Overview
The detailed business case (DBC) confirms an activity that comes from the detailed programme (previously called ‘package’) of activities and confirms the overall assessment profile. It includes a more detailed reporting of economic, financial and commercial aspects of the activity built upon the indicative business case.
The DBC should be completed before commencing the detailed implementation (including detailed design, property acquisition, consenting or construction) of the activities. It is recognised that whilst activity specific guidance may be used to inform the options considered as part of the DBC, designs should not be progressed past this level until the DBC is complete and decision makers make their informed choice of the option(s) to be taken forward to implementation.
Appraisal of alternatives and options and production of a DBC should precede any commitments to the project. This ensures the proper consideration of the transport issues relative to the proposals being developed and presentation of these aspects in a clear manner.
Detailed assessment of the options which have been taken forward from the indicative business case with specific consideration given to:
- Outcome objectives: a detailed appraisal of options against the transport outcomes using quantitative techniques and analysis.
- Assessment of impacts: a detailed appraisal of the impact of options using qualitative and quantitative techniques and analysis.
- Cost to government: a detailed analysis of the total public sector cost of options, including investment costs, operating and maintenance costs.
- Risk and uncertainty: a detailed analysis of the risk and uncertainty associated with each option.
See the Detailed business case overview for more information.
Key steps
- Reconfirm strategic fit and investment assessments.
- Reconfirm the project/activity team.
- Procure professional services.
- Develop the option(s).
- Understand context, problems, opportunities and constraints.
- Focus on the key risks. For example, if environmental factors are the biggest risk, more effort should be expended on considering those factors.
- Develop a scheme estimate.
- Obtain independent peer reviews as required.
- Engage with stakeholders and the public.
- Consider land and property requirements.
- Consider the strategic, economic, financial, management and commercial aspects of the business case. For further guidance, view the Detailed business case template .
- Produce the detailed business case using the template.
- Obtain endorsements as required and approvals according to delegations, review with stakeholders.
- Approved.
- Progress to the next phase(s), pre-implementation.
Quality assurance and approvals
Records of quality assurance and approvals should be undertaken in accordance with the Highways and Network Operations project assurance and approvals process .
There are also check in points to keep in mind through a DBC or combined IBC/DBC. One check point is mentioned with an investment quality assurance (IQA) based on 12 of the 16 investment questions. The rationale for the check in and IQA is to provide assurance the business case is on the right track, the quality is high, and there is wider organisational buy in to the short listed options prior to public consultation.
Technical requirements
For each phase of the business case process there are technical requirements that may be relevant to your project that will need to be considered and included in addition to general guidance and templates. Aligned to the business case philosophy, suppliers are required to meet more technical requirements as an activity progresses through the business case phases.
Outlined below are the technical requirements for completing the detailed business case, by subject matter.
Suppliers are required to comply with these requirements except where varied within the scope of a contract.
For further information or advice, contact the relevant team.
| Subject matter | Technical requirements | Information | Contact |
| Asset management | SM018 whole of life costs - NPV, IAMP, LAMPs | Asset Management team | |
| Community and stakeholder engagement | Update community engagement plan based on outcomes of the IBC | Community and stakeholder engagement | Environment team |
| Prepare consultation report on engagement process, outcomes. This report will be used to support applications for statutory approvals | |||
| Economics | Economic viability tables 8.1 and 8.2 of DBC template - detailed benefits and BCR of options | Economic evaluation manual | Outcome Planning team |
| Outcome delivery - detailed benefits by benefit type | |||
| Risk analysis table 8.3 of the DBC template - sensitivity testing | |||
| Environment and social responsibility | Update Environmental and Social Responsibility Screen | Refer completed screen | Environment team |
| Prepare preliminary technical assessments (if required) | Impact assessment guides and the consenting strategy for the project determine level of detail required for environmental or social technical assessments | ||
| Prepare consenting strategy | Consenting strategy and approvals pathway guide and consenting strategy template | ||
Ensure preliminary design statement incorporates screen results, results of any preliminary technical assessment and consenting strategy including suggested mitigation by:
| State highway environmental plan | ||
| Scope environmental and social technical assessments to support consenting strategy | ESR Standard explanation | ||
| Geotechnical | Preliminary geotechnical appraisal report | Requirements currently detailed in SM030 | Structures team |
| Geotechnical testing and assessment undertaken with results presented in a Geotechnical assessment report (factual report) and interpreted in a Geotechnical interpretative report | |||
| Assumed design parameters for subgrade strength and fill and cut batter slopes presented in Preliminary design philosophy statement | |||
| Pavements | Pavement design required - not at detailed design level | NZ supplement to the 2004 Austroads pavement design guide Austroads Guide to Pavement technology: Part 2, Pavement Structural Design Sections to consider: 3, 5, 6, 7, 8, 10 | Pavements team |
| Property | Acquisition agent to negotiate access to specific parcels of land. Compile due diligence information and update the risk assessment for each. Surplus property is incorporated into the 5 year disposal programme | Property team | |
| Risk | As the project lifecycle transitions through the business case phases the increasing maturity of programme data and clarity of understanding should be reflected in an increasing depth of maturity in the level of risk management data and application of risk management practices | Project risk management | Risk team |
| Road safety | Road safety audit - concept audit | Road safety audit procedures | Safety team |
| Design - review of compliance with guidelines - exception report | |||
| Statutory approvals | Prepare preliminary planning assessment of relevant planning and statutory framework | Environment team | |
| Prepare preliminary technical assessments (as required) | Subject matter impact assessment guides | ||
Evaluate consenting package options and the different decision making pathways Prepare consenting strategy If EPA process preferred, refer to NZTA-EPA relationship protocol Prepare preliminary assessments of alternatives, consultation report and statutory consultation requirements | Consenting strategy guide | ||
| Scope environmental and social technical assessments to support consenting strategy | Impact assessment guides will help prepare scope | ||
| Structures | Preliminary structure options report(s), developed to identify alternative options for bridges and other highway structures (category 1 and 2 structures only), to be included within the Preliminary design philosophy statement | Bridge manual appendix F | Structures team |
| Transport modelling | Economic viability - detailed benefits | Transport model development guidance | Outcome Planning team |
Tools
Forms and templates
| Title | Type | Document | |
| Detailed business case document | Template | Word |
Guidelines
| Title | Download |
| P&I knowledge base develop detailed business case | Website link |
| IBC/DBC check in point |
For further information contact outcomeplanning@nzta.govt.nz .