Ensuring a Resilient Road Network in the Western Balkans with Deeply Uncertain Natural Hazards

The strategic road network in the Western Balkans, like many infrastructure systems and networks in numerous developed and developing countries, faces the critical challenge of maintaining network connectivity while ensuring resilience in the presence of natural hazards. This talk will introduce the World Bank funded DIVERSION project and decision support tool which enables users to identify road sections that generate the largest risk to the transportation network and prioritize infrastructure investment, subject to a budget constraint, for reducing overall risk. The tool is informed from the Western Balkans VISUM transportation network model and considers a range of frequent and infrequent natural hazards, whose return periods are regarded as deeply uncertain. Sorting algorithms identify those links in the network that generate high risk over a wide range of uncertainty. The analysis employs economic metrics that include estimates of the financial costs of repair, changes in user costs as a result of disruption, and changes in accessibility which, in conjunction with the duration of disruption, should be correlated with larger-scale economic disruption. Risk is measured with several multi-objective criteria, and the decision support tool allows users to explore how different criteria affect the risk rankings. The tool also uses robust optimization algorithms to identify risk-reducing investment options robust over a wide range of deep uncertainty regarding hazard return period and response option cost. The World Bank, for which this tool was developed, plans to use the study and tool to work with its local partners to allocate transportation investment across the Balkans.