Probabilistic risk analysis in road tunnel safety

This article suggests a methodology of the risk index assessment connected to the one-way and two-way road tunnel crossing, based on the use of Probabilistic Risk Analysis. This study is included in the course of an extensive research programme started by the Department of Transportation Engineering “L. Tocchetti” – Naples University “Federico II”; the final goal of this research is the interpretation of the system man-vehicle-road tunnel environment (where service management for users gathers unusual prominence); the started programme also includes an experimental physical and virtual survey of the speed into road tunnel. We have specialized a general methodology, with applications in different fields of Engineering, on the basis of a detailed and complete database of the car-crashes (reconstructed by Police minutes) occurred between 1997 and 2002 in all road tunnels in the province of Salerno. Particularly in-depth analysis, carried out until now, has given the possibility to create an event tree for the accident probability determination in both types of the road tunnels (one-way and two-way) and as many fault trees as typical accidental sequences are reconstructed. Besides, we have determined the consequences size distribution (in terms of dead, injured and damages) of occurred accidental events, on a statistical basis. So we have planned the means for the risk index determination connected to the undesired event in one-way road tunnel accident and in two-way road tunnel accident; after stating the means clearly there will be surely a detailed numerical application realizable only by a close and reasoned data finding, that isn’t organized in a proper way to the request of this procedure, concerning the road tunnels (at a national level too).