Safety in Road Tunnels: Analysis of Fire Accident Location inside the Gran Sasso Tunnel in Italy

The aim of this research is to analyze the fire events occurred inside the Gran Sasso unidirectional highway tunnel in Italy. The Gran Sasso tunnel consists of two parallel one-way tubes with a length of about 10100 m. The tunnel, managed by Strada dei Parchi S.p.A., is one of the 14 tunnels belonging to the A24 and A25 motorways subject to the application of the European Directive 2004/54/EC. This Directive requires a Quantitative Risk Analysis (QRA) for tunnels belonging to the Trans-European Road Network and longer than 500 m. This study analyzed the fires and fire principles (which failed to develop into fire) that occurred in the left tube of Gran Sasso tunnel during the period 2007-2020, which consists of an uphill section of about 4500 m followed by a slightly downhill one. These events involved both light and heavy vehicles; their location along the tunnel and the possible causes were considered. Out of the 12 events analyzed (6 fires and 6 fire principles) it was observed that 11 events occurred in the uphill section while only one event occurred in the downhill section. The results of this study can be used for the implementation of risk analyses according to the European Directive but can also represent a useful tool for tunnel managers to evaluate the possible increase in the number and location of fire detection devices and/or fire suppression/control systems.