Analysis by project or by section
Overview
Section titled “Overview”Analysis by Project and Analysis by Section are two distinct methods for evaluating road investment options. The choice between them depends on whether the goal is to optimise evaluate a package of works across multiple segments as a single investment, or to evaluate individual road segments.
Analysis by Project
Section titled “Analysis by Project”This method treats multiple road sections as a combined “package” or project. It is the standard mode for Project Analysis applications, allowing for the evaluation of large-scale schemes that span across different segments.
- Unit of Analysis: The project alternative, which represents the sections as a group.
- Alternatives: Each project alternative defines a specific set of work standards for every section in the group. For example, Project Alternative 1 might apply “Maintenance Standard X” to three different sections, while Project Alternative 2 applies “Standard Y” to those same three sections.
- Economic Indicators: Annual costs and benefits are first summed across all sections within a project alternative to create yearly totals for the whole group. Economic indicators (like NPV) are then calculated for the entire project alternative by comparing it against a designated project base case.
- Key Capabilities: This is the only mode that supports new sections (such as a bypass) and diverted traffic (traffic moving from existing roads to a new link).
Analysis by Section
Section titled “Analysis by Section”This method evaluates each road section individually. It is typically used in programme or strategy analysis to determine the best engineering and economic alternative for every specific segment of the network.
- Unit of Analysis: The individual road section.
- Alternatives: Users define several mutually exclusive alternatives for each section (e.g., three different maintenance strategies for Section A). One alternative is designated as the base case.
- Economic Indicators: Parameters such as Net Present Value (NPV), Internal Rate of Return (IRR), and Benefit-Cost Ratio (BCR) are calculated for each specific section alternative.
- Limitations: This mode does not support the analysis of new road sections or diverted traffic.
Summary Comparison of Evaluation Methods
Section titled “Summary Comparison of Evaluation Methods”| Feature | Analysis by Project | Analysis by Section |
|---|---|---|
| Basic Unit | Group of sections (package) | Individual road section |
| Economic Results | Indicators per project alternative | Indicators per section alternative |
| New Sections | Supported | Not supported |
| Diverted Traffic | Supported | Not supported |
| Typical Usage | Detailed project appraisal | Programme/Strategy prioritisation |