To ensure safety in road tunnels, the necessary structural, technical and organisational measures need to be put in place so that incidents can be prevented as far as possible and their impact can be kept to a minimum. The level of safety in tunnels is influenced to varying degrees by a variety of factors that can be collectively summarised in four main groups: Road Users, Infrastructure, Vehicles, and Operation.
Most of the measures needed to ensure a safe tunnel are based on the above influencing factors and aim to prevent or mitigate the danger which arises from incorrect user behaviour, inadequate tunnel installations or operation, vehicle technical defects or other faults. See Chapter 1 "Why are tools for tunnel safety management needed?" of report 2009R08.
All the above necessary safety measures have to be combined under effective tunnel safety management. To maximise the effectiveness of tunnel safety management, certain tools are needed to support strategy, to drive critical decisions and keep a constant and traceable focus on all safety issues, over a tunnel's lifetime. The three major "tools" for tunnel safety management are described below.
Safety documentation is a key aspect of safety management and should be compiled for each tunnel. The demands for this information are different depending on which stage the tunnel is at in its life-cycle: design, commissioning, or operation. At the design stage the safety documentation focuses on the description of tunnel infrastructure and traffic forecasts, whereas at the operation stage the operational aspects, such as emergency response plans and measures for transportation of dangerous goods, gain importance. The degree of detail in the information increases as the project develops. The safety documentation should comprise'living' documents which are continuously developed and updated; including detailing changes in tunnel infrastructure, traffic data, etc, as well as important findings from operational experience (i.e. analysis of significant incidents, safety exercises, etc.). More information is available on Chapter 2 "Road Tunnel Safety Documentation" of report 2009R08.
Collection and analysis of incident data, as detailed on Chapter 3 "Collection and Analysis of Data on Road Tunnel Incidents" of report 2009R08 are essential for the risk assessment of a tunnel and for the improvement of its safety measures. These comprise a two fold process, starting at the local tunnel level to cover specific needs, like input data for risk analysis, and extends to fulfil legal obligations such as reporting statistics at national/international level. The evaluation of specific events (accidents and incidents) may help to identify specific hazards in a tunnel as well as to optimise operational procedures and the reaction of safety systems. As well as analysis for real incidents, analysis of data from safety exercises can help to gain experience in the management of incidents under realistic circumstances.
Practical issues of incident data collection are further addressed in Chapter 2 of the report “Experience with Significant Incidents in Road Tunnels”, based on the 3 fundamental steps of incident data collection and evaluation. Practical problems and limitations are discussed and recommendations for improvements are given.
Safety inspections, as explained in Chapter 4 of the technical Report 2009R08 (Safety Inspections of Road Tunnels) are a tool to assess the current tunnel safety level either within a legal framework (European Directive for instance) or against an accepted level of risk. PIARC has developed an organisational scheme based on the EU Directive 2004/54/EC to describe the chain of safety responsibility concerning safety inspections and clarify the responsibilities of the involved parties. It also proposes the contents of a safety inspection (infrastructure and systems, safety documentation and existing procedures, tunnel management organisation, training and quality assurance) along with a comprehensive roadmap with all the necessary steps and preparation needed to carry out a safety inspection.