Emergency vehicle equipment is the equipment fitted to, or carried by, an emergency vehicle, which is additional to any equipment such as headlights, steering wheel

Steering wheel

A steering wheel is a type of steering control in vehicles and vessels ....

s or windshield/windscreens that a standard non-emergency vehicle is fitted with.

Visual warning devices

Emergency vehicles of any kind (fire truck, ambulance, police car) are highly likely to be involved in hazardous situations, including relatively common incidents such as a road traffic collision. They are also required to gain access to incidents as quickly as possible, and in many countries, are given dispensation from obeying certain traffic laws; for instance, they may be able to treat a red traffic light or stop sign as a give way, or be permitted to break the speed limit. However, emergency vehicles usually are not able to treat a railroad crossing

Level crossing

A level crossing occurs where a railway line is intersected by a road or path onone level, without recourse to a bridge or tunnel. It is a type of at-grade intersection. The term also applies when a light rail line with separate right-of-way or reserved track crosses a road in the same fashion...

 as a give way, because a train cannot be warned in time to stop before the crossing to let the vehicle through. Hence, one of the few things emergency vehicles must yield to are heavy freight and passenger trains.

For these reasons, emergency vehicles in many countries worldwide, are fitted with visual warnings to alert members of the public (and in particular, other motorists and road users), either as they approach the vehicle, or it approaches them. Visual warnings can be of two types - passive warning or active warning.

Passive visual warnings

The passive visual warnings are usually inherently linked to the design of the vehicle, and involve the use of high contrast patterns. Older vehicles (and those in developing countries) are more likely to have their pattern painted on, whereas modern vehicles generally carry the retro-reflective

Retroreflector

A retroreflector is a device or surface that reflects light back to its source with a minimum scattering of light. An electromagnetic wave front is reflected back along a vector that is parallel to but opposite in direction from the wave's source. The device or surface's angle of incidence is...

 designs which reflect light from car headlights or torches (and was invented by 3M). Popular patterns include 'checker board' (alternate coloured squares, sometimes called 'Battenburg markings

Battenburg markings

Battenburg refers to a pattern of high-visibility markings used to maximise conspicuity, primarily used on vehicles of the emergency services, but also in other applications such as uniforms...

'), chevrons (arrowheads - often pointed towards the front of the vehicle if on the side, or pointing vertically upwards on the rear) or stripes (along the side - these were the first type or retro-reflective device introduced, as the original 3M reflective material only came in tape form). In some countries, in addition to retro-reflective markings, the vehicles are now painted in a bright yellow or orange colour underneath, in order to maximise visual impact.

Another passive marking form is the name of the emergency service spelled out in reverse on the front of the vehicle (e.g. Ambulance or Fire). This enables drivers of other vehicles to more easily identify an approaching emergency vehicle in their rear view mirrors. The vehicle may also display the name of their owner or operator, and a telephone number which may be used to summon the vehicle.
Ambulances may also carry an emblem (either as part of the passive warning markings or not). Some ambulances may display a Red Cross, Red Crescent or Red Diamond (collective known as the Protective Symbols

Emblems of the Red Cross

The emblems of the International Red Cross and Red Crescent Movement, under the Geneva Conventions, are to be placed on humanitarian and medical vehicles and buildings to protect them from military attack on the battlefield. There are four such emblems, three of which are in use: the Red Cross,...

). These are symbols laid down by the Geneva Conventions

Geneva Conventions

The Geneva Conventions comprise four treaties, and three additional protocols, that establish the standards of international law for the humanitarian treatment of the victims of war...

, and all countries signatory to it agree to restrict their use to either (1) Military Ambulances or (2) the national Red Cross or Red Crescent society. Use by any other person, organisation or agency is in breach of international law. The protective symbols are designed to indicate to all people (especially combatants in the case of war) that the vehicle is neutral and is not to be fired upon (see Military ambulances), hence giving protection to the medics and their casualties, although this has not always been adhered to.

Many ambulances use the Star of Life

Star of Life

The Star of Life is a blue, six-pointed star, outlined with a white border which features the Rod of Asclepius in the center, originally designed and governed by the U.S. National Highway Traffic Safety Administration...

, which indicates that the vehicle's operators can render their given level of care represented on the six pointed star.

Active visual warnings

The active visual warnings are usually in the form of flashing coloured lights (also known as 'beacons' or 'lightbars'). These flash in order to attract the attention of other road users as the emergency vehicle approaches, or to provide warning to motorists approaching a stopped vehicle in a dangerous position on the road (and if the emergency vehicle positions itself to deliberately move people away from an incident, this is called fend off). Common colours for emergency vehicle warning beacons are blue and red, and this varies by country (and sometimes by operator).

The lights can be made to flash via a range of techniques, dependent on the technology used, and the desired end effect. Types of beacon include:

• Light bar
  Light bar
  Emergency vehicle lighting refers to any of several visual warning devices, which may be known as light bars or beacons, fitted to a vehicle and used when the driver wishes to convey to other road users the urgency of their journey, to provide additional warning of a hazard when stationary, or in...
  
  s - A long but narrow 'strip' of lights on top of an emergency vehicle, which can be configured with almost infinite combinations of different lighting technologies from the list below. These are typically the main source of flashing light for the vehicle, and are used on overt marked emergency vehicles. They can also be divided in to sections, with an array of functions (for instance front blue flashing lights, and rear red flashing lights, switched separately). Due to the nature of the wind resistance encountered by these large units, the majority must be fixed to the car permanently, although some units (usually smaller) are available with either magnetic or suction cup
  Suction cup
  A suction cup, also sometimes known as a sucker is an object that uses negative fluid pressure of air or water to adhere to nonporous surfaces. They exist both as artificially created devices, and as anatomical traits of some animals such as octopi and squid.The working face of the suction cup has...
  
   mountings which can be removed. The Light bar may also contain the Audible Warning
  Siren (noisemaker)
  A siren is a loud noise making device. Most modern ones are civil defense or air raid sirens, tornado sirens, or the sirens on emergency service vehicles such as ambulances, police cars and fire trucks. There are two general types: pneumatic and electronic....
  
   devices
• Beacons - A simple lighting device, often found on smaller emergency vehicles, or unmarked cars, (where it is removable) and consists of a clear or transparent coloured casing surrounding a lamp and a revolving mirror. Some beacons consist of one or several lamps that revolve, instead of using a mirror. These were the original type of emergency vehicle lighting
• Alternating Vehicle Lights or Wig-wags
  Wig-wag (automobile)
  A wig-wag is a device for flashing an automobile's headlights at a preset rate. Traditionally, the wig-wag will flash the right and left headlights alternately, but some designs will flash both headlights on and off together...
  
   - This causes the Full beam headlights, or Fog lights to flash in a pattern (usually alternating left-right-left, although it can be together, or in a random pattern), and can also be used at the rear of the vehicle on Brake, Fog or reversing lights to warn vehicles approaching from the rear.
• Grille lights - Flashing lights fitted on, in to or behind the grille of the emergency vehicle, creating forward-facing flashing effects, designed to be seen in the rear view mirror of moving traffic in front of the vehicle. These can be fitted to both overt and covert emergency vehicles, by simply changing whether they are mounted internally or externally, or by varying the lens colour (so that they may look like fog lights on a covert vehicle)
• Dash Lights - These are forward-facing lights, like grille lights, but mounted on the dashboard of the emergency vehicle. They are more often found on covert vehicles, but may be found on some marked vehicles which are trying to increase visibility. In order to avoid dazzling the driver, they are normally fitted with 'shields' around the light which stop the light reflecting in to the cab.
• Deck lights (or Parcel Shelf lights) - Rear-facing equivalents of the Dash Lights which are placed on the Parcel Shelf of the vehicle. These can be used in both overt and covert vehicles.

• Directional Warning Arrows or arrow sticks - A strip of lights (typically amber or yellow) which light up in sequence to direct traffic to the right, left, or around both sides of an emergency vehicle. They may be found mounted on the back of a lightbar, on a car's package shelf (shining out the rear window) or on some other conspicuous location on the rear of a vehicle.
• Information Matrix Signs - These special active visual warnings are used to convey words to vehicles approaching from behind the emergency vehicle and often carry messages such as "Police. Stop" or other relevant message. Some systems allow only preprogrammed messages, where others can be fully customised.

Many governments list specific requirements for emergency vehicle lighting. These requirements may address the colour, location and intensity/visibility of the lights, and whether they should flash or burn steadily. Laws also may regulate what vehicles may display these lights, and under what circumstances they may do so.

Technically, the warning lights may be of several types, which includes:

• Incandescent - These are 'traditional' light bulbs, and may be found in the 'beacon' type lights, and will also be found where the vehicles own lighting is used (such as wig-wag). They may be of several types, including Halogen
  Halogen lamp
  A halogen lamp, also known as a tungsten halogen lamp, is an incandescent lamp with a tungsten filament contained within an inert gas and a small amount of a halogen such as iodine or bromine. The chemical halogen cycle redeposits evaporated tungsten back on to the filament, extending the life of...
  
   or Xenon
  Xenon lamp
  Xenon lamp may refer to:* Xenon arc lamp* Xenon flash lamp* An incandescent light bulb filled with xenon gas to improve life span or efficiency...
  
  . They may rely on an extra piece of equipment (such as a rotating mirror) to make them flash, or are simply turned on and off.
• Strobe light
  Strobe light
  A strobe light or stroboscopic lamp, commonly called a strobe, is a device used to produce regular flashes of light. It is one of a number of devices that can be used as a stroboscope...
  
  s - These lights give a short flash, which is usually very bright over a longer range than an incandescent light. They are usually made to work in multiples (such as three rapid flashes consecutively) and are often used in patterns between sets, which increases their effectiveness.
• LED
  LEd
  LEd is a TeX/LaTeX editing software working under Microsoft Windows. It is a freeware product....
  
   Lights - These are more recent developments, using the 'Super Bright' LED technology, and are entering wide use as they are easy to fit (being only a few millimetres wide, rather than several centimetres for most strobes and incandescent lights). This makes them particularly suitable for covert use. Though currently much more expensive than other types of lamps, there are substantial benefits. They draw much less electrical current than other types of lamps which is a valuable reduction in electrical load on these vehicles' over-stressed electrical systems. They are much more resistant to vibration and have much longer service lives. They also present very saturated colors and so enhance visibility during daylight hours.

Audible warning devices (sirens)

When an emergency vehicle is responding, it often uses audio warning devices in addition to the visual warnings provided by its warning lights. Audio warning devices are turned off once the vehicle is on-scene. Such devices include:

• Sirens
  Siren (noisemaker)
  A siren is a loud noise making device. Most modern ones are civil defense or air raid sirens, tornado sirens, or the sirens on emergency service vehicles such as ambulances, police cars and fire trucks. There are two general types: pneumatic and electronic....
  
   - These can be fully electronic
  Electronics
  Electronics is the branch of science, engineering and technology that deals with electrical circuits involving active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies...
  
  , electric, or manual, but are all designed to create changing sound patterns. These patterns vary by model of siren. Emergency drivers are often trained to use different siren tones in different conditions, to achieve maximum effectiveness through traffic. A long standing problem for emergency services has been traffic being unable to determine the direction a siren is approaching from, and different tones have been developed on some electronic sirens to help combat this, such as the use of white
  White noise
  White noise is a random signal with a flat power spectral density. In other words, the signal contains equal power within a fixed bandwidth at any center frequency...
  
   or pink noise
  Pink noise
  Pink noise or 1/ƒ noise is a signal or process with a frequency spectrum such that the power spectral density is inversely proportional to the frequency. In pink noise, each octave carries an equal amount of noise power...
  
   in between more conventional siren noises, which helps people to pinpoint their origin.
• Public address
  Public address
  A public address system is an electronic amplification system with a mixer, amplifier and loudspeakers, used to reinforce a sound source, e.g., a person giving a speech, a DJ playing prerecorded music, and distributing the sound throughout a venue or building.Simple PA systems are often used in...
  
   system - Sometimes linked to the electronic or electric siren, or possibly stand alone, this system allows the voice of the operator to be amplified to give direction. This is found especially useful in heavy pedestrian traffic.
• Air horn
  Air horn
  The air horn is a device designed to create an extremely loud noise. It is usually composed of a pressurized air source coupled to a horn through a valve which allows the device to be turned on and off. Air horns have been installed on large semi-trailer trucks, fire trucks, and some ambulances for...
  
   - These devices simply force air through a shaped pipe to create noise. They can be used to create the classic two tone 'nee naw' sound which led to the colloquial expression for lights and sirens on emergency vehicles of blues and twos
  Blues and twos
  Blues and twos is a colloquial British term that refers to the emergency vehicle equipment of combined flashing lights as well as sirens that the emergency services in the UK and Ireland use when responding to an incident...
  
  . They can be both mechanical and electronic.
• Bells
  Bell (instrument)
  A bell is a simple sound-making device. The bell is a percussion instrument and an idiophone. Its form is usually a hollow, cup-shaped object, which resonates upon being struck...
  
   - Usually found on older or classic emergency vehicles, these were the original methods of notifying people of the approach of emergency vehicles. They were first hand bells, and later replaced by electric versions.
• Exhaust whistle
  Whistle
  A whistle or call is a simple aerophone, an instrument which produces sound from a stream of forced air. It may be mouth-operated, or powered by air pressure, steam, or other means...
  
  s - These are no longer used, but still referred to in some legislation, and may be found on classic emergency vehicles, an exhaust whistle is fitted to a vehicle's exhaust pipe, and functions similar to a steam whistle
  Steam whistle
  A steam whistle is a device used to produce sound with the aid of live steam, which acts as a vibrating system .- Operation :...
  
  , with the exhaust gasses replacing the steam.

Some emergency vehicles operators may turn off their sirens when on side streets or when there are no cars on the road so as not to disturb residents. The driver will then turn on the sirens before proceeding through intersections or when traveling on potentially dangerous stretches of road.

Auxiliary lighting

Auxiliary lighting is light used for illumination, to supplement factory-installed headlights or to illuminate areas to the side of or behind the vehicle. It is typically white or near-white light. Some emergency scenes require additional lighting if the emergency workers are to be able to effectively deal with the emergency. Also, building numbers are often obscured by darkness, making it difficult for emergency workers to find the scene of an emergency. For these reasons, emergency vehicles are often equipped with auxiliary lighting, such as:

• spot-lights
  Searchlight
  A searchlight is an apparatus that combines a bright light source with some form of curved reflector or other optics to project a powerful beam of light of approximately parallel rays in a particular direction, usually constructed so that it can be swiveled about.-Military use:The Royal Navy used...
  
  , which may be mounted on the side, top, or rear of a larger vehicle, or on the A-post/A-pillar of smaller vehicles.
• flood lights, which may similarly be mounted on the side, top, or rear of a larger vehicle.
• load lights, which are used by ambulances and other vehicles with cargo doors to light up the area around the cargo doors.
• alley lights, which are typically found mounted on the side of a police car
  Police car
  A police car is a ground vehicle used by police, to assist with their duties in patrolling and responding to incidents. Typical uses of a police car include transportation for officers to reach the scene of an incident quickly, to transport criminal suspects, or to patrol an area, while providing a...
  
   or emergency vehicle
  Emergency vehicle
  An emergency vehicle is any vehicle that is designated and authorized to respond to an emergency. These vehicles are usually operated by designated agencies, often part of the government, but also run by charities, non-governmental organizations and some commercial companies...
  
  's lightbar
  Light bar
  Emergency vehicle lighting refers to any of several visual warning devices, which may be known as light bars or beacons, fitted to a vehicle and used when the driver wishes to convey to other road users the urgency of their journey, to provide additional warning of a hazard when stationary, or in...
  
  , for the purpose of illuminating areas to the side of the car, such as into an alley, or a scene at the side of the road.
• take-downs, which are typically mounted on the front of an emergency vehicle
  Emergency vehicle
  An emergency vehicle is any vehicle that is designated and authorized to respond to an emergency. These vehicles are usually operated by designated agencies, often part of the government, but also run by charities, non-governmental organizations and some commercial companies...
  
  's lightbar. Take-downs are used on police cars to illuminate the interior of a vehicle immediately in front of the police car, such as a vehicle that has been pulled over after committing a traffic violation or while conducting a high-risk vehicle stop (also called a felony stop). The bright lights also serve to blind the vision of suspects looking back toward the police. take-downs are also used on ambulances and other vehicles to illuminate a work area in front of the vehicle, such as a patient in the roadway, an accident scene, or a fire scene.

Communications devices

Efficient emergency responses require that emergency responders can communicate with a dispatcher

Dispatcher

Dispatchers are communications personnel responsible for receiving and transmitting pure and reliable messages, tracking vehicles and equipment, and recording other important information...

, with each other, and often with other facilities (such as hospitals or public utilities). Emergency vehicles are equipped with the following types of equipment to do so:

• two-way radio
  Two-way radio
  A two-way radio is a radio that can both transmit and receive , unlike a broadcast receiver which only receives content. The term refers to a personal radio transceiver that allows the operator to have a two-way conversation with other similar radios operating on the same radio frequency...
  
  , usually operating on dedicated frequencies and channels designated for emergency use, or in some cases simply a CB radio.
• portable two-way radios, which transmit and receive on the same frequencies as the built in two-way radios, but are less powerful. Emergency workers can take these radios with them when they exit the vehicle. There are also systems (frequently referred to as mobile extenders or mobile repeaters) that allow the portable radios to be relayed through the vehicles more powerful two way radio. Some emergency services encrypt their radio transmissions.
• car phone
  Car phone
  A car phone is a mobile phone device specifically designed for and fitted into an automobile.In the late 1970s and 1980s, the car phone was more popular than the regular mobile phone...
  
  s or portable cellular phones.
• mobile data terminal
  Mobile data terminal
  A mobile data terminal is a computerized device used in public transit vehicles, taxicabs, courier vehicles, service trucks, commercial trucking fleets, military logistics, fishing fleets, warehouse inventory control, and emergency vehicles to communicate with a central dispatch office...
  
  s, or MDTs, which are computers that communicate with the dispatcher's computer.
• Laptop
  Laptop
  A laptop, also called a notebook, is a personal computer for mobile use. A laptop integrates most of the typical components of a desktop computer, including a display, a keyboard, a pointing device and speakers into a single unit...
  
   computers with Wi-Fi
  Wi-Fi
  Wi-Fi or Wifi, is a mechanism for wirelessly connecting electronic devices. A device enabled with Wi-Fi, such as a personal computer, video game console, smartphone, or digital audio player, can connect to the Internet via a wireless network access point. An access point has a range of about 20...
  
   connections, usually with a mounting point or docking station
  Docking station
  A Docking station or port replicator or dock provides a simplified way of “plugging-in” an electronic device such as a laptop computer to common peripherals...
  
   within the vehicle. These can be used as an alternative to MDTs.
• PA
  Public address
  A public address system is an electronic amplification system with a mixer, amplifier and loudspeakers, used to reinforce a sound source, e.g., a person giving a speech, a DJ playing prerecorded music, and distributing the sound throughout a venue or building.Simple PA systems are often used in...
  
   or bullhorn to communicate with other workers, or with members of the public. Most electronic siren
  Siren
  In Greek mythology, the Sirens were three dangerous mermaid like creatures, portrayed as seductresses who lured nearby sailors with their enchanting music and voices to shipwreck on the rocky coast of their island. Roman poets placed them on an island called Sirenum scopuli...
  
  s are equipped with a PA.

Service/unit-specific equipment

Different services require different types of equipment at emergency scenes (ambulances and fire trucks carry different types of equipment), and within one service, different units may require different equipment.

Medical Services

• Ambulance
  Ambulance
  An ambulance is a vehicle for transportation of sick or injured people to, from or between places of treatment for an illness or injury, and in some instances will also provide out of hospital medical care to the patient...
  
  
• Fly car
• Air Ambulance
  Air ambulance
  An air ambulance is an aircraft used for emergency medical assistance in situations where either a traditional ambulance cannot reach the scene easily or quickly enough, or the patient needs to be transported over a distance or terrain that makes air transportation the most practical transport....
  
  

Police

• Armed Response/SWAT
  SWAT
  A SWAT team is an elite tactical unit in various national law enforcement departments. They are trained to perform high-risk operations that fall outside of the abilities of regular officers...
  
   vehicles
• Motorway/Highway Patrol
  Highway patrol
  A highway patrol is either a police unit created primarily for the purpose of overseeing and enforcing traffic safety compliance on roads and highways, or a detail within an existing local or regional police agency that is primarily concerned with such duties.Duties of highway patrols or traffic...
  
   vehicles
• Police Car
  Police car
  A police car is a ground vehicle used by police, to assist with their duties in patrolling and responding to incidents. Typical uses of a police car include transportation for officers to reach the scene of an incident quickly, to transport criminal suspects, or to patrol an area, while providing a...
  
  
• Police Aircraft
  Police aircraft
  A police aircraft is an airplane, helicopter, powered paraglider, or blimpused in police operations. They are commonly used for traffic control, ground support, search and rescue, high-speed car pursuits, observation, air patrol and riot control...
  
  
• Police Motorcycle
  Police motorcycle
  A police motorcycle is a motorcycle used by various police forces and departments. They may be custom designed to meet the requirements unique of a particular use. A police motorcycle is often called a "motor" by police officers in the United States...
  
  
• Police Van
  Police van
  A police van is a type of vehicle operated by police forces. Police vans are usually employed for the transportation of prisoners inside a specially adapted cell in the vehicle, or for the rapid transportation of a number of officers to an incident.- History :Early police vans were in the form of...
  
  

External links

• paper discussing safety equipment on police cars, specifically addressing equipment to address a series of Ford Crown Victorias that suffered rear-end-collisions resulting in fires, and addressing the use of flashing lights, reflectors, &c on police vehicles (PDF file)
• Florida Highway Patrol Lighting and Siren Evaluation
• Ford Announces Development of 2011 Police Interceptor for Law Enforcement