Street light
Overview
 
A street light, lamppost, street lamp, light standard, or lamp standard is a raised source of light
Light
Light or visible light is electromagnetic radiation that is visible to the human eye, and is responsible for the sense of sight. Visible light has wavelength in a range from about 380 nanometres to about 740 nm, with a frequency range of about 405 THz to 790 THz...

 on the edge of a road
Road
A road is a thoroughfare, route, or way on land between two places, which typically has been paved or otherwise improved to allow travel by some conveyance, including a horse, cart, or motor vehicle. Roads consist of one, or sometimes two, roadways each with one or more lanes and also any...

 or walkway, which is turned on or lit at a certain time every night. Modern lamps may also have light-sensitive photocells to turn them on at dusk
Dusk
Dusk is the beginning of darkness in the evening, and occurs after twilight, when the sky generally remains bright and blue. Civil dusk is when the earth has rotated enough that the center of the sun is at 6° below the local horizon...

, off at dawn
Dawn
Dawn is the time that marks the beginning of the twilight before sunrise. It is recognized by the presence of weak sunlight, while the sun itself is still below the horizon...

, or activate automatically in dark weather
Weather
Weather is the state of the atmosphere, to the degree that it is hot or cold, wet or dry, calm or stormy, clear or cloudy. Most weather phenomena occur in the troposphere, just below the stratosphere. Weather refers, generally, to day-to-day temperature and precipitation activity, whereas climate...

. In older lighting this function would have been performed with the aid of a solar dial
Solar dial
A solar dial is type of time switch used primarily for controlling lighting. They were/are primarily manufactured by the companies Venner, Horstmann and Sangamo.-Benefits:...

.
Encyclopedia
A street light, lamppost, street lamp, light standard, or lamp standard is a raised source of light
Light
Light or visible light is electromagnetic radiation that is visible to the human eye, and is responsible for the sense of sight. Visible light has wavelength in a range from about 380 nanometres to about 740 nm, with a frequency range of about 405 THz to 790 THz...

 on the edge of a road
Road
A road is a thoroughfare, route, or way on land between two places, which typically has been paved or otherwise improved to allow travel by some conveyance, including a horse, cart, or motor vehicle. Roads consist of one, or sometimes two, roadways each with one or more lanes and also any...

 or walkway, which is turned on or lit at a certain time every night. Modern lamps may also have light-sensitive photocells to turn them on at dusk
Dusk
Dusk is the beginning of darkness in the evening, and occurs after twilight, when the sky generally remains bright and blue. Civil dusk is when the earth has rotated enough that the center of the sun is at 6° below the local horizon...

, off at dawn
Dawn
Dawn is the time that marks the beginning of the twilight before sunrise. It is recognized by the presence of weak sunlight, while the sun itself is still below the horizon...

, or activate automatically in dark weather
Weather
Weather is the state of the atmosphere, to the degree that it is hot or cold, wet or dry, calm or stormy, clear or cloudy. Most weather phenomena occur in the troposphere, just below the stratosphere. Weather refers, generally, to day-to-day temperature and precipitation activity, whereas climate...

. In older lighting this function would have been performed with the aid of a solar dial
Solar dial
A solar dial is type of time switch used primarily for controlling lighting. They were/are primarily manufactured by the companies Venner, Horstmann and Sangamo.-Benefits:...

. It is not uncommon for street lights to be on posts which have wires strung between them, such as on telephone poles or utility pole
Utility pole
A utility pole is a pole used to support overhead power lines and various other public utilities, such as cable, fibre optic cable, and related equipment such as transformers and street lights. It can be referred to as a telephone pole, power pole, hydro pole, telegraph pole, or telegraph post,...

s.

History

The earliest lamps were used by Greek and Roman civilizations, where light primarily served the purpose of security, both to protect the wanderer from tripping over something on the path as well as keeping the potential robbers at bay. At that time oil lamps were used predominantly as they provided a long-lasting and moderate flame. The Romans had a word 'laternarius', which was a term for a slave responsible for lighting up the oil lamps in front of their villas. This task continued to be kept for a special person as far as up to Middle Ages where the so-called 'link boys' escorted people from one place to another through the murky winding streets of medieval towns.

Before incandescent
Incandescence
Incandescence is the emission of light from a hot body as a result of its temperature. The term derives from the Latin verb incandescere, to glow white....

 lamps, gas lighting
Gas lighting
Gas lighting is production of artificial light from combustion of a gaseous fuel, including hydrogen, methane, carbon monoxide, propane, butane, acetylene, ethylene, or natural gas. Before electricity became sufficiently widespread and economical to allow for general public use, gas was the most...

 was employed in cities. The earliest lamps required that a lamplighter
Lamplighter
A lamplighter, historically, was an employee of a town who lit street lights, generally by means of a wick on a long pole. At dawn, they would return and extinguish them using a small hook on the same pole. Early street lights were generally candles, oil, and similar consumable liquid or solid...

 tour the town at dusk, lighting each of the lamps, but later designs employed ignition devices that would automatically strike the flame when the gas supply was activated. The earliest of such street lamps were built in the Arab Empire
Caliphate of Córdoba
The Caliphate of Córdoba ruled the Iberian peninsula and part of North Africa, from the city of Córdoba, from 929 to 1031. This period was characterized by remarkable success in trade and culture; many of the masterpieces of Islamic Iberia were constructed in this period, including the famous...

, especially in Córdoba, Spain
Córdoba, Spain
-History:The first trace of human presence in the area are remains of a Neanderthal Man, dating to c. 32,000 BC. In the 8th century BC, during the ancient Tartessos period, a pre-urban settlement existed. The population gradually learned copper and silver metallurgy...

 ( around 1000 CE/AD ). The first modern street lamps, which used kerosene, were introduced in Lviv
Lviv
Lviv is a city in western Ukraine. The city is regarded as one of the main cultural centres of today's Ukraine and historically has also been a major Polish and Jewish cultural center, as Poles and Jews were the two main ethnicities of the city until the outbreak of World War II and the following...

 in what was then the Austrian Empire
Austrian Empire
The Austrian Empire was a modern era successor empire, which was centered on what is today's Austria and which officially lasted from 1804 to 1867. It was followed by the Empire of Austria-Hungary, whose proclamation was a diplomatic move that elevated Hungary's status within the Austrian Empire...

 in 1853.

The first electric street lighting employed arc lamps, initially the 'Electric candle', 'Jablotchkoff candle' or 'Yablochkov candle
Yablochkov candle
A Yablochkov candle is a type of electric carbon arc lamp, invented in 1876 by Pavel Yablochkov.-Design:A Yablochkov candle consists of a sandwich of two long carbon blocks, approximately 6 by 12 millimetres in cross-section, separated by a block of inert material such as plaster of paris or kaolin...

' developed by the Russian Pavel Yablochkov
Pavel Yablochkov
Pavel Nikolayevich Yablochkov was a Russian electrical engineer, the inventor of the Yablochkov candle and businessman.-Biography:...

 in 1875. This was a carbon arc lamp employing alternating current, which ensured that both electrodes were consumed at equal rates. Yablochkov candles were first used to light the Grands Magasins du Louvre
Grands Magasins du Louvre
Les Grands Magasins du Louvre, initially Les Galeries du Louvre, a department store in Paris, France, was founded in 1855, three years after its competitor, Le Bon Marché. Under new management as the Société du Louvre, it closed definitively in 1974. At present, the building houses the Louvre des...

, Paris
Paris
Paris is the capital and largest city in France, situated on the river Seine, in northern France, at the heart of the Île-de-France region...

 where 80 were deployed—improvement which was one of the reasons why Paris earned its "City of Lights" nickname. Soon after, experimental arrays of arc lamps were used to light Holborn Viaduct
Holborn Viaduct
Holborn Viaduct is a bridge in London and the name of the street which crosses it . It links Holborn, via Holborn Circus, with Newgate Street in the City of London, passing over Farringdon Street and the now subterranean River Fleet.It was built between 1863 and 1869, at a cost of over two million...

 and the Thames Embankment
Thames Embankment
The Thames Embankment is a major feat of 19th century civil engineering designed to reclaim marshy land next to the River Thames in central London. It consists of the Victoria and Chelsea Embankment....

 in London
London
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...

 - the first electric street lighting in Britain. More than 4,000 were in use by 1881, though by then an improved differential arc lamp had been developed by Friedrich von Hefner-Alteneck
Friedrich von Hefner-Alteneck
Friedrich Heinrich Philipp Franz von Hefner-Alteneck was a German electrical engineer and one of the closest aides of Werner von Siemens. He is largely remembered for the invention of the Hefner lamp, which provided the measure of luminous intensity used in Germany, Austria and Scandinavia from...

 of Siemens & Halske
Siemens & Halske
Siemens & Halske AG was a German electrical engineering company that later became part of Siemens AG.It was founded on 12 October 1847 as Telegraphen-Bauanstalt von Siemens & Halske by Ernst Werner von Siemens and Johann Georg Halske...

. The United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 was swift in adopting arc lighting, and by 1890 over 130,000 were in operation in the US, commonly installed in exceptionally tall moonlight tower
Moonlight tower
Moonlight towers are lighting structures designed to illuminate areas of a city at night.The structures were popular in the late 19th century in cities across the United States and Europe; they were most common in the 1880s-1890s...

s.

The first street in the UK to be lit by electric light was Mosley Street, in Newcastle-upon-Tyne. The street was lit by Joseph Swan's incandescent lamp on the 3rd February, 1879. The first in the United States, and second overall, was the Public Square
Public Square
Public Square is the central plaza in downtown Cleveland, Ohio, United States. It takes up four city blocks; Superior Avenue and Ontario Street cross through it. Cleveland's three tallest buildings, Key Tower, 200 Public Square and the Terminal Tower, face the square...

 road system in Cleveland, Ohio
Cleveland, Ohio
Cleveland is a city in the U.S. state of Ohio and is the county seat of Cuyahoga County, the most populous county in the state. The city is located in northeastern Ohio on the southern shore of Lake Erie, approximately west of the Pennsylvania border...

, on April 29, 1879. Wabash, Indiana
Wabash, Indiana
Wabash is a city in Noble Township, Wabash County, Indiana, United States. The population was 10,666 at the 2010 census. The city is the county seat of Wabash County....

 holds the title of being the third electrically-lit city in the world, which took place on February 2, 1880. Four 3,000 candlepower Brush arc lamps suspended over the courthouse rendered the town square "as light as midday." Kimberley
Kimberley, Northern Cape
Kimberley is a city in South Africa, and the capital of the Northern Cape. It is located near the confluence of the Vaal and Orange Rivers. The town has considerable historical significance due its diamond mining past and siege during the Second Boer War...

, South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...

, was the first city in the Southern Hemisphere
Southern Hemisphere
The Southern Hemisphere is the part of Earth that lies south of the equator. The word hemisphere literally means 'half ball' or "half sphere"...

 and in Africa
Africa
Africa is the world's second largest and second most populous continent, after Asia. At about 30.2 million km² including adjacent islands, it covers 6% of the Earth's total surface area and 20.4% of the total land area...

 to have electric street lights - first lit on 1 September 1882 . In Latin America, San Jose
San José, Costa Rica
San José is the capital and largest city of Costa Rica. Located in the Central Valley, San José is the seat of national government, the focal point of political and economic activity, and the major transportation hub of this Central American nation.Founded in 1738 by order of Cabildo de León, San...

, Costa Rica
Costa Rica
Costa Rica , officially the Republic of Costa Rica is a multilingual, multiethnic and multicultural country in Central America, bordered by Nicaragua to the north, Panama to the southeast, the Pacific Ocean to the west and the Caribbean Sea to the east....

 was the first city, the system was launched on August 9, 1884, with 25 lamps powered by an hydroelectric plant. Timişoara
Timisoara
Timișoara is the capital city of Timiș County, in western Romania. One of the largest Romanian cities, with an estimated population of 311,586 inhabitants , and considered the informal capital city of the historical region of Banat, Timișoara is the main social, economic and cultural center in the...

, in present-day Romania
Romania
Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...

, was the first city in mainland Europe to have electric public lighting on the 12 of November 1884. 731 lamps were used. In 1888 Tamworth
Tamworth, New South Wales
Tamworth is a city in the New England region of New South Wales, Australia. Straddling the Peel River, Tamworth, which contains an estimated population of 47,595 people, is the major regional centre for southern New England and in the local government area of Tamworth Regional Council. The city...

, New South Wales
New South Wales
New South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...

, Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

 became the first location in Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

 to have electric street lighting, giving the city the title of "First City of Light".

Arc lights had two major disadvantages. First, they emit an intense and harsh light which, although useful at industrial sites like dockyards, was discomforting in ordinary city streets. Second, they are maintenance-intensive, as carbon electrodes burn away swiftly. With the development of cheap, reliable and bright incandescent light bulb
Incandescent light bulb
The incandescent light bulb, incandescent lamp or incandescent light globe makes light by heating a metal filament wire to a high temperature until it glows. The hot filament is protected from air by a glass bulb that is filled with inert gas or evacuated. In a halogen lamp, a chemical process...

s at the end of the 19th century, arc lights passed out of use for street lighting, but remained in industrial use longer.

Incandescent lamps were primarily used for street lighting until the advent of high-intensity discharge lamps. They were often operated at high-voltage series circuits. Series circuits were popular since the higher voltage in these circuits produced more light per watt consumed. Furthermore, before the invention of photoelectric controls, a single switch or clock could control all the lights in an entire district.

To avoid having the entire system go dark if a single lamp burned out, each street lamp was equipped with a device that ensured that the circuit would remain intact. Early series street lights were equipped with isolation transformers. that would allow current to pass across the transformer whether the bulb worked or not. Later the film cutout was invented. The film cutout was a small disk of insulating film that separated two contacts connected to the two wires leading to the lamp. If the lamp failed (an open circuit
Open-circuit voltage
Open-circuit voltage is the difference of electrical potential between two terminals of a device when there is no external load connected, i.e. the circuit is broken or open. Under these conditions there is no external electric current between the terminals, even though there may be current...

), the current through the string became zero, causing the voltage of the circuit (thousands of volts) to be imposed across the insulating film, penetrating it (see Ohm's law
Ohm's law
Ohm's law states that the current through a conductor between two points is directly proportional to the potential difference across the two points...

). In this way, the failed lamp was bypassed and power restored to the rest of the district. The street light circuit contained an automatic voltage regulator, preventing the current from increasing as lamps burned out, preserving the life of the remaining lamps. When the failed lamp was replaced, a new piece of film was installed, once again separating the contacts in the cutout. This system was recognizable by the large porcelain
Porcelain
Porcelain is a ceramic material made by heating raw materials, generally including clay in the form of kaolin, in a kiln to temperatures between and...

 insulator separating the lamp and reflector from the mounting arm. This was necessary because the two contacts in the lamp's base may have operated at several thousand volts above ground/earth.

Today, street lighting commonly uses high-intensity discharge lamp
High-intensity discharge lamp
High-intensity discharge lamps are a type of electrical lamp which produces light by means of an electric arc between tungsten electrodes housed inside a translucent or transparent fused quartz or fused alumina arc tube. This tube is filled with both gas and metal salts. The gas facilitates the...

s, often HPS high pressure sodium lamps. Such lamps provide the greatest amount of photopic illumination for the least consumption of electricity. However when scotopic/photopic light calculations are used, it can been seen how inappropriate HPS lamps are for night lighting. White light sources have been shown to double driver peripheral vision and increase driver brake reaction time at least 25%. When S/P light calculations are used, HPS lamp performance needs to be reduced by a minimum value of 75%. This is now a standard design criteria for Australian roads.

A study comparing metal halide and high-pressure sodium lamps showed that at equal photopic light levels, a street scene illuminated at night by a metal halide lighting system was reliably seen as brighter and safer than the same scene illuminated by a high pressure sodium system.

New street lighting technologies, such as LED
LEd
LEd is a TeX/LaTeX editing software working under Microsoft Windows. It is a freeware product....

 or induction
Induction
-General use:* Induction , induction of childbirth* Rite of passage** Introduction of an individual into a body such as the armed forces** Formal introduction of a priest into possession of the position to which she or he has been presented and instituted...

lights, emit a white light that provides high levels of scotopic lumens allowing street lights with lower wattages and lower photopic lumens to replace existing street lights. However, there have been no formal specifications written around Photopic/Scotopic adjustments for different types of light sources, causing many municipalities and street departments to hold back on implementation of these new technologies until the standards are updated.

Photovoltaic-powered LED luminaires are gaining wider acceptance. Preliminary field tests show that some LED luminaires are energy-efficient and perform well in testing environments.

In 2007, the Civil Twilight Collective created a variant of the conventional LED streetlight, namely the Lunar-resonant streetlight. These lights increase or decrease the intensity of the streetlight according to the lunar
Moon
The Moon is Earth's only known natural satellite,There are a number of near-Earth asteroids including 3753 Cruithne that are co-orbital with Earth: their orbits bring them close to Earth for periods of time but then alter in the long term . These are quasi-satellites and not true moons. For more...

 light. This streetlight design thus reduces energy consumption as well as light pollution.

Measurement

Two very similar measurement systems were created to bridge the scotopic and photopic luminous efficiency functions, creating a Unified System of Photometry. This new measurement has been well-received because the reliance on V(λ) alone for characterizing night-time light illuminations requires more electric energy. The cost-savings potential of using a new way to measure mesopic lighting scenarios is tremendous.

Outdoor Site-Lighting Performance (OSP) is a method for predicting and measuring three different aspects of light pollution: glow, trespass and glare. Using this method, lighting specifiers can quantify the performance of existing and planned lighting designs and applications to minimize excessive or obtrusive light leaving the boundaries of a property.

Advantages

Major advantages of street lighting includes: prevention of accidents and increase in safety. Studies have shown that darkness results in a large number of crashes and fatalities, especially those involving pedestrians; pedestrian fatalities are 3 to 6.75 times more likely in the dark than in daylight. Street lighting has been found to reduce pedestrian crashes by approximately 50%.

Furthermore, lighted intersections and highway interchanges tend to have fewer crashes than unlighted intersections and interchanges.

Towns, cities, and villages use the unique locations provided by light poles to hang decorative or commemorative banners.

Disadvantages

The major criticisms of street lighting are that it can actually cause accidents if misused, and cause light pollution
Light pollution
Light pollution, also known as photopollution or luminous pollution, is excessive or obtrusive artificial light.The International Dark-Sky Association defines light pollution as:...

.

Dangers

There are two optical phenomena that need to be recognized in street light installations.
  • The loss of night vision
    Night vision
    Night vision is the ability to see in low light conditions. Whether by biological or technological means, night vision is made possible by a combination of two approaches: sufficient spectral range, and sufficient intensity range...

     because of the accommodation reflex
    Accommodation reflex
    The accommodation reflex is a reflex action of the eye, in response to focusing on a near object, then looking at distant object , comprising coordinated changes in vergence, lens shape and pupil size...

     of drivers' eyes is the greatest danger. As drivers emerge from an unlighted area into a pool of light from a street light their pupil
    Pupil
    The pupil is a hole located in the center of the iris of the eye that allows light to enter the retina. It appears black because most of the light entering the pupil is absorbed by the tissues inside the eye. In humans the pupil is round, but other species, such as some cats, have slit pupils. In...

    s quickly constrict to adjust to the brighter light, but as they leave the pool of light the dilation of their pupils to adjust to the dimmer light is much slower, so they are driving with impaired vision. As a person gets older the eye's recovery speed gets slower, so driving time and distance under impaired vision increases.

  • Oncoming headlights are more visible against a black background than a grey one. The contrast creates greater awareness of the oncoming vehicle.

  • Stray voltage
    Stray voltage
    Stray voltage describes the occurrence of electrical potential between two objects that ideally should not have any voltage difference between them. Small voltages are often measured between two grounded objects in distant locations, due to normal current flow in the power system...

     is also a concern in many cities. Stray voltage can accidentally electrify light poles and has the potential to injure or kill anyone who comes into contact with the pole. Some cities have employed the Electrified Cover Safeguard(TM) technology which sounds an alarm and flashes a light, to warn the public, when a pole becomes dangerously electrified.


There are also physical dangers. Street light stanchions (poles) pose a collision risk to motorists. This can be reduced by designing them to break away when hit (frangible
Frangible
A material is said to be frangible if through deformation it tends to break up into fragments, rather than deforming plastically and retaining its cohesion as a single object...

 or collapsible supports), protecting them by guardrails, or marking the lower portions to increase their visibility. High winds or accumulated metal fatigue
Fatigue (material)
'In materials science, fatigue is the progressive and localized structural damage that occurs when a material is subjected to cyclic loading. The nominal maximum stress values are less than the ultimate tensile stress limit, and may be below the yield stress limit of the material.Fatigue occurs...

 also occasionally topple street lights.

Light pollution

In urban areas light pollution
Light pollution
Light pollution, also known as photopollution or luminous pollution, is excessive or obtrusive artificial light.The International Dark-Sky Association defines light pollution as:...

 can hide the stars and interfere with astronomy
Astronomy
Astronomy is a natural science that deals with the study of celestial objects and phenomena that originate outside the atmosphere of Earth...

. In settings near astronomical telescope
Telescope
A telescope is an instrument that aids in the observation of remote objects by collecting electromagnetic radiation . The first known practical telescopes were invented in the Netherlands at the beginning of the 1600s , using glass lenses...

s and observatories
Observatory
An observatory is a location used for observing terrestrial or celestial events. Astronomy, climatology/meteorology, geology, oceanography and volcanology are examples of disciplines for which observatories have been constructed...

, low pressure sodium
Sodium
Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...

 lamps may be used. These lamps are advantageous over other lamps such as mercury
Mercury (element)
Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...

 and metal halide lamps because low pressure sodium lamps emit lower intensity, monochromatic light. Observatories can filter the sodium wavelength
Wavelength
In physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the wave's shape repeats.It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a...

 out of their observations and virtually eliminate the interference from nearby urban lighting. Full cutoff streetlights also reduce light pollution by reducing the amount of light that is directed at the sky which also improves the luminous efficiency of the light.

Purpose

There are three distinct main uses of street lights, each requiring different types of lights and placement. Misuse of the different types of lights can make the situation worse by compromising visibility or safety.

Beacon lights

A modest steady light at the intersection of two roads is an aid to navigation because it helps a driver see the location of a side road as they come closer to it and they can adjust their braking and know exactly where to turn if they intend to leave the main road or see vehicles or pedestrians. A beacon light's function is to say "here I am" and even a dim light provides enough contrast against the dark night to serve the purpose. To prevent the dangers caused by a car driving through a pool of light, a beacon light must never shine onto the main road, and not brightly onto the side road. In residential areas, this is usually the only appropriate lighting, and it has the bonus side effect of providing spill lighting onto any sidewalk there for the benefit of pedestrians. On Interstate highways this purpose is commonly served by placing reflectors at the sides of the road.

Roadway lights

Street lights are not normally intended to illuminate the driving route (headlights are preferred), but to reveal signs and hazards outside of the headlights' beam. Because of the dangers discussed above, roadway lights are properly used sparingly and only when a particular situation justifies increasing the risk. This usually involves an intersection with several turning movements and much signage, situations where drivers must take in much information quickly that is not in the headlights' beam. In these situations (A freeway junction or exit ramp) the intersection may be lit so that drivers can quickly see all hazards, and a well designed plan will have gradually increasing lighting for approximately a quarter of a minute before the intersection and gradually decreasing lighting after it. The main stretches of highways remain unlighted to preserve the driver's night vision and increase the visibility of oncoming headlights. If there is a sharp curve where headlights will not illuminate the road, a light on the outside of the curve is often justified.

If it is desired to light a roadway (perhaps due to heavy and fast multi-lane traffic), to avoid the dangers of casual placement of street lights it should not be lit intermittently, as this requires repeated eye readjustment which implies eyestrain
Asthenopia
Asthenopia or eye strain is an ophthalmological condition that manifests itself through nonspecific symptoms such as fatigue, pain in or around the eyes, blurred vision, headache and occasional double vision...

 and temporary blindness when entering and leaving light pools. In this case the system is designed to eliminate the need for headlights. This is usually achieved with bright lights placed on high poles at close regular intervals so that there is consistent light along the route. The lighting goes from curb to curb.

For more information, see the lighting section of "Pedestrian Crossings"
Pedestrian crossing
A pedestrian crossing or crosswalk is a designated point on a road at which some means are employed to assist pedestrians wishing to cross. They are designed to keep pedestrians together where they can be seen by motorists, and where they can cross most safely across the flow of vehicular traffic...

 article.

Security lighting

Security lighting
Security lighting
In the field of physical security, security lighting is often used as a preventative and corrective measure against intrusions or other criminal activity on a physical piece of property. Security lighting may be provided to aid in the detection of intruders, to deter intruders, or in some cases...

 is similar to high-intensity lighting on a busy major street, with no pools of light and dark, but with the lighted area extending onto people's property, at least to their front door. This requires a different type of fixture and lens
Lens (optics)
A lens is an optical device with perfect or approximate axial symmetry which transmits and refracts light, converging or diverging the beam. A simple lens consists of a single optical element...

. The increased glare experienced by drivers going through the area might be considered a trade-off for increased security. This is what would normally be used along sidewalks in dense areas of cities.

Street light control systems

A number of street light control systems have been developed to control and reduce energy consumption of a town's public lighting system. These range from controlling a circuit of street lights and/or individual lights with specific ballasts and network operating protocols. These may include sending and receiving instructions via separate data networks,at high frequency over the top of the low voltage supply or wireless. Various protocols have been developed as well as compatible hardware for most types of lighting.

Main manufacturers

Australia
  • GEC (General Electric
    General Electric
    General Electric Company , or GE, is an American multinational conglomerate corporation incorporated in Schenectady, New York and headquartered in Fairfield, Connecticut, United States...

    )
  • Osram Sylvania
    Osram Sylvania
    Osram Sylvania Inc. is the North American operation of lighting manufacturer Osram GmbH, which is owned by Siemens AG. It was established in January 1993, with the acquisition of GTE’s Sylvania lighting division by Osram GmbH....

  • Philips
    Philips
    Koninklijke Philips Electronics N.V. , more commonly known as Philips, is a multinational Dutch electronics company....

  • Rexel
    Rexel
    Rexel is a French group founded in 1967. It is specialised in the professional distribution of electrical supplies. The solutions offered by Rexel cover a wide range of equipment, including lighting, security, automation, climate control, communication, building automation and renewable energies....

  • Thorn Lighting
    Zumtobel Lighting Group
    Zumtobel Group is a company based in Dornbirn, Austria which comprises two sub-groups: Zumtobel Lighting Group, which includes the lighting brands "Zumtobel" and "Thorn"; and Tridonic, which manufactures lighting components...

  • Westinghouse


Americas
  • American Electric Lighting (formerly ITT
    ITT Corporation
    ITT Corporation is a global diversified manufacturing company based in the United States. ITT participates in global markets including water and fluids management, defense and security, and motion and flow control...

    , later Thomas & Betts
    Thomas & Betts
    Thomas & Betts is a designer and manufacturer of connectors and components for electrical and communication markets. Thomas & Betts is notable as the inventor of cable ties in 1958...

    )
  • Cooper Lighting division of Cooper Industries
    Cooper Industries
    Cooper Industries is a former US-based company that in 2009 switched its incorporation office from Bermuda to Ireland, maintaining its chief operational offices in Houston, Texas. It produces transformers, tools and electrical equipment, employing 29,000 staff around the world. Revenue in 2007 was...

  • General Electric
    General Electric
    General Electric Company , or GE, is an American multinational conglomerate corporation incorporated in Schenectady, New York and headquartered in Fairfield, Connecticut, United States...

    , USA.
  • Osram Sylvania
    Osram Sylvania
    Osram Sylvania Inc. is the North American operation of lighting manufacturer Osram GmbH, which is owned by Siemens AG. It was established in January 1993, with the acquisition of GTE’s Sylvania lighting division by Osram GmbH....

  • Westinghouse Lighting Corporation (formerly Angelo Brothers) division of the new Westinghouse Electric
    Westinghouse Electric (1998)
    Westinghouse Licensing, doing business as Westinghouse Electric Corporation , is a Delaware General Corporation Law organized subsidiary that was founded by CBS Corporation in managing the intellectual property assets relating to the Westinghouse trademarks.Westinghouse Licensing has...


Europe
  • Osram
    Osram
    Osram, founded 1919, is part of the industry sector of Siemens AG and one of the two leading lighting manufacturers in the world. The name is derived from osmium and Wolfram , as both these elements were commonly used for lighting filaments at the time the company was founded...

    , Germany.
  • Philips
    Philips
    Koninklijke Philips Electronics N.V. , more commonly known as Philips, is a multinational Dutch electronics company....

    , the Netherlands.
  • Siemens
    Siemens
    Siemens may refer toSiemens, a German family name carried by generations of telecommunications industrialists, including:* Werner von Siemens , inventor, founder of Siemens AG...

    , Germany.
  • Svetlina AD
    Svetlina AD
    Svetlina AD, or more commonly only Svetlina is the name of two Bulgarian lighting manufacturing plants. The word svetlina means light and AD is a similar abbreviation to the French s.a. or English Ltd.- Svetlina AD :...

    , Bulgaria.
  • Tungsram
    Tungsram
    Tungsram is a Hungarian manufacturer of light bulbs and vacuum tubes since 1896. General Electric, in 1990, acquired majority share in one of Hungary's largest, oldest, and internationally most prestigious firms, the light-source manufacturer Tungsram. Over the past six years GE has invested $600...

    , Hungary.
  • Calzavara, Italy.
  • GEC, United Kingdom.
  • Philips
    Philips
    Koninklijke Philips Electronics N.V. , more commonly known as Philips, is a multinational Dutch electronics company....

    , United Kingdom.
  • Thorn Lighting, United Kingdom.


Asia
  • Matsushita Electric Industrial Co., Japan
  • Sanyo
    Sanyo
    is a major electronics company and member of the Fortune 500 whose headquarters is located in Moriguchi, Osaka prefecture, Japan. Sanyo targets the middle of the market and has over 230 Subsidiaries and Affiliates....

    , Japan

See also

  • Charging station
    Charging station
    An electric vehicle charging station, also called EV charging station, electric recharging point, charging point and EVSE , is an element in an infrastructure that supplies electric energy for the recharging of electric vehicles, plug-in hybrid electric-gasoline vehicles) or semi-static and mobile...

  • Gas lighting
    Gas lighting
    Gas lighting is production of artificial light from combustion of a gaseous fuel, including hydrogen, methane, carbon monoxide, propane, butane, acetylene, ethylene, or natural gas. Before electricity became sufficiently widespread and economical to allow for general public use, gas was the most...

  • History of street lighting in the United States
    History of street lighting in the United States
    The use of street lighting was first recorded in the city of Antioch from the 4th century, later in the Arab Empire from the 9th–10th centuries, especially in Cordova, and then in London from 1417 when Henry Barton, the mayor, ordered "lanterns with lights to be hanged out on the winter evenings...

  • Lighting-up time
    Lighting-up time
    In the United Kingdom there is a legally enforced lighting-up time, defined as from one half-hour after sunset to one half-hour before sunrise, during which all motor vehicles on unlit public roads must use their headlights....

  • List of light sources
  • Solar lamp
    Solar lamp
    A solar lamp is a portable light fixture composed of a LED lamp, a photovoltaic solar panel, and a rechargeable battery.Outdoor lamps are used for lawn and garden decorations. Indoor solar lamps are also used for general illumination .Solar lights are used for decoration, and come in a wide variety...

  • Street light interference
    Street Light Interference
    Street light interference, or SLI, is an alleged anomalous phenomenon where a person seems to turn off street lights, or outside building security lights, when passing near them....

  • Street furniture
    Street furniture
    Street furniture is a collective term for objects and pieces of equipment installed on streets and roads for various purposes, including traffic barriers,...


External links

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