Probabilistic modeling of vulnerability of road infrastructures to floods

Factors which contribute to the vulnerability of physical elements such as road infrastructures to a natural hazard such as a flood event are pervaded by uncertainty due to the complexity of the hazard, of the vulnerable infrastructure and of their physical interaction. In the context of risk management efforts, it is conceptually correct to explicitly address this uncertainty and to parameterize the criticality of the vulnerable element and, consequently, an explicit target degree of conservatism and reliability in risk assessment and mitigation strategies. This paper illustrates the results of the probabilistic characterization of the vulnerability of road infrastructures to flood events for two areas in South-Eastern Norway. Flood intensity and road vulnerability serve as inputs to an analytical model, which expresses the latter as a function of the former with respect to a user-set level of probability of exceedance. Deterministic and probabilistic vulnerability estimates are compared quantitatively, and the results are assessed and analyzed critically.