In the recent years various tools have been elaborated which are intended to give the stakeholders involved a common view and understanding how the safety features of a tunnel are interacting and how the tunnel interacts with its surroundings and the environment. They should also help to efficiently organise the decisions and actions required in order to ensure an adequate and constant safety level throughout the lifetime of a tunnel. These tools shall be able to summarize the current safety status of a tunnel in order to support management decisions regarding tunnel safety.
The safety documentation shall be an up-to-date safety record of a tunnel, providing a proper overview of all safety-relevant aspects and their current status. Risk assessment can be used for an in-depth analysis and quantification of these aspects, thus also providing quantitative information on the effectiveness of specific risk mitigation measures for an individual tunnel. Risk assessment tools are therefore often used to support decision making regarding the requirement of additional safety measures as well as for the selection of the best suitable combination of measures, which is in particular relevant for improving safety of existing tunnels. For hazards caused by a release of dangerous goods specific risk models are available.
Information on the current status of the safety systems of a tunnel is gained by regular tunnel inspections whereas learning from practical experience can be assured by a systematic collection and evaluation of real incident data. Regular emergency exercises and training of emergency services improves the preparedness for incidents which can never be completed excluded by preventive measures.