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| There is quite a history behind the modern day LED police lightbar and emergency vehicle lights. Check out the overview that was taken from Wikipedia regarding emergency vehicle lighting. If you would like to view the entire article scroll to the bottom of the page and click on the link. We plan to add other interesting info pertaining to police, fire and EMS vehicle safety. Email us if you know of any articles, studies or any other pertinent information regarding emergency vehicle lighting. Overview Emergency vehicle lighting, light bars and beacons are terms referring to devices designed to make an official vehicle easily identifiable. Emergency vehicle lighting products are fitted to nearly every emergency vehicle and most utility vehicles for the purpose of alerting other vehicles and pedestrians of emergency situations or other road hazards. When an emergency vehicle has the light bar flashing, it signals to drivers and pedestrians that there is an emergency taking place and that every driver needs to make their best attempt to clear the road so that the emergency vehicle can pass safely. When the lights are flashing, it may impose a sense of concern in many drivers which is why many jurisdictions either ban or frown upon the use of emergency lights in non-emergency situations. There are some exceptions however. Police, many times, turn on their emergency lights to protect a driver pulled over for a malfunction in their vehicle or a flat tire. Firefighters may activate their lights when pulling into the station to warn drivers of the engine's presence. There are three main types of emergency vehicle lighting products: single rotating or flashing beacons, larger car roof-sized lightbars, and dashboard or interior lights. Both are effective at drawing attention to a vehicle, but since their inception full-size light bars have increasingly displaced single beacons. Single Beacon Since their introduction in the 1940s, single beacons have become widely accepted as a means of attracting attention to one's vehicle. Although the use of a single beacon in law enforcement has dropped since the introduction of light bars, the single beacon is still used by some police departments because of their lower cost, lower air resistance figures, and in some cases simply due to tradition. One agency that continues to employ a traditional single beacon on their patrol cars is the Michigan State Police. Single beacons may also be seen as secondary lights on a vehicle with a full light bar, either mounted on the vehicles top or inside the vehicle, facing out the windshield or rear window. Beacons are also commonly used on utility and construction vehicles when a full-sized lightbar is ill-suited or impossible to attach to the vehicle. Rotating light These revolving lights usually contain one or several lamps (commonly called light bulbs) around which a curved mirror is spun, creating a rotating beam of light. To protect the workings of the beacon, a plastic dome covers the assembly. These domes usually come in solid colors, but in some cases the front and back halves of the dome are different colors. Other beacons use a clear dome with colored lamps or reflectors inside. Especially in the last case, these rotating beacons have been nicknamed "gumball machines". Omnidirectional Single beacons are now more often available as an omnidirectional strobe light with a translucent dome. Some smaller and low-cost models, however, are simply a flashing halogen bulb. LEDs are also used to light some omnidirectional beacons. Magnet-mount The single beacon is also available with a magnetic mount for situations where permanent mounting is impractical. This can apply to detectives, volunteer firefighters, or managers at freight yards who get a company car but need an amber light for safety. These magnetic-mount beacons are often round or teardrop shaped, and are often referred to as "Kojak" lights after the popular 1970s TV series that used one. Full Size Lightbars Just as the introduction of the single beacon was a great leap forward in vehicle visual warning devices, the practice of using multiple beacons (and thus multiple colors) was a natural progression. In order to utilize two single beacons it became necessary to install a bar across the roof to establish a level platform, and then attach the beacons to this bar, often with a siren speaker and/or "lollipop" lights between the beacons. This was the origin of the term "light bar". The very earliest light bars appeared in the 1960s and were generally custom-built by the agency using them. This was accomplished by fabricating a bar to attach to the vehicle's roof, and then attaching individual components (beacons, lollipops, speakers, oscillating lights, etc.) to the bar. The beacon manufacturers quickly caught on and began producing off-the-shelf complete "light bars". The next progression from the individual component design was to integrate the elements of the lightbar into a single contiguous unit. The colored dome over the beacon was extended toward the center of the bar to accommodate fixed beam lights (in place of lollipops), or one or more mirrors to enhance the flash pattern of the beacon. An enclosure for the siren speaker bridged the gap between the beacon lenses and resulted in the first true contemporary lightbar design. Modern Lightbars Today's modern lightbars combine various elements deemed worthwhile for the specific applications they are applied to. These elements may include: halogen/incandescent rotating lights with or without accompanying mirrors, strobe lights, LED panels, two-tiered (above/below) lights, fixed-beam "takedown" flashing lights, side-facing "alley" spotlights, directional traffic advisory arrows, siren speakers, and more. Several manufacturers have incorporated programmable flash patterns into their lightbars. Some lightbar variations are specialized to meet certain desires of the agency utilizing them, such as those in a "V" shape design which presents additional flash-power to the side of the vehicle, and those designed to hug the roof of a vehicle to minimize air resistance and/or present a lower profile for "stealth" purposes. The modern trend of locating sirens and other audible warning devices at the front of emergency vehicle has also resulted in almost all lightbar models being offered in an "all-light" configuration, with continuous lighting options available across the entire width of the lightbar. Interior Lights A variety of emergency lights are used in the interior of a vehicle, generally on the dashboard, visor area, or rear deck. These are available in a variety of form factors, ranging from flat LED panels under the sun visors, to halogen or strobe lights mounted on the rear deck, to "cherry" or oscillating "teardrop" lights mounted on the dash to interior lightbars. These may be permanently mounted and wired into the vehicle's electrical system, or they may be temporarily mounted and plug into the vehcle's cigarette lighter. Slicktops The aerodynamic properties of light bars can be important for police applications, as fuel efficiency and drag are concerns in patrol and pursuit. Because of this, some police cars do not have roof mounted lightbars. These "slick-top" cars mount their emergency lights within the cruiser, generally around the visor area, dashboard, or rear deck. Some slick-top cars are fitted with lightbars that are built into the leading or trailing edge of the roof, covering the extreme top of the front and/or rear windshields. Slick-top police cars are also noteworthy in that their silhouette lacks the shape of a lightbar or beacon, resembling that of a civilian vehicle and making the car harder to identify as a police vehicle. Because of these visual advantages, these vehicles are often referred to as "stealth" vehicles as opposed to their "marked" counterparts. Wig Wag Many emergency vehicles have alternately flashing "wig-wag" headlights, or have hideaway strobes within their headlights, turn signals, and backup lights. These such setups allow integration of modified OEM equipment and other lighting products. The lights within a lightbar may be halogen, strobe, or LED. Halogen bulbs may be stationary steady or flashing lights, or they may rotate within the lightbar, similarly to the "gumball" lights. Strobe lights can put out 1.5 million candle power for roughly 250 microseconds, while lightbars using halogen bulbs can put out a constant 50,000 to 70,000 candle power. Technologies LED-based lightbars are becoming very popular among many emergency agencies for several reasons. The solid-state LEDs are very efficient and draw less current from the car's battery. Their fast on/off transition time enables attention-grabbing pulses. They have no moving parts and are rated for up to 100,000 hours of use reducing downtime for departments. Finally, LED lightbars can be made very thin to offer less wind resistance. Colors Most people interpret the color of a lightbar to denote the type of vehicle or situation, but the relationship between color and service varies by jurisdiction. In North America the usual emergency colors are red and blue, with blue reserved for police in many jurisdictions. In western Europe the emergency color tends to be only blue, with amber as a warning color for construction equipment etc. In eastern Europe emergency vehicles use blue, or a combination of blue and red. In Asia the usual emergency color is red. Research has shown when flashing lights, twice the amount of blue light energy is needed in daylight to be perceived as bright as red. At night, the situation is reversed.[1] Blue is specific to emergency vehicles only, while red is very common in traffic, in traffic lights, brake lights etc. Source: |
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