A methodology to analyse road network vulnerability to shocks: Some evidence from two metropolitan areas in the south of Italy

Network vulnerability plays a critical role in the functioning of metropolitan areas, where transportation systems are integral to sustaining economic activities and facilitating daily commuting. However, these networks are highly susceptible to disruptions, which can result from accidents, infrastructure breakdowns, or natural disasters. This study analyses the impacts on mobility caused by a traffic disruption in metropolitan areas; the case study are the cities of Bari and Naples. An accessibility indicator and a traffic flow and travel time-based indicator (link importance index) have been used to perform a vulnerability analysis of the road networks. Using Visum software, various traffic disruptions have been simulated, and vulnerability maps have been subsequently developed. Results show that in both case studies the worst-case scenario occurs with the closure of a segment of the arterial ring roads of the two cities. The approach shows to be a valid aid to assist local administrators and transportation agencies in developing effective traffic management strategies and emergency plans.