The complex system of road infrastructures of a country plays a fundamental role both on the economy and on the development of the territory and on the management of accident scenarios that occur as a result of natural disasters. It is therefore essential to assess the vulnerability of the infrastructural network to natural and man-made risk factors in order to identify any critical issues and plan improvements and upgrades to the infrastructure. This article examines some of the approaches used to assess the vulnerability of complex systems and the methodologies used in the field of road infrastructure. From the analysis of the developed methodologies it emerges that to date there is not a shared definition of road infrastructure vulnerabilities nor a shared methodology of vulnerability assessment. The Quantitative Risk Analysis seems to be the tool that allows to approach in an integrated way the issue of road infrastructure vulnerability, as it allows to relate natural or anthropic events that can occur on the territory and which can interact with the infrastructure, with the characteristics and functional levels in degraded conditions of the infrastructure itself.

The complex system of road infrastructures of a country plays a fundamental role both on the economy and on the development of the territory and on the management of accident scenarios that occur as a result of natural disasters. It is therefore essential to assess the vulnerability of the infrastructural network to natural and man-made risk factors in order to identify any critical issues and plan improvements and upgrades to the infrastructure. This article examines some of the approaches used to assess the vulnerability of complex systems and the methodologies used in the field of road infrastructure. From the analysis of the developed methodologies it emerges that to date there is not a shared definition of road infrastructure vulnerabilities nor a shared methodology of vulnerability assessment. The Quantitative Risk Analysis seems to be the tool that allows to approach in an integrated way the issue of road infrastructure vulnerability, as it allows to relate natural or anthropic events that can occur on the territory and which can interact with the infrastructure, with the characteristics and functional levels in degraded conditions of the infrastructure itself.