Modelling project feasibility robustness by use of scenarios

Key words: Evaluation, Scenario, Uncertainty, Multi-Modal Abstract: This paper presents the application of a new scenario based analysis technique which has been developed for transport infrastructure planning. The approach aims at dealing with uncertainty in the planning environment in a more systematic way than is usually the case when applying scenario analysis. Specifically, the developed scenario approach secures a consistent inclusion of actual scenario elements in the quantitative impact modelling and facilitates a transparent project feasibility robustness analysis. The approach has been implemented in a SCENARIO MANAGER as part of an infrastructure planning decision support system which comprises GIS-related impact models embedded in a tool-box applicable to multi-modal transport investment analysis. Following a brief introduction, the next section of the paper outlines a conceptual scenario model which categorises project uncertainties into three main groups: Objective, adaptive and subjective uncertainty. This model illustrates the correlation between the scenario definition and the uncertainty in the planning environment. This scenario approach distinguishes itself from usual single dominant issue scenarios or prognoses as it is based on thematic scenario writing. In the case presented, four scenarios are introduced which have been developed in a recent Danish scenario study: (I) the market-oriented society, (II) the locally-oriented society, (III) the supra-national society and (IV) the technological society. Each scenario is then analysed as concerns its impact on a set of relevant project evaluation criteria. The criteria used stem from the on-going EUNET project funded by the European Commission DGVII, within the Strategic Transport part of the Fourth Framework Programme. Section three of the paper demonstrates the application of the systematic scenario analysis technique by means of a case study. The case concerns multi-modal evaluation of the Harbour Tunnel under the Copenhagen harbour. One-third of central Copenhagen is divided from the rest by the harbour. Presently, the harbour has four road bridge crossings and one rail bridge crossing. The investment in question concerns a fifth road tunnel at the entrance of the harbour, which aims at forming a complete high standard road systems around Copenhagen while at the same time reducing the environmental impacts to the medieval town centre. Four different solutions to the inclusion of the new Harbour Tunnel in the road network are examined. The concept of scenario profiling is introduced, which in an operational manner examines the project robustness related to each of the four project alternatives. The scenario profile gives a comprehensive description of the scenario implications for the socio-economic feasibility of each project alternative. Through a systematic, scenario based set of weights, the overall project robustness is determined. The final section five presents conclusions and recommendations. It is stated that the scenario approach presented is a valuable aid in assisting decision making on transport investment planning. The area for future research into the further integration of model uncertainty with scenario based robustness evaluations, is outlined.