A police siren is the most effective device for warning people of an approaching police vehicle and effectively telling them to give way. While the police cars also use flashing lights to warn of their approach, a siren is more effective as it can be heard long before the lights are actually seen. It is understood when a siren is heard that the police car is going to be at a high speed and hearing a siren before actually seeing the car gives people time to move out of the way. There are situations, however, where even the police siren is not noticeable enough, and at times it falls on deaf ears. That's the case in very congested cities, like New York, where due to the excessive noise level sirens just don’t stand out. Issues also arise during the summer when windows are closed with air conditioners running at full blast and music playing – at these times, sirens are just not that obvious. With the ever increasing use of cell phones and people listening to iPods, even more challenges are presented.
For police officers, these sirens present a different type of problem. Having to listen to their own police siren sounds at close quarters too frequently can cause hearing problems. Although the officers are counseled to use ear protection, the problem persists. For people with health problems, the sudden loud sound causes blood pressure to rise.
Mr. Bader, vice president of a security firm, has been experimenting with a new type of a police siren. The new invention, called the Rumbler, and has a low frequency tone, between 180 to 360 hertz. This sound, when paired with the wail of the existing siren, makes a noise that is hard to ignore. People insulated from the street noise and protected behind a layer of glass and steel hear this police siren. Even New Yorkers, people with ear buds, and those talking on phones are not immune from this sound.
The best news is that the Rumbler is not louder that the existing standard siren. As a matter of fact, it is ten decibels lower, meaning it is only half the volume. The low-frequency waves are able to penetrate cars better than the existing higher pitch sirens; thus, drivers experience the new siren as being louder than the conventional siren. The Federal Signal explains the Rambler as an “intersection-clearing device”. Officers testing it have used on stretches of highway with good results
The new siren has been tested in various municipalities and the New York Police Department. The NY Police Department liked what it saw and is planning to adapt it in their cars. Besides for sending out a loud sound, the new police siren has a very low tone. It is this low tone that sends vibrations through vehicles to get the driver’s attention. To give the officers ears a well deserved break, the device stops after eight seconds.
The low-frequency sound can have physical effects and make one feel nauseous. The rambling effect of the Rambler, however, is rather subtle. It is significantly less than what one would feel if they were at a stop sign standing next to a car with speakers blaring and thunder bass thumping. The New York Police Department is giving this new sound the thumbs up for future use in more than eight thousand of their vehicles.