In the event of a fire, the system automatically detects where in the tunnel the fire has occurred. Based on this and other relevant input it then determines which signals are to be communicated to which persons in the tunnel depending on where they are located.
EvacSound differs from existing Public Announcement (PA) systems in a number of ways. Firstly, the guiding signals that the system sends out are to a great extent aligned with human intuition. Hence, the system will function independently of road users' languages or cultural backgrounds. Secondly, when fully developed, the system will be self-calibrating, without dead zones, and compensate for any physical parameters that may degrade the quality of the transmitted signals. In addition, the system enables bidirectional communication between the tunnel and traffic management center. The operator can thus respond to calls for help or similar and precisely guide rescue personnel to the right place, quickly and efficiently.
Additional information can be found on the home page of the Norwegian Public Roads Administration.