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Train Horns On Trucks: How, Why, and Is It Legal?

Truck owners love to show off and toot their horns in more ways than one. Train horns for trucks will attract a lot of attention when you let it rip. You can use your truck air horn to announce your arrival, say goodbye when you leave, or wake up that driver who pulled out in front of you. However, don’t be surprised if you upset the neighbors or others on the road if you decide to toot your horn.

So how and why are trucker drivers putting air horns on their trucks? Is it even legal? Let’s take a look and see what we can find!

Ylvis | Elbil med toghorn | discovery+ Norge
Watch it with subtitles but this is pretty funny

What Is a Truck Air Horn?

Air horns are commonly installed on big rigs like semi-trailer trucks, trains, and fire trucks. The reason you find louder air horns on these vehicles is that they already have an air system on board. Air is used for suspension and braking systems on these vehicles, so adding a horn is simple.

These horns often allow truck drivers to warn other drivers of their presence from a long distance. The horns use compressed air to pass through the horn into a reed or a diaphragm. The burst of air causes a vibration in the horn, which makes sound waves travel into it. Its unique shape amplifies the sound. When a truck air horn gets used, it’s nearly impossible not to hear it.

Motorhome Air Horn
Most Trucks, Busses and Large RV’s have air horns because they already have compressed air for their suspension and brakes

Why Have a Train Horn on a Truck?

If you’ve never been behind the wheel of a big, beefy truck, it’s hard to imagine just how different the driving experience is compared to a standard passenger vehicle. These huge vehicles, especially when towing a trailer, require more room and space to maneuver and slow down. When drivers need to alert other drivers, they need to be able to do so as quickly as possible. A train horn for a truck allows anyone to hear a truck’s horn up to 500 meters compared to a couple of hundred feet with a standard car horn.

Truck drivers use their horns to alert pedestrians, drivers, and even wildlife of their presence. A toot from their horn can help avoid an accident from an inattentive driver, wildlife wandering the road, or pedestrians not watching where they’re walking or riding their bike.

While you could argue that a louder horn can increase safety many times the intent of installing a train horn is strictly for making another aggressive modification. With a big loud truck, having a wimpy horn just feels wrong to many owners. You will also find some people who just love to be the most obnoxious person possible, and install them purely to annoy or make people jump because they think its funny.

Pro Tip: Before you upgrade your truck horn, find out What Mods You Should Do to Your Truck First.

Driver pushing car horn
Using a train horn instead of a standard horn will make it so the truck can be heard from further distances.

How Loud Is a Truck Air Horn?

While a standard passenger car horn will typically be somewhere between 100 to 110 decibels, a truck air horn can be upwards of 150 decibels. There’s a substantial difference between 100 decibels and 150 decibels because the scale is logarithmic.

Humans begin to experience pain from noises at 125 decibels, and short-term exposure to sounds greater than 140 decibels can cause permanent damage. Luckily, truck air horns are for outside use and for very short periods, so there are minimal risks of injuries or hearing loss.

Vehicle laws vary considerably by state, so check the requirements based on your state. However, Arizona, California, and Florida are the least friendly for truck air horns. Florida’s traffic law says, “No horn or other warning device shall emit an unreasonably loud or harsh sound or a whistle.” What one person considers “unreasonably loud or harsh” may differ. Many police will pull you over and ticket you for any modification that is considered unreasonable but this is usually debatable as unreasonable is subjective.

Regarding legalities, it’s essential to consider when and where you’re using your horn. Most states laws say that drivers can “when it is reasonably necessary to ensure safe operation, give audible warning with his or her horn but shall not otherwise use such horn when upon a highway.” So make sure you’re familiar with the laws in your neck of the woods. So if you use it to scare people or just be loud you can end up with a ticket.

If you want to read all horn laws by state, this list covers each state.

Truck driver entering into truck
Truck horns are louder than regular vehicles to better alert other drivers on the road.

How Loud Is a Real Train Horn?

Train horns are very powerful air horns that can produce anywhere from 130 decibels to 150 decibels on average. Like air horns on trucks, these horns increase safety and alert drivers and pedestrians of the train’s presence. You’ll primarily hear them as a train approaches a vehicular or pedestrian crossing. However, some cities and communities have laws prohibiting train horns. Be on the lookout for these “quiet zones” when crossing tracks.

How Much Does It Cost to Put a Train Horn in Your Truck? 

To install a train horn on your truck, you can pay anywhere from $200 to over $2,000. A decent train horn will require an air tank and air compressor. You’ll also need the actual train horn and all the wiring and hoses to connect all the parts. You can purchase kits with all the necessary equipment to get started.

If you’re not comfortable installing these yourself or want to get the best results, you’ll need to pay a pretty penny to have your kit professionally installed. However, the looks on people’s faces when you toot your horn will be worth every penny.

Pro Tip: Have you noticed a truck driver flashing their lights at you? Find out why they’re doing it!

Male truck driver driving
Easily upgrade the horn on your personal vehicle to a train horn with a few simple DIY steps.

Other Ways To Boost Your Truck Horn

If you’re unhappy with the sound or volume of your truck’s horn, there are a couple of easy solutions. First, just like your TV, you can turn up the volume. It relatively uncommon but some factory truck horns have an adjusting dial where you can turn up the volume. You may need to remove the horn from your truck to access it, but a simple clockwise turn can bump it up.

If your horn doesn’t have this dial, you’ll need to replace the horn with a louder one or one with a dial. You’ll need to disconnect the power and wire in the new horn. However, it’s a relatively simple process that just about anyone with some DIY skills can tackle. If your horn is larger, you may need to use a mounting bracket to secure the horn to your vehicle. Make sure you test the horn before wrapping up the project.

Best Train Horn On The Market For The Money

Are Truck Air Horns Worth It?

While train horns for trucks improve safety for you, other drivers, and pedestrians, most drivers opt to upgrade their truck horns for luxury purposes. It’s a fun upgrade that attracts attention and brings a laugh in some circumstances. However, in others, it may be overkill and induce road rage in a fellow driver. If you upgrade to a truck air horn, use it responsibly and know when it’s safe. Avoid being a nuisance to your neighbors or others on the road while using it.

Will you upgrade your truck horn? Tell us your thoughts in the comments!

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About Tom Morton

Tom, a Pacific Northwest native, is our technical genius. Born in Washington and raised in Alaska before settling in Michigan. He's the man who keeps our operation running, both figuratively and literally.

With a background in Electrical Engineering, Tom specializes in RV solar systems and lithium batteries. He made history as the first documented individual to use a Tesla battery module as an RV battery. Tom has personally assisted countless RVers with system installations and has educated thousands more through his videos and articles.

Cinematography is another of Tom's passions, showcased in his work on the Go North series. You can see his camera skills on display in The RVers TV show on Discovery Channel and PBS where he also stars as a co-host.

Tom's mechanical expertise extends beyond RVs to boats, planes, and all things mechanical. He's renowned for taking on maintenance and repair projects single-handedly and is often spotted underneath RVs, making him the technical backbone of our endeavors.

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