Perceived Effectiveness of The Rumbler Emergency Siren System

The Rumbler: Intersection Clearing System is an emergency vehicle siren technology used in conjunction with a traditional emergency vehicle siren system to improve acoustical performance through the addition of a low frequency modulating sound wave. Psychoacoustic evaluation was conducted to determine how the Rumbler is perceived subjectively, by using a noise, vibration and harshness (NVH) driving simulation to conduct the acoustical perception jury evaluation. Twenty-three jurors participated in the evaluation of emergency vehicle siren sounds, comparing the standard siren sound with and without the addition of the Rumbler system. It was found that the detection accuracy was nearly twenty five percent higher in terms of the number of jurors who were able to correctly determine the direction of the oncoming emergency vehicle when the Rumbler was implemented in addition to the wail siren. Furthermore, the addition of the Rumbler system resulted in the siren sound to be perceived as louder, harsher, more alarming, more urgent, and more distinct. The psychoacoustic evaluation proved that incorporation of the Rumbler increased the siren's overall effectiveness. Based on this conclusion, it was recommended that the Rumbler be implemented on emergency vehicles to enhance the effectiveness of the system.