Truck air horns

Vehicle air horns  are a popular addition to trucks, partly because they give a loud, deep warning signal, but also because of the attractive appearance of the shiny chrome or stainless steel. A normal horn makes a sound through magnets on a membrane, while the sound of an air horn is generated by compressed air. The truck air horns are often already fitted to order by the truck manufacturer, such as Scania, Mercedes Actros or Iveco. If truck air horns are retrofitted, it is essential that the existing horn still works. Any additional lorry air horns must be operated separately. Road traffic laws regulate the use of horns or vehicle air horns  in traffic. You are only allowed to use your horn to warn other road users of danger or to alert them to your presence. In some countries, you are allowed to briefly use your horn outside built-up areas to announce your intention to overtake. Sound sequences are only permitted for special operations vehicles with a corresponding signal horn. However, double horns are permitted as they do not produce a sound sequence. The maximum sound pressure level of an air horn or compressed air fanfare must not exceed 105 dB (A), which is loud enough. The term foghorn refers exclusively to ships. A compressed air horn may only be used as a foghorn in road traffic when visibility is poor and to avert immediate danger.

Using air horns for cars

A 12V compressor is required for using air horns for cars. Unfortunately, cars do not usually come with compressed air on board. A compressor electrically generates compressed air at the correct pressure in bar to operate an air horn or fanfare. Popular fanfare air horns for cars with sounds sequences are also not permitted.