System for Deterministic Risk Assessment in Road Tunnels

In this paper, a pragmatic and goal oriented system for risk analysis in road tunnels is described. It is particularly focusing on mortality risks in case of a road tunnel accident. It is a deterministic approach combining three major components: a) vehicle distribution in a tunnel; b) smoke propagation in case of a fire; and c) people evacuation (escape) component. The major improvement of this approach is in capturing the knowledge often provided only by experts into a robust and pragmatic system available to all decision makers. This is achieved through a large number of scenarios combining different configurations of road tunnels (e.g. different number of lanes, different speed limits) and the travel demand (e.g. different structure of the flow, different volumes of traffic) which were prepared and evaluated through microscopic traffic simulation. The resulting scenarios with the information about the number of vehicles in different tunnel sections were obtained. The results describe most of the existing tunnels and situations and can be used universally. Similarly, the people evacuation component can be evaluated in a general form. The results can be manually updated to suit any particular road tunnel which can differ for example by the availability or quality of warning and information systems. The remaining task is to create a physical model of the real tunnel and to model the smoke and fire propagation. All these components were combined into the CAPITA software that was developed as a part of the research project HADES (supported by the Technology Agency of the Czech Republic). The CAPITA software is presented in the last chapter of this paper. The scenarios available off-line are in fact a knowledge base available to experts as well as decision makers and lead to a higher level of comprehension of the developments in case of fire and significantly speed up preparation of a risk analysis.