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Everything You Ever Wanted To Know About Police Sirens

Everything You Ever Wanted To Know About Police Sirens

Everything You Ever Wanted To Know About Police Sirens


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Sirens play a vital role in policing. From being able to warn others that an emergency response vehicle, fire truck, or law enforcement response is underway, to help save lives by clearing traffic, there is virtually no end to the number of benefits of sirens. But, when did the police start using sirens? And do all law enforcement agencies use it? Can you use sirens as a civilian? Below, we’ll help answer all your questions about sirens and teach you everything you ever wanted to know about police sirens.

Origins of the Police Siren

John Robinson of Scottland is credited for creating the first siren in 1790. However, it was created to be used as an instrument rather than a warning detection of sorts, as it is used today. The siren has a distinct shrill wail that, unless you’re producing music for a horror movie, is quite distinct and not fit for a musical instrument.

When the Siren Was First Used

The first sirens were used to attract other types of emergency personnel, mainly volunteer firefighters! In France, volunteer firefighters were sometimes called using bells placed atop churches. However, since the invention of the original siren, and since it began to develop more along with electricity, churches would opt for using sirens instead of bells to alert volunteer firefighters that their services were needed.

Later on, siren tones were also used during the second world war in Britain to warn citizens of incoming air raids and invasions. Although it has a somewhat grim past, there’s no denying that without use in the war, the siren would not have developed into the essential piece of police equipment it is today.

The Police Siren in America

In the 1920s, coincidentally, when the United States was amid prohibition and criminals like Al Capone, police departments began to implement the use of police sirens. In the 1940s, they added lights, such as the blue light and red light we are familiar with today.

In 1965, the first electronic siren was invented by Ronald H. Chapman and Charles W. Stephens, two employees of the giant tech company Motorola. Since the invention of the siren, police officers have now freely implemented electric sirens into their everyday ventures. This electric siren mimics the mechanical siren but only needs to be plugged into an electrical source to produce its distinct siren sound.

Flashing lights and sirens together form a powerful combination to help alert traffic that a police car is near them, police officers are fast approaching, or fire is near.

How Does the Siren Sound Work?

Sirens were originally made out of mechanical components consisting of two discs. While one disc spins, the other stays in place, so that the air in between the two discs produces the wail that is now standard on police sirens.

Of course, using the siren on police cars was a bit difficult before the 1960s. During this time, an emergency vehicle or police vehicle had to install a police siren manually, which made it excessively heavy and not as fast to drive and chase down criminals.

Emergency vehicle drivers also had to power a mechanical siren placed on a fire truck. This siren would be placed in the front bumper of a fire truck and would be turned with a mechanical crankshaft that would give it its distinct, loud wail. Fortunately, firefighters and emergency services in fire trucks and police vehicles no longer have to turn a shaft to produce sound!

Using the Police Siren Today

Fortunately, a modern emergency vehicle and police cars now use an electronic siren and siren sounds created and amplified by speakers rather than huge, mechanical parts.

The modern police siren is distinct, perhaps because it uses a combination of different tones including:

  • Wail
  • Yelp
  • Perce/priority/phaser
  • Hi-lo
  • Scan
  • Airhorn
  • Manual

The most popular of these sounds is the wail, which can be easily heard from down a busy street and in heavy traffic. Yelp is best suited for urban areas with tall skyscrapers. Not only do these areas suffer from heavy traffic and distracted drivers, but they are also prone to dampening sound. A yelp tone can help bounce off skyscrapers, therefore alerting pedestrians and helping clear up congestions.

The same can be said of piercer or phase sirens, which sound like harsh repeated tones one after the other. The piercer siren can be used to alert inattentive drivers or to break through the sound of a loud music festival or even a parade.

Hi-lo sounds are not heard too often in the United States. This is the sound most people hear in cartoons or other renditions of a police siren. This sound consists of an ee-oo-ee-oo sound that can help alert traffic that a second emergency vehicle, fire truck, or police car is on its way.

Finally, an air horn is standard on all cars, including a police cars. The air horn is essential if a police officer wants to personally alert another vehicle without using its sirens, such as honking to them that they left their trunk open or need to pull over.

Whether it’s an emergency, emergency management situation or other scenario, police sirens all have distinct sounds that trained officers to know when to use…and when not to use.

Can Police Officers Use Sirens All the Time?

Most police departments and law enforcement agencies will have their specific policies on when to use a wail, yelp, sirens with flashing lights, or only flashing lights.

For instance, an officer might not be able to use their sirens to initiate a traffic stop, and might only have the ability to use a single yelp. These policies will vary based on the local fire department, local police department or transportation department regulations, and even state laws.

How Loud Are Sirens?

The sound waves of a siren are anywhere between 110-120 decibels, which is about the same as a fire truck and other emergency vehicles. However, sirens on police cars can sound a bit louder than an ambulance or other emergency services vehicles. This is because the electronic siren is mounted on the front of the vehicle, which gives it a distinct pitch and helps alert a driver to clear traffic and move over, or even to pull over for a traffic stop.

Can I Use Sirens On My Car?

There are various laws in place to prevent the use of sirens and flashing lights for regular drivers. If you’re the driver of your vehicle on your property, you might be able to use a siren for your benefit, such as to help secure your property and conduct security checks.

However, due to the loud noise of the siren, you might be subject to noise complaints or even a ticket for disturbing the peace. Many states and local counties only allow an authorized emergency vehicle, such as a police car, fire truck, or ambulance, to use sirens on the road.

It’s important to check with your local laws to make sure you can use sirens and flashing lights on your vehicle. For instance, if you’re a volunteer firefighter or police officer, you might be able to use sirens and flashing lights on your way to an emergency where lives are at risk. 

Again, laws will vary by state, so as a driver, it’s your responsibility to understand the laws before outfitting your car with a siren. When installing a siren, you should also make sure to outfit your vehicle with the right system. A mechanical siren might be complicated to fit into your vehicle, while an electronic siren might need extra rewiring to input.

What to Do When You Hear a Siren

Don’t panic. Pull your vehicle over to the side of the road and wait for the police car or other emergency vehicle to pass by you. If you’re in the United States, you must pull over to the right side of the road. If you’re in other parts of the world, you might need to pull into the left side of the road.

If an officer is initiating a traffic stop and turns on their lights and sirens behind you, wait for it to be safe before you pull over. These are simple safety tips that can help prevent personal injury.

Final Thoughts

From being a failed music instrument to being synonymous with crime and even rescue, the police siren is a staple of law enforcement. Understanding its rich history and knowing the subtle differences in siren tones can help you appreciate the siren even more, and know how to react when you hear it come towards you.

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