With the increasing number of tunnels under construction or in planning throughout the world, and the growing volume of traffic using existing tunnels, safety issues are becoming increasingly important. Incidents and collisions in road tunnels may be no more frequent than those on the open road, indeed road tunnels can provide a safer, more controlled driving environment for road users. However, the consequences of major incidents in the confined tunnel environment are potentially significantly more severe than on the open road and usually raise stronger reactions from the public.
A safe tunnel environment can only be achieved by an optimized and balanced interaction of all aspects influencing safety, including infrastructure, equipment, user behaviour, operational practices and emergency response procedures. This holistic approach as well as other safety principles are the key to a state of the art tunnel safety management.
The basis for an in-depth discussion of tunnel safety is a proper understanding of the specific hazards in road tunnels, which may affect health and safety of tunnel users, their property, tunnel infrastructure or environment.
A safe tunnel system requires the implementation of efficient safety measures which can be defined by regulative requirements and/or tailored to the specific conditions of an individual tunnel. Decisions on safety measures should always be taken from a holistic point of view, focussing on a smooth interaction of the various systems and balancing the requirements of tunnel users, tunnel operation, tunnel maintenance and cost.
To achieve this goal a set of well-established tools for tunnel safety management is available to support tunnel managers in decision-making and maintaining a high safety level throughout the whole lifetime of a tunnel.
The operating conditions of a road tunnel are seldom constant, and many events or hazards can potentially threaten its availability. Therefore, “resilience” is an important consideration in the safe operation and maintenance of the tunnel as a system. The technical report Improving Road Tunnel Resilience, Considering Safety and Availability - Technical Report captures the general concepts and approaches for resilience management. Along with criteria and requirements for resilience management, availability and safety.