Simulation based characterization of critical infrastructure system resilience : application to a snowfall scenario

Nowadays, due to technological developments, society is becoming more dependant of a large variety of infrastructures which are highly interconnected and, unfortunately, continuously exposed to a wide range of risks. For that reason, protection and resilience becomes an important issue when dealing with Critical Infrastructures. It is of high importance that in the case of a threat affecting one or more infrastructures, like the snowfall of December 2009, private and public operators of the entire transportation system are aware and committed with the existing procedures –and the continuous development of them through information sharing processes- to guarantee safety and service recovery of their own and other critical infrastructures. The direct impact of the mentioned snow storm on various types of infrastructures is modeled using the Functional Model developed by Trucco et al. (2010), taking into account the countermeasures and processes for the restoration of infrastructure capabilities that were adopted by operators to minimize the inoperability of the involved systems as well as proposed actions to improve their performance. Two main scenarios are modeled: an elementary failure scenario considering the failure of a single node (simulating three different recovery processes for each) and analyzing how its disruption affects the entire system to obtain a list of the most critical nodes in terms of total disservice and agility; a complex failure scenario considering the failure of several nodes due to a single threat, focusing the analysis on the critical nodes obtained from the elementary scenario and modifying their response time producing an overall improvement of 14% (340,000 users).