Sounding the alarm: The role of siren frequencies in emergency response safety

All over the country, first responders risk their own safety in order to protect and serve our communities. One of the most dangerous times for EMS, fire, and police forces responding to 911 calls is when they are behind the wheel, on the road en route to their destination. In order to safely clear intersections when emergency response is necessary, first responders operating vehicles with lights and sirens are taught to vary the frequencies of their sirens as they approach, enter, and clear the area. The purpose of this is to better catch the attention of civilians in their vehicles and on the streets who may have become unaware of the approaching units due to the monotonous sound pattern of the siren. The hope is that switching between frequencies at the approach of an intersection, then again as the vehicle enters the intersection, will startle those around to allow for more awareness of the first responders crossing their paths. This study seeks to find if this method is effective in its purpose of eliciting startle responses, and furthermore to find which sound patterns have the greatest effect. In order to put this question to the test, our study utilizes a behavioral chamber to observe the startle responses of seven wild-type mice subjects, along with one prairie vole as a control. The animals were placed into a behavior chamber, one at a time, and subjected to an array of different startles recorded from an ambulance siren. These files included three sound patterns, each played at different decibels with startle lengths of both 20 and 100ms. From there, the resulting startle responses were recorded as quantitative data and graphed in order to display the varying effects of each sound pattern and frequency on the reaction of the animals.