A decision model for junction improvement schemes

The selection of appropriate junction improvement schemes is somewhat complex, as most decisions involve multiple objectives, and several decision-makers are subject to stakeholders' review. Usually a subjective engineering judgement process is adopted for selecting new road alignment designs, and so the need arose for a generic decision model to be developed to support engineers and decision-makers in selecting the optimal design solution. This contribution uses multiple-criteria decision-making based on the analytical hierarchy process (AHP) as a means of adopting a formalised and systematic decision framework. The paper also discusses issues relating to inconsistency analyses and model validation. The practical value of the decision framework presented is that it allows the decision-maker to rank choices in the order of their effectiveness in meeting conflicting objectives or priorities.