Influence of Acoustic Tunnel Monitoring Akut on Tunnel Safety

The acoustic tunnel monitoring system AKUT is used in Austrian motorway tunnels since 2015 to detect critical events during tunnel operation. Through the automatic acoustic detection of unusual noises, the system detects potentially dangerous conditions or abnormal noises. By increasing detection possibilities, detection times can be reduced and subsequent traffic control as well as safety and rescue measures can be implemented faster. This can reduce the risk potential in case of an accident. Since the first installation of AKUT the detection times have been recorded in an event database, which is continuously updated. On this basis the detection times with and without AKUT can be objectively evaluated and the safety benefit of the system can be determined: Faster event detection allows for faster activation of safety equipment. Faster activation of traffic lights at the portal prevents people to enter hazardous zones. Faster activation of warning systems can reduce the subsequent accident rate after vehicle breakdowns and accidents. Based on the event data, an approach for the tunnel risk model TuRisMo has been developed. This has included establishing statistical fatalities numbers for the model tunnels selected through detailed fire simulations. Subsequently, reduction factors for application in the standard risk analysis model have been extracted. In this paper, the influence and changes to the event tree of the Austrian instruction RVS 09.03.11 will be presented. The result of the study allows a databased quantitative consideration of AKUT as an additional safety measure in road tunnels.