Decision Support Process

The Decision Support Process is the decision-making half of TPRAF, the Transport Performance and Risk Analysis Framework. It is built from six key process flows that together describe a complete decision cycle.

A cycle, not a sequence

The six flows run from understanding the current system, through to learning from outcomes, and then feeding that learning back into future decisions. The last stage is not an endpoint. It is what makes the next pass through the process better informed than the last.

The six process flows

#	Process flow	What this stage establishes
1	Asset and network evaluation	How the system currently functions: its condition, capacity and constraints
2	Problem framing and scope	What needs to be adapted and why, and the boundaries of the question
3	Risk reduction analysis	Which options are worth carrying forward, filtered by risk and resilience evidence
4	Detailed option assessment	How the shortlisted options actually compare, on cost and on wider criteria
5	Portfolio optimisation	How interventions combine and sequence when taken together rather than one at a time
6	Outcome assessment	Whether the intervention worked, and what that teaches the next decision

Each is documented in full in Technical processes.

What the cycle is designed to deliver

These stages are intended to provide a holistic, systems-based approach to the whole-life management of complex infrastructure. Three words in that phrase are doing real work:

Term	What it rules out
Holistic	Judging an intervention on one dimension, such as cost alone
Systems-based	Treating an asset as if it were independent of the network around it
Whole-life	Optimising for the build, and letting operation and maintenance fall where they may

Within that, the process sets out to optimise three things: asset performance, maintenance, and lifecycle management.

It works at two levels at once

This is a distinguishing feature of the DSP rather than an incidental detail. The same process operates at:

the network level, where the question is how the system as a whole performs
the individual asset level, where the question is what to do about one structure

Running both together is what allows a decision about a single asset to be judged by its effect on the wider network, which is precisely the link that siloed asset management tends to lose. See Organisational processes for why that matters in practice.

The seven modules

The process flows describe what happens. The modules supply what it runs on: the structured data, models and relationships needed to execute each stage.

Their shared purpose is evaluating low-carbon, sustainable and resilient adaptation decisions, and the approaches that achieve optimal outcomes.

Module	Documented in
Asset Registry	Asset Registry
Asset Performance	Asset Performance
System Interdependencies	System Interdependencies
Resilience	Resilience
Sustainability	Sustainability
Risk Assessment	Risk Assessment
Risk Mitigation	Risk Mitigation

The modules are still in development

The source handbook says the seven modules "are being developed", in the present tense. This handbook documents them as designed, not as finished and deployed software. Treat module descriptions as the specification rather than a user manual.

What this chapter covers

Page	What you will find
Purpose	The problem in current practice the DSP responds to, and what it provides instead
Use Cases	Illustrative cases for different decision types
Scope	The range of decisions the process applies to
Users	Who operates the process and who consumes its outputs
Organisational Processes	How the DSP maps onto how Network Rail and National Highways already work

A missing figure

The source handbook refers to Figure 2.1, "Overview of DSP embedded within TPRAF", and its caption is present. The image itself was never inserted into the document, so it cannot be reproduced here.