This thesis aims to provide a comprehensive and in-depth overview of road tunnel safety by analyzing major historical accidents, the regulatory responses that followed, and the technical solutions necessary to reduce risk levels and mitigate the consequences of potential critical events. Following a brief review of major historical accidents in recent years—such as the fires in the Mont Blanc Tunnel, the Tauern Tunnel, and the Gotthard Tunnel between 1999 and 2001—the focus shifts to the main European regulations enacted to enhance road tunnel safety. Particular attention is given to EU Directive 2004/54/EC, introduced by the European Commission in 2004 in response to these tragic events.