A practical approach for the evaluation of acceptable risk in road tunnels

In many European countries it is common to adopt quantitative criteria in evaluation of acceptable risk in road tunnels. Such criteria, usually expressed by FN-criteria and IR-values, will easily lead to a regime that is difficult to adopt in practice, as the use of such criteria requires extensive analyses and documentation for all types of tunnels. In this paper, a more practical approach for the evaluation of acceptable risk in road tunnels is presented, in which quantitative risk acceptance criteria are used for some road tunnels, while qualitative criteria are used for others. This means that varying degrees of effort and documentation are necessary for the evaluation of acceptable risk in road tunnels. The approach suggested is inspired by challenges in Norway.