Systems thinking in road tunnel safety: Feasibility of evacuation shelters for single-tube road tunnels

The self-rescue principle is fundamental for ensuring tunnel user safety during fires. Major fires in European road tunnels in the late 1990s and early 2000s highlighted the difficulties of evacuating single-tube tunnels with bi-directional traffic and longitudinal ventilation, resulting in an increased emphasis on facilitating self-rescue in road tunnels. This article explores the feasibility of shelters, abbreviated to SWETO, as an element in the evacuation system for existing single-tube road tunnels with bi-directional traffic and longitudinal ventilation. The study is a response to recent years’ increased interest in the concept in Norway. Integrating SWETOs presents both engineering and sociotechnical challenges. Functional requirements and solutions are lacking and need developing. However, it is argued that available knowledge supports the concept. A gradual integration of SWETOs in selected high-risk road tunnels is proposed through pilot projects. To increase our understanding of SWETOs effectiveness and limitations, knowledge-generating activities such as pilot projects and targeted research are crucial. These efforts should focus on their design, implementation, operation and maintenance to ensure functionality during emergencies. By addressing these aspects, SWETOs can become a valuable component of tunnel safety systems, enhancing the resilience of road tunnels and protecting tunnel users in critical situations. • The Mont Blanc tunnel fire in 1999 resulted in a prohibition of shelters in the EU. • Shelters can contribute to self-rescue during fires in single-tube, bi-directional tunnels with longitudinal ventilation. • The available knowledge associated with tunnel safety and shelters has developed greatly since the prohibition. • A general prohibition of shelters is counter-productive for innovation and enhancing safety. • Designing an adequate safety concept which incorporates shelters is a manageable engineering task.