Parallel Paths of Equal Reliability Assessed using Multi-Criteria Selection for Identifying Priority Expendature
Thesis DisciplineTransportation Engineering
Degree GrantorUniversity of Canterbury
Degree NameMasters of Engineering Transportation
This research project identifies some factors for the justification in having parallel network links of similar reliability. There are two key questions requiring consideration: 1) When is it optimal to have or create two parallel paths of equal or similar reliability? 2) How could a multi-criteria selection method be implemented for assigning expenditure?
Asset and project management always have financial constraints and this requires a constant balancing of funds to priorities. Many methods are available to address these needs but two of the most common tools are risk assessment and economic evaluations. In principal both are well utilised and generally respected in the engineering community; when it compares parallel systems both tend to favour a single priority link, a single option. Practical conception also tends to support this concept as the expenditure strengthens one link well above the alternative.
The example used to demonstrate the point that there is potential for parallel paths of equal or similar reliability is the Wellington link from near the airport (Troy Street) up the coast to Paekakariri. Both the local and highway options have various benefits of ease of travel to shopping facilities. Investigating this section provides several combinations from parallel highways to highway and local roads, so will have differing management criteria and associated land use.
Generalised techniques are to be applied to the network. Risk is addressed as a reliability index figure that is preset to provide a consistent parameter (equal reliability) for each link investigated. Consequences are assessed with multi-criteria selection focusing on local benefits and shortcomings. Several models are used to build an understanding on how each consequence factor impacts on the overall model and to identify consequences of such a process.
Economics are briefly discussed as the engineering community and funding is almost attributed to financial constraints. No specific analytical assessment has been completed.
General results indicate there are supporting arguments to undertake a multi-selection criteria assessment while comparing parallel networks. Situations do occur when there is benefit for parallel networks of equal or similar reliability and therefore equal funding to both can be supported.