Experience from past tunnel incidents

The major fire incidents of Mont Blanc, Tauern and St. Gotthard (1999 and 2001) led to an increased awareness of the possible impact of incidents in tunnels. The likelihood of escalation of incidents into major events is low, however the consequences of such incidents can be severe in terms of victims, damage to the structure and impact on the transport economy.

An international survey of major tunnel fires can be found in the technical report 05.16B « Systems and equipment for fire and smoke control in road tunnels, Table 2.1 "Serious fires accidents in road tunnels".

These catastrophes demonstrated the need for improving preparation for, as well as preventing and mitigating, tunnel incidents. This can be achieved by the provision of safe design criteria for new tunnels, as well as effective management and possible upgrading of in-service tunnels, and through improved information and better communications with tunnel users. Conclusions drawn from the enquiry following the Mont Blanc tunnel fire were that fatal consequences could be greatly reduced by:

• a more efficient organisation of operational and emergency services (harmonised, safer and more efficient emergency procedures, specifically for cross-border operation),
• more skilled personnel,
• more effective safety systems and
• greater awareness among users (car and truck drivers) on how to behave in emergency situations.

After the fire of March 24th 1999, the Mont Blanc tunnel required significant renovation before it was able to be reopened to traffic.

A detailed description of the Mont Blanc, Tauern and St. Gotthard fires including the original configuration of the tunnels, and a step-by-step guide to the incident, fire progression, and the behaviour of operators, emergency services and users, as well as the lessons to be drawn can be found in the technical report 05.16B « Systems and equipment for fire and smoke control in road tunnels. Chapter 3 "Lessons learned from recent fires". The lessons learnt are summarised in Table 3.5 of this report. Similar information is given in Routes/Roads 324 "A comparative analysis of the Mont-Blanc, Tauern and Gotthard tunnel fires" (Oct. 2004) on p 24.

However, characteristic events are fortunately rare, and may be limited to specific circumstances. Hence a systematic analysis of less severe, but more frequent incidents (collisions and fires) may provide a more representative picutre of real tunnel incidents. Appendix 5 of the technical report 2016 R35 “Experience with Significant Incidents in Road Tunnels” provides a survey of 32 randomly selected real tunnel incidents, including a short description as well as important conclusions and improvements that could be identified for specific types of incidents or tunnel systems.

Some lessons learned can be given as examples, such as:

• misbehaviour of car drivers seems to be the most common cause of tunnel incidents and may also cause problems in incident management (like impeding access of emergency services to the site of incident)
• in case of a fire drivers sometimes try to pass by the vehicle on fire to continue their ride, despite the potential danger caused by fire and smoke
• traffic management measures – such as closing of a lane (eg. by red crosses) or closing of the tunnel (by traffic lights), are often neglected if not enforced by additional means (eg. like barriers for tunnel closure)
• problems of communication between the different stakeholders involved, which may be caused by various reasons, are a key issue in incident management
• the systematic evaluation of individual incidents often contributes to the optimisation of emergency response procedures and cooperation and training of all organisations involved in incident management

However, it is not possible to give generally applicable recommendations on the basis of these findings because these may be different in dependence of the specific conditions of an individual country and an individual tunnel.

Moreover, this report presents updated statistical data on tunnel collisions (Chapter 3) and fires (Chapter 4) for many countries. The data base used for the calculations are enclosed in Appendix 3 (collisions) and Appendix 4 (fires) respectively.

Further, well-structured and reliable information on tunnel incidents is of great importance as input data for quantitative risk assessment as well as to motivate improvements in safety systems and procedures. These topics are also addressed systematically in the technical report 2016 R35 “Experience with Significant Incidents in Road Tunnels”.

Earlier reports also present a statistical census of breakdowns, collisions and fires in selected tunnels, as well as the lessons to be drawn from such events for the geometric design of the tunnel, the design of the safety equipment and the operating guidelines: 

• Technical report 05.04B "Road Safety in Tunnels"
• Technical report 05.05B « Fire and smoke control in road tunnels, Chapter 2 "Fire risk and design fires"
• Technical report 05.16B « Systems and equipment for fire and smoke control in road tunnels »: Chapter 3 "Lessons learned from recent fires"; Table 2.1 "Serious fires accidents in road tunnels", Appendix 12.2 "The Mont Blanc Tunnel renovation".