Evaluating the role of risk assessment for road tunnel fire safety: A comparative review within the EU

Fire is the foremost critical event for road tunnels' safety. Therefore, the European Commission introduced the Directive 2004/54/EC for enhancing tunnels' safety since they constitute a key element of the Trans-European Road Network. The Directive has established a common ground for tunnels' safety evaluation providing certain minimum requirements while introducing officially the use of risk assessment. Despite the significant progress, this paper illustrates that further efforts are needed. Through a comparative review of the risk assessment methods, questions about the level of harmonisation of the framework are raised. Moreover, considerable problems are highlighted, like the incorporation of the new trends emerging from the literature or the deficiencies on addressing significant issues of the analysis, such as the risk acceptance criteria and the behaviour of trapped-users. These problems can affect the risk assessment process causing both significant discrepancies and deficiencies at the estimated level of tunnels' safety. Uncovering, thus, the deficiencies and limitations of the methods, this paper contributes to i) the discourse for initiating relevant studies to enhance tunnels’ fire safety in Europe and worldwide, and ii) the harmonisation of risk assessment methods.