Italian legislative scheme for tunnel maintenance up to the guidelines for the risk classification, safety evaluation, and monitoring of existing tunnels

Abstract The maintenance and safety assessment of tunnels are fundamental to infrastructure management, requiring a structured and standardized approach to ensure resilience and regulatory compliance. In Italy, the post‐war expansion of the transport network led to the construction of a huge number of tunnels, many of which are now approaching the end of their design life after more than 70 years of service. With over 9000 tunnels spanning approximately 2600 km across the national territory, managing this extensive asset presents a significant challenge, particularly within the framework of a complex and aging road network. To address these challenges, Italian tunnel maintenance regulations have evolved over time, culminating in the 2022 Italian Guidelines for the Risk Classification, Safety Evaluation, and Monitoring of Existing Tunnels . Developed by the Italian Superior Council of Public Works, these guidelines provide a unified methodology to assess risk, ensure safety, and plan maintenance operations at a national scale. They are now a mandatory reference for roadway existing tunnels across the country. This article analyses the structure and implementation of these guidelines, tracing their development from earlier regulatory frameworks, including Circolare 6736/61A1/67and the MIT Manuale di Ispezione . Furthermore, it explores the influence of international best practices, particularly the adoption of key principles from the French regulatory framework, such as the defect cataloguing system. A comparative analysis highlights both the similarities and distinctions between the Italian and French approaches, emphasizing common methodologies in risk assessment and inspection protocols. By examining the integration of these principles within the Italian regulatory framework, this study provides valuable insights into the evolution of tunnel maintenance strategies. The findings serve as a reference for policymakers, engineers, and researchers involved in infrastructure monitoring and safety management, offering a comprehensive overview of Italy's approach to tunnel maintenance in the view of increasing structural and operational challenges.