Tunnel Risk Analysis: a Quantitative Evaluation of the Effectiveness of Emergency Teams Inside the A24 and A25 Motorway Tunnels
Borghetti, Fabio
Derudi, Marco
Frassoldati, Alessio
Lai, Igino
Trinchini, Cristian

How to Cite

Borghetti F., Derudi M., Frassoldati A., Lai I., Trinchini C., 2020, Tunnel Risk Analysis: a Quantitative Evaluation of the Effectiveness of Emergency Teams Inside the A24 and A25 Motorway Tunnels, Chemical Engineering Transactions, 82, 277-282.


The European Directive 2004/54/EC - concerning minimum safety requirements for tunnels on the trans-European road network - requires a quantitative risk analysis for tunnels belonging to the trans-European road network and longer than 500 m, based on accident data. Strada dei Parchi S.p.A. is a company that manages a large number of road tunnels belonging to the A24 and A25 motorways in central Italy. In the course of recent modernization work on several tunnels, Strada dei Parchi S.p.A. has decided to set up and train emergency teams as a measure to further reduce the risk to tunnel users.
This paper discusses the effectiveness of emergency teams during major events, in particular fire accidents. The effect of emergency teams on road tunnel risk is assessed through a quantitative model implemented by Politecnico di Milano: TRAM - Tunnel Risk Analysis Model. The TRAM risk analysis model is able to assess the societal risk for the different tunnel configurations also taking into account the presence of emergency teams. Starting from two types of initiating events, fire and DG (Dangerous Goods) release, TRAM can consider up to 18 accidental scenarios occurring in different positions inside the tunnel under investigation. The main goal of the work is to analyze the effect of the presence of emergency teams in terms of reduction of the societal risk index for a representative tunnel; the resulting F-N (Cumulated Frequency - Number of Casualties) curves are also compared with the ALARP acceptance criterion. This study is divided into three main parts. The first part of the study describes the tunnel infrastructure and the equipment of the emergency teams; the second part is related to the description of the risk model with respect to the effectiveness of the emergency teams and, finally, the third part describes an application of this model to a case study. The effectiveness of the emergency teams and, in particular, their ability to control or extinguish the fire principles is analyzed using observations made inside the tunnels of the A24/25 motorways which were recorded and provided by Strada dei Parchi S.p.A.