design.

Furthermore, Table 2 below illustrates how each stage of DMRB/GRIP aligns with the Business Case process:

Table 2 – DMRB and GRIP within the Business Case Process
DMRB Business Case GRIP
Stage 1 - Preliminary Assessment Strategic Business Case
Stage 1 - Output Definition
Stage 2 - Pre-feasibility
Stage 3a - Option Selection
Stage 2 - Route Option Assessment Stage 3 - Scheme Assessment Outline Business Case
Stage 3b - Option Selection
Stage 4 - Single Option Development
Final Business Case
Stage 5 - Detailed Design
Stage 6 - Construction Test and Commission
Stage 7 - Scheme Hand Back
Stage 8 - Project Close Out

An IDM decision point should come after each of the SBC, OBC and FBC. Stages 7 and 8 of GRIP take place after the FBC, and will align with the construction and ex-post evaluation stage of a project