History of street lighting in the United States
Encyclopedia
The use of street light
Street light
A street light, lamppost, street lamp, light standard, or lamp standard is a raised source of light on the edge of a road 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, off at dawn, or activate...

ing
was first recorded in the city of Antioch
Antioch
Antioch on the Orontes was an ancient city on the eastern side of the Orontes River. It is near the modern city of Antakya, Turkey.Founded near the end of the 4th century BC by Seleucus I Nicator, one of Alexander the Great's generals, Antioch eventually rivaled Alexandria as the chief city of the...

 from the 4th century, later 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...

 from the 9th–10th centuries, especially in Cordova
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...

, and then in London from 1417 when Henry Barton
Henry Barton
Henry Barton was appointed Sheriff of London in 1406 and elected Lord Mayor of London in 1416....

, the mayor, ordered "lanterns with lights to be hanged out on the winter evenings between Hallowtide
All Saints
All Saints' Day , often shortened to All Saints, is a solemnity celebrated on 1 November by parts of Western Christianity, and on the first Sunday after Pentecost in Eastern Christianity, in honour of all the saints, known and unknown...

 and Candlemasse." However it was introduced to the United States by famed inventor Benjamin Franklin
Benjamin Franklin
Dr. Benjamin Franklin was one of the Founding Fathers of the United States. A noted polymath, Franklin was a leading author, printer, political theorist, politician, postmaster, scientist, musician, inventor, satirist, civic activist, statesman, and diplomat...

, who was the postmaster of Philadelphia
Philadelphia, Pennsylvania
Philadelphia is the largest city in the Commonwealth of Pennsylvania and the county seat of Philadelphia County, with which it is coterminous. The city is located in the Northeastern United States along the Delaware and Schuylkill rivers. It is the fifth-most-populous city in the United States,...

, Pennsylvania. Because of this, many regard Philadelphia as the birthplace of street lighting in the United States.

The colonial-era streetlights were lit by candles placed inside a glass vessel, which kept the candle from being blown out by wind. Franklin's design was four-sided, with four separate panes of glass, so that if one pane of glass was broken, the lamp did not need to be entirely replaced, and might not even blow out.

After the invention of gas light
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...

 by William Murdoch
William Murdoch
William Murdoch was a Scottish engineer and long-term inventor.Murdoch was employed by the firm of Boulton and Watt and worked for them in Cornwall, as a steam engine erector for ten years, spending most of the rest of his life in Birmingham, England.He was the inventor of the oscillating steam...

 in 1792, cities in Britain began to light their streets using gas. The United States followed suit shortly afterwards with the introduction of gas lighting to the streets of Baltimore
Baltimore
Baltimore is the largest independent city in the United States and the largest city and cultural center of the US state of Maryland. The city is located in central Maryland along the tidal portion of the Patapsco River, an arm of the Chesapeake Bay. Baltimore is sometimes referred to as Baltimore...

 in 1816. Throughout the nineteenth century, the use of gas lighting increased. Some locations in the United States still use gas lights; see 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...

.

After Edison
Thomas Edison
Thomas Alva Edison was an American inventor and businessman. He developed many devices that greatly influenced life around the world, including the phonograph, the motion picture camera, and a long-lasting, practical electric light bulb. In addition, he created the world’s first industrial...

 pioneered electric use, light bulbs were developed for the streetlights as well. The first city to use electric street lights was Wabash, Indiana. Charles F. Brush of Cleveland, Ohio wanted to publicly test his new invention the "Brush Light" and needed a city to do so. The City Council of Wabash agreed to testing the lights and on March 31, 1880, Wabash became the "First Electrically Lighted City in the World" as a flood of light engulfed the town from four Brush Lights mounted on top of the courthouse. People can still see one of the original Brush Lights on display at the Wabash County Courthouse. By the beginning of the 20th century, the number of fire-based streetlights was dwindling as developers were searching for safer and more effective ways to illuminate their streets. Fluorescent and incandescent lights became very popular during the 1930s and 1940s, when automobile travel began to flourish. A street with lights was referred to as a white way during the early 20th century; part of New York City's Broadway
Broadway (New York City)
Broadway is a prominent avenue in New York City, United States, which runs through the full length of the borough of Manhattan and continues northward through the Bronx borough before terminating in Westchester County, New York. It is the oldest north–south main thoroughfare in the city, dating to...

 was nicknamed the Great White Way due to the massive number of electric lights used on theater marquees lining the street.

History of manufacturers

The two main competitors in the street lighting industry were 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...

 and Westinghouse. During the 1950s, GE lit roadways with its Form 109 and, later, the wildly popular Form 400. Westinghouse answered with the OV-20 model.

In 1957, a new breed of streetlight fixture was introduced. These fixtures were called "cobraheads". If viewed from beneath they resembled a cobra
Cobra
Cobra is a venomous snake belonging to the family Elapidae. However, not all snakes commonly referred to as cobras are of the same genus, or even of the same family. The name is short for cobra capo or capa Snake, which is Portuguese for "snake with hood", or "hood-snake"...

's flared neck. Westinghouse dubbed its cobraheads the Silverliners, which remained in production over the next 25 years. The OV-25 remains a very popular and most-beloved streetlight fixture.

GE later came out with its own cobrahead, called the M400. The original M400 is noted for its pointed front end that protrudes over its bowl-shaped diffuser (also called a refractor). The M400 was the OV-25's main rival. They carried 250–400 watt bulbs, and therefore, were common on Interstate highways and city boulevards. GE made the M250 which was exactly same design as the M400 but using plastic refractor made for 250 watt. The M250 production ended in 1960 replacing with a M250R.

In 1964, Westinghouse produced an updated version of the OV-25, with a more rounded look. Only the diffuser was left unchanged.

In 1967, GE updated its M400 and M250 with its PowrDoor design. Gone was the protruding front end, and the new M400A and M250A were also more streamlined (although the original M400 and M250R continued to be produced until 1970). In 1970, a split-door M400 was introduced that shared the M400A's bodyshell but had a nonvented door held in place with a spring latch, while the M400A's vented door was held in place with a bail latch.

GE and Westinghouse also developed smaller fixtures. A miniature version of the M400 was made for suburban residential streets and alleys. That fixture was called the M250R which replaced the M250 which looked exactly like the M400 but with plastic lens and rated for 250 watt. In the same vein, Westinghouse offered three smaller Silverliners. The OV-12 (whose look resembles a miniature OV-50) came out in 1960, and it became the companion model to the Canadian-market OV-14B, which had been introduced in 1957. The OV-14B looks like a smaller version of the 1957-edition OV-25. Both the OV-12 and OV-14B were replaced by the OV-15 in 1965. These smaller fixtures carried 100–250 watt light bulbs.

The second-generation M400 and M250 were the first fixtures to sport the new high pressure sodium (HPS) lights that came out in 1970. The existing Silverliners could not handle these new lights, so Westinghouse had to develop a new OV-25, as well as a new OV-15. Both of these new Silverliners (also known as TuDors, and seen as Westinghouse's answer to GE's popular PowrDoor series) now had a flat bottom, and weren't nearly as popular as the originals. However, by 1975, all Silverliners, including the single-door OV-15 and OV-25, were available as HPS units.

More new manufacturers entered the streetlighting industry. 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...

 (also known as American Electric, or ITT/American Electric) developed two new fixtures, the Model 13 and Model 25. The Model 25 was later the basis for a larger lookalike, the Model 327. All three fixtures had a boxy look that usually sported grinning diffusers, a nod to the OV-15s and M250s. (Of the three fixtures, only the Model 327 is still in production.)

The Model 327, along with GE's M1000 and Westinghouse's OV-50, sported 700–1000 watt lights (see table).

Earlier versions of the M1000 and OV-50 (and, in very rare instances, the Model 327) are noted for having fins on top of the fixture. As newer ones were made, the fins were eliminated.

Some well-known light fixtures came from the Line Material Company. In the 1960s, during the height of the mercury lights' popularity, Line Material produced the Unistyle 400 and the smaller Unistyle 175. Both of these fixtures combined various characteristics of the Silverliners and GE M-series fixtures. When the sodium era began, the company produced the boxy, more simplified Unidoor 400 (for metropolitan expressways and city boulevards) and Unidoor 175 (for smaller residential streets and alleys).

In 1982, the entire Silverliner line was discontinued, when Cooper Lighting bought out Westinghouse's streetlighting division. Today, Cooper still makes the OV-50, now called the OVL. It also continues to manufacture the OV-15 and OV-25 models for sale in Canada.

GE and Cooper continued to take streetlighting to new heights. GE was a pioneer in the full-cutoff arena, when it created a spinoff of the popular M400 in 1975. This fixture is noted for its pointed front end and lack of a diffuser. In addition, high-mast assemblies were developed for the light towers that were springing up along Interstate highways.

In 1988, ITT/American Electric also created spinoffs of its Model 13 and 25. These new fixtures, called the 113 and 125, had a more-rounded look than their respective predecessors. They have become the most popular fixtures not manufactured by GE or Westinghouse. While the Model 125 continues production today, the Model 113 was replaced by the American Electric Model 115 in 2003. In 1992, ITT sold American Electric to 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...

. In 2001, Thomas & Betts sold the street lighting division to Acuity Brands
Acuity Brands
Acuity Brands, Inc. , through its subsidiaries, engages in the design, production, and distribution of lighting equipment and specialty products worldwide. The company was founded in 2001 and is based in Atlanta, Georgia....

, where it was then spun off as American Electric Lighting.

In the mid-1980s, GE revamped its entire lineup. One, called the M400R2, had a flat bottom reminiscent of the third-generation Silverliners; the other, now called the M400A2, retained the original 1967 design but no longer had the vented door that the previous model did. Also, the M250R2 featured a slightly flatter profile than the M250R it replaced, and the M250A2 now took on the boxy profile that was previously used by the M150. In 1997, the M400 underwent a total redesign, borrowing its styling from the Thomas & Betts Model 125. In 2008, GE resumed production of the M400A2 and M400R2, which are now sold concurrently with the 1997-edition M400 and M400A models.

More recently, teardrop lamps (both existing and reproductions) have been used in favor of cobraheads, usually in both urban and suburban areas with low income demographics, but also are used in upscale developments. They are usually complemented with bishop's crook poles and more elaborate architectural elements. As opposed to GE or American Electric, King Luminaire (a division of the StressCrete Group) manufactures these.

Arc lamp

Open Arc lamps were used in the late 19th & early 20th century by many large cities for street lighting. Their bright light required that the early arc lamps be placed on rather high (60 to 150-foot) towers; as such, they might be considered the predecessor to today's high-mast lighting systems seen along major highways. They were also widely used in film and stage. Arc lamps use high current between two electrodes (typically carbon rods) and require substantial maintenance. Arc lights have mainly been used where high lumen light was needed such as lighthouses. Today very few open arc lights are still in operation, primarily in a few lighthouses and some industrial uses. The only remaining examples of original street lighting use are the moonlight tower of Austin, Texas.

A xenon lamp
Xenon arc lamp
A xenon arc lamp is a specialized type of gas discharge lamp, an electric light that produces light by passing electricity through ionized xenon gas at high pressure to produce a bright white light that closely mimics natural sunlight...

 is a high pressure sealed arc lamp, and is in common usage today where extreme brightness in a relatively small space is required, typically in motion picture projectors
Movie projector
A movie projector is an opto-mechanical device for displaying moving pictures by projecting them on a projection screen. Most of the optical and mechanical elements, except for the illumination and sound devices, are present in movie cameras.-Physiology:...

 in theaters, and stage and motion picture lighting. The sealed arc lamps do not suffer from the inefficiency and high maintenance problems of the original open arc lamps, however they are not well suited for most street lighting use.

Incandescent light

By far the most recognized type of lighting is the 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...

 using a tungsten
Tungsten
Tungsten , also known as wolfram , is a chemical element with the chemical symbol W and atomic number 74.A hard, rare metal under standard conditions when uncombined, tungsten is found naturally on Earth only in chemical compounds. It was identified as a new element in 1781, and first isolated as...

 filament. These were the first low power electric lights in cities world wide. Some can still be found in streetlight service, although many of them are using more efficient CFL light bulbs and some have been converted to MV or HPS. Others have been installed popular downtown areas of major cities to have a nostalgia effect. They were introduced some 20 years after open arc lamps, and in many cases replaced the higher maintenance arc lamps. Incandescent light also has excellent CRI rated at 100. Color temperature is generally around 2000–3200 K
Kelvin
The kelvin is a unit of measurement for temperature. It is one of the seven base units in the International System of Units and is assigned the unit symbol K. The Kelvin scale is an absolute, thermodynamic temperature scale using as its null point absolute zero, the temperature at which all...

 depending on the type of lamp. An incandescent lamp is less efficient when compared to HID
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...

 and gas discharge lighting such as Neon light.

Tungsten-halogen incandescent lights are more efficient than regular incandescent lights, and are very commonly used in theatrical and motion picture lighting due to their higher efficiency and brightness and better color temperature characteristics. They are however little used in street lighting due to their relatively short lifespan.

Standard incandescent lamps are very commonly used in traffic signals, although are increasingly being replaced by LEDs.

Fluorescent lamp

The fluorescent lamp
Fluorescent lamp
A fluorescent lamp or fluorescent tube is a gas-discharge lamp that uses electricity to excite mercury vapor. The excited mercury atoms produce short-wave ultraviolet light that then causes a phosphor to fluoresce, producing visible light. A fluorescent lamp converts electrical power into useful...

 first became common in the late 1930s. These lamps are a form of discharge lamp where a small current causes a gas in the tube to glow. The typical glow is strong in ultraviolet but weak in visible light. However, the glass envelope is coated in a mixture of phosphors that are excited by the ultraviolet light and emit visible light. Fluorescent lamps are much more efficient than incandescent lamps, and for a short time became popular in street lighting both because of the efficiency and the novelty value. Fluorescent lamps for street lighting were first introduced to the public for commercial uses at the 1939 World's Fair.

The major problems with standard fluorescent lamps for street lighting is that they are large, and produce a diffused non-directional light. They are also rather fragile. Therefore the fixtures needed to be large, and could not be mounted more than 20–30 feet above the pavement if they were to produce an acceptable light level.

Fluorescent lamps quickly fell out of favor for main street lighting, but remained very popular for parking lot and outside building illumination for roadside establishments.

Mercury vapor

In 1948, the first regular production mercury vapor (MV) streetlight assembly was developed. It was deemed a major improvement over the 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...

, and shone much brighter than incandescent or fluorescent lights. Initially people disliked them because their bluish-green light made people look like they had the blood drained from them. Other disadvantages are that a significant portion of their light output is ultraviolet, and they "depreciate"; that is, they get steadily dimmer and dimmer with age while using the same amount of energy, and in a few rare instances, they also cycle at the end of their life cycles. Mercury lamps developed in the mid 1960s were coated with a special material made of phosphors inside the bulb to help correct the lack of orange/red light from mercury vapor lamps (increasing the color rendering index(CRI)). The UV light excites the phosphor, producing a more "white" light. These are known as "color corrected" lamps. Most go by the "DX" designation on the lamp and have a white appearance to the bulb. Mercury Vapor Bulbs come in either clear or coated with powers of 50, 100, 175, 250, 400, 700 or 1,000 Watts.

As of 2008, the sale of new mercury vapor streetlights and ballasts was banned in the United States by the Energy Policy Act of 2005, although the sale of new bulbs for existing fixtures do continue. Mercury vapor fixtures can be operated with metal halide lamp
Metal halide lamp
Metal-halide lamps, a member of the high-intensity discharge family of lamps, produce high light output for their size, making them a compact, powerful, and efficient light source. By adding rare earth metal salts to the mercury vapor lamp, improved luminous efficacy and light color is obtained...

 (MH) ballasts, and are very likely to be rewired to these ballasts in the years to come. Also, in response to the ban, some older MV streetlights will most likely be modified to use either high pressure sodium or metal halide lamps in the near future, because they are known to last longer than newer luminaires. In some areas, the MV lights are being replaced with either HPS, Induction, or LED fixtures.

High pressure sodium

Around 1970, a new streetlight was put into service: The high pressure sodium
Sodium vapor lamp
A sodium vapor lamp is a gas discharge lamp that uses sodium in an excited state to produce light. There are two varieties of such lamps: low pressure and high pressure...

 (HPS) light. It was initially disliked by most residents because of its orange glow, but the sodium vapor streetlight has since become the dominant type on American roadways and most people have become accustomed to the orange/yellow glow. It is by far the most efficient light source available. Color-corrected sodium vapor lamps exist but are expensive. These "color corrected" HPS lamps have lower life and are less efficient.

There are two types of sodium vapor streetlights: high-pressure (HPS) and low-pressure (LPS). Of the two, HPS is the more-commonly used type, and it is found in many new streetlight fixtures. Sometimes, older (pre-1970) fixtures may be retrofitted to use HPS lights as well. Virtually all fixtures that are converted to HPS have previously been lit with mercury vapor. Examples of retrofitted fixtures for HPS use include the GE Form 400 and the second-generation Westinghouse OV-25 Silverliner (although later versions of this model were available from the factory as HPS units).

LPS lights are even more efficient than HPS, but produce only a single wavelength of yellow light, resulting in a CRI of zero, meaning colors cannot be differentiated. LPS lamp tubes are also significantly longer with a less intense light output than HPS tubes, so they are suited for low mounting height applications, such as under bridge decks and inside tunnels, where the limited light control is less of a liability and the glare of an intense HPS lamp could be objectionable.

HPS lamps have slightly different electrical requirements than do the older MV lamps. Both HPS and MV lamps require a transformer or ballast to change the voltage and regulate the current, however, HPS lamps also require an electrical "starter" circuit—much like older fluorescent lamps in residential use. MV lamps do not require a separate "starter" circuit because they have a special starter element within the bulb used for striking the arc. MV lamps slowly dim over time, and a twenty-year-old lamp may emit a very pleasing, but useless, soft glow, rather than the powerful blue-white light of a new MV lamp. The yellow-spectrum HPS lamps also slowly dim over time but are known for "cycling," where the lamp cycles on and off when it has reached the end of its life cycle. When cycling, the arc within the lamp extinguishes and the lamp must cool down before the starter circuit initializes a new arc. This has been the most recognized downfall of HPS.

HPS lamps by and large have the same rated lifespan as do MV lamps, and they do give increased light and efficiency. At end of life MV lamps just become dimmer and sometimes color shifting towards the green end of the spectrum and continue to consume the same amount of electricity. HPS lamps begin to suffer end-of-life cycling before the amount of useful light becomes visibly diminished. HPS lights come in wattages of 35, 50, 70, 100, 150, 200, 250, 310, 400, and 1,000 watt sizes, while LPS lights come in wattages of 18, 35, 55, 90, 135, and 180 watt sizes

Metal halide

In recent years, metal halide lamp
Metal halide lamp
Metal-halide lamps, a member of the high-intensity discharge family of lamps, produce high light output for their size, making them a compact, powerful, and efficient light source. By adding rare earth metal salts to the mercury vapor lamp, improved luminous efficacy and light color is obtained...

 (MH) streetlights have illuminated roadways and parking lots. Metal halide has long been popular in business installations and can be found in warehouses, schools, hospitals and office buildings. Unlike the old mercury lights, metal halide casts a true white light. It is not nearly as popular as its sodium counterparts, as it is newer and less efficient than sodium.

Metal halide lights have also been used for retrofitting. Virtually all fixtures that are converted to metal halide have previously been lit with high-pressure sodium (HPS). Examples of retrofitted fixtures for metal halide use include the Thomas & Betts Model 25 and Model 327, as well as full-cutoff versions of GE's M400. MH lamps suffer color shift as they age though this has been improving. Actual life expectancy is about 10,000 to 12,000 hours on average. There has also been a noted issue with the lamps "exploding/shattering" during a failure. Metal Halide light bulbs also tend to dim at the end of their life cycles, and on occasion, cycle. Sometimes, they also emit a pinkish glow at or near the end of their life cycle. High cost and low life hours has kept them from becoming popular municipal lighting sources even though they have a much improved CRI around 85. Therefore, the use of metal halide is limited mainly to city and high end street lighting. MH lights come in wattages of 70, 175, 250, 400, 1000, 1500, and 2000 watt sizes.

Ceramic discharge metal halide lamp

Ceramic discharge metal halide lamp
Ceramic discharge metal halide lamp
The ceramic discharge metal-halide lamp, mostly referred to as Ceramic Metal Halide lamp , is a relatively new source of light that is a variation of the old mercury-vapour lamp. The discharge is contained in a ceramic tube. During operation, the temperature of this ceramic tube can exceed 1200...

s will probably be the next step in streetlighting, replacing old mercury vapor and high pressure sodium lamps, especially where one wants a more clear white with better CRI (78–96) and light color retention than the blue-white mercury and orange sodium lamps. CDM lamps give five times more light than comparable tungsten incandescent light bulbs (80–117 lm/W) and will probably become more common in cities, unless LED lamps outperform them.

Induction lamp

An induction lamp features extremely long lamp life (100,000 hours), energy efficiency, high color rendering index, and a color temperature close to incandescent lights. the life of induction (also known as electrodeless fluorescent) lamps is negatively affected by heat, particularly as the temperature exceeds 35 degrees Celsius (95 degrees Fahrenheit). Since temperatures in this range commonly occur during early night hours in the summer months in much of the U.S., induction lamp applications have not extended beyond test and demonstration projects for street lighting. The larger size of the induction lamps also inhibits the effective control of the light they emit, limiting their use to lower mounting applications. There are areas in New Jersey that are using induction lighting from US Lighting Tech, Inc (Irvine, CA) to replace very old and even some pre-2008 mercury vapor lights, and have had success in their reliability and output of the fixtures. Beginning in September 2011 the City of San Diego, CA will replace some 35,000 street lights with induction lamps costing $16,000,000.00.

Compact fluorescent lamp

Compact fluorescent lamp
Compact fluorescent lamp
A compact fluorescent lamp , also called compact fluorescent light, energy-saving light, and compact fluorescent tube, is a fluorescent lamp designed to replace an incandescent lamp; some types fit into light fixtures formerly used for incandescent lamps...

s (CFL) have been used more frequently as time has improved the quality of these lamps. These lamps have been used on municipal walkways and street lighting though they are still rare at this time. Improvements in reliability still need to be made. Some issues with them are limited lumen output, high heat build up in the self contained ballast, low life/burnout due to frequent cycling (on/off) of the lamp, and the problem where most fluorescent sources become dimmer in cold weather (or fail to start at all). CFL
Compact fluorescent lamp
A compact fluorescent lamp , also called compact fluorescent light, energy-saving light, and compact fluorescent tube, is a fluorescent lamp designed to replace an incandescent lamp; some types fit into light fixtures formerly used for incandescent lamps...

 efficiency is high and CRI is excellent around 85. CFL
Compact fluorescent lamp
A compact fluorescent lamp , also called compact fluorescent light, energy-saving light, and compact fluorescent tube, is a fluorescent lamp designed to replace an incandescent lamp; some types fit into light fixtures formerly used for incandescent lamps...

 produces a color temperature around 3000 K
Kelvin
The kelvin is a unit of measurement for temperature. It is one of the seven base units in the International System of Units and is assigned the unit symbol K. The Kelvin scale is an absolute, thermodynamic temperature scale using as its null point absolute zero, the temperature at which all...

 with its light being "soft white" around that color temperature. Higher color temperatures are available.

Light emitting diodes

Light emitting diodes (LED) have virtually replaced both incandescent lamps and the occasional fluorescent lamp in traffic signal and crossing sign usage. They are rapidly developing in light output, color rendering, efficiency, and reliability. The cost of LED lighting is still extremely high compared to an incandescent lamp used for the same purpose, but the cost is decreasing rapidly. Even with the high per-unit cost, the increase in efficiency and increased lifespan make them very attractive for street lighting use; the reduced cost of electricity and maintenance in many cases can offset the increased cost of the lamp.

LEDs have yet to earn widespread usage in general street, sidewalk, or parking lot illumination as it is thought their brightness does not yet compete well with HPS, MH, or CFL lighting. However, the city of Ann Arbor, Michigan
Michigan
Michigan is a U.S. state located in the Great Lakes Region of the United States of America. The name Michigan is the French form of the Ojibwa word mishigamaa, meaning "large water" or "large lake"....

, implemented LEDs in street lighting applications March 2006 and have since expanded their use. In addition Chapel Hill
Chapel Hill, North Carolina
Chapel Hill is a town in Orange County, North Carolina, United States and the home of the University of North Carolina at Chapel Hill and UNC Health Care...

, North Carolina, entered a 12-month test program and partnership with Duke Energy
Duke Energy
Duke Energy , headquartered in Charlotte, North Carolina, is an energy company with assets in the United States, Canada and Latin America.-Overview:...

 on March 25, 2009, to evaluate the effectiveness of replacing existing HPS lighting with the more efficient LED street lighting within its vibrant downtown. In late 2008, Anchorage Alaska installed over 4,000 LED streetlights as part of a plan to convert the community's 16,000 roadway lights to efficient white light. In mid-2009, the City of Los Angeles announced a 5-year project with the Clinton Climate Initiative to replace all 140,000 of the city's existing streetlights with LED fixtures. In mid-2010, Seattle City Light
Seattle City Light
Seattle City Light is the public utility providing electrical power to Seattle, Washington and parts of its metropolitan area, including all of Shoreline and Lake Forest Park and parts of unincorporated King County, Burien, Normandy Park, Seatac, Renton, and Tukwila...

 began installing LED streetlights in a residential neighborhood as part of a plan to install 40,000 LED streetlights over the next 5 years.. Also, Atlantic City Electric in Southern NJ is also testing out LED streetlights made by 2 different manufacters in 4 communities to evaluate if LED lights are worth using over HPS. They are also asking the public's opinion on these lights. In spring of 2011, the municipally-owned energy provider for San Antonio, Texas, CPS Energy, entered into contract with GreenStar LED (of Boerne, Texas) for an order of over 25,000 LED street light fixtures.

As with other semiconductors, heat buildup in an LED dramatically reduces its life. The temperature at which this reduction in life occurs is often very near summer evening ambient temperatures. Many of the heat-removal technologies used for other semiconductor applications, such as air conditioning systems, fans, or thermal-transfer fluids, are impractical, maintenance-intensive, or cost-prohibitive for street lighting. Airborne dust from industrial and agricultural activities can impair the functioning of finned heat sinks. Achieving good maintenance-free thermal management in an often hostile environment while keeping product cost competitive is the largest hurdle to the widespread adoption of LED street lights.

Non-cutoff

The non-cutoff fixtures usually include the globe-shaped lamps that are mounted on top of lampposts. These lamps distribute their light in all directions. A major problem is created by the 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:...

 and glare, as they shoot their light upwards into trees and towards the sky rather than down towards the ground. Non-cutoff fixtures are rarely found on roadways because they tend to blind the driver.

Semicutoff

This is the most popular street lighting optic. The semicutoff fixtures usually refer to the cobraheads, but they can also apply to some lamppost-mounted fixtures that do not emit their light upwards. Most of the light can be emitted below 90 degrees, but as much as 5% of the light can also be emitted above 90 degrees. These fixtures do a very good job of spreading the light towards the ground but some uplight is possible, though not as serious as non-cutoff fixtures. Semicutoff fixtures are often mounted on tall poles. Examples of semicutoff optics include the bowl-shaped diffuser on GE's M400s made prior to 1997, and the prismatic one shared by the Westinghouse OV-25, Crouse-Hinds L250 and OVM, and Cooper OVD. These fixtures are very commonly seen with both mercury vapor and HPS lamps (and sometimes metal halide as well).

Cutoff

These optics give more light control than semicutoffs. Less than 2.5% of the light can leave the fixture above 90 degrees. Cutoff fixtures have gained popularity in recent years, as they are available from manufacturers like GE and American Electric. The cutoff lights have a wider spread of light than full-cutoffs, and they generate less glare than semicutoffs. The cutoff lenses consist of a shallow curved glass (also called a sag lens) that is visible just below the lighting area on the fixture. As with the semicutoffs, these fixtures are very commonly seen with both mercury vapor and HPS lamps (and occasionally with metal halide as well).

Full-cutoff

These lights do not allow any of the light to escape the fixture above 90 degrees. Full-cutoffs distribute their light in a defined pattern, potentially providing more light on the ground at lower power consumption. In recent years, cutoff-type lights have gained popularity. Although full-cutoff fixtures generally use HPS lamps, some metal halide and even a few mercury vapor ones are known to exist.

Small fixtures (175 watts and under)

  • Round design: This refractor is shaped like a half-circle, and is usually found on fixtures operating at 150 watts and lower. Examples of round refractors include the ones used by the American Electric Models 113/115 and General Electric M250.
  • Flat design: This refractor uses a prismatic design, and has a flat bottom. It is most commonly found on fixtures operating between 100 and 250 watts. Examples of flat refractors include the ones used by the American Electric Models 113/115, Westinghouse OV-15, Crouse-Hinds L150 and OVS and Cooper OVX and OVZ.
  • Square design: This refractor is shaped like a square, but some newer incarnations may also have a slightly-rounded bottom. Examples of square refractors include the ones used by the General Electric M250, Line-Materials Unistyle 175, McGraw-Edison Unidoor 175/250, Crouse-Hinds L150 and OVS and Cooper OVX and OVZ.
  • All three refractor designs are compatible with any small fixture, except the Westinghouse OV-10, OV-12 and OV-14B (which share the same unique refractor design).

Medium fixtures (200–400 watts)

  • Round design: This refractor is shaped like a half-circle. Usually found on General Electric M400s made prior to 1997 (and select models from 2008 onward), they are also used by the remote-ballasted GE Form 400 and Revere 400-watt models. Line-Materials/McGraw-Edison used a slightly-different round refractor design for the Unistyle 400 and Unidoor 400.
  • Prismatic designs: There are many different versions of the prismatic refractor design. A larger version of the flat design is used on the Westinghouse OV-25, Crouse-Hinds L250 and OVM and Cooper OVD. Another popular design features rounded-off corners, and is compatible with Thomas & Betts/American Electric Models 25, 125 and 325, as well as the 1997 and later editions of the General Electric M400.
  • The Unistyle 400/Unidoor 400 refractor is also interchangeable with the Model 25, and vice versa.

Large fixtures (up to 1000 watts)

  • The Westinghouse OV-50/Cooper OVL refractor is used by the remote-ballasted Westinghouse OV-35 and Revere 1000-watt models, and although there has been very little-known evidence of this, the OV-50/OVL refractor is also interchangeable with the Thomas & Betts/American Electric Model 327, and vice versa.
  • The round refractor design as seen on the General Electric M1000 can also be used with the remote-ballasted GE Form 402.

Fixture type identification

Many streetlights are marked with a NEMA wattage label
NEMA wattage label
NEMA wattage labels are used on street lighting fixtures to indicate the wattage of the lamp for maintenance purposes.Yellow sticker indicate the lamp is a sodium vapor lamp Blue sticker indicates the lamp is mercury vapor...

 to aid workers in quickly identifying them. However, the "code" isn't that hard and can be read by anyone for fun, say on a long road trip
Road trip
A road trip is any journey taken on roads, regardless of stops en route. Typically, road trips are long distances traveled by automobile.-Pre-automobile road trips:...

.

The system is as follows: The color of the sticker indicates the type of light, the number is one tenth of the power in watts. More power roughly corresponds to a brighter light.

There are three exceptions to this rule:
  • A "17" sticker adds a five to the power rating, and therefore, the light is rated at 175 watts.
  • If a sticker reads "X1," it describes a 1000-watt light.
  • If a sticker reads "3," it describes a 35-watt light.


Sticker colors:
  • Blue: Mercury vapor
  • Red: Metal halide
  • Yellow: Sodium vapor lamp
    Sodium vapor lamp
    A sodium vapor lamp is a gas discharge lamp that uses sodium in an excited state to produce light. There are two varieties of such lamps: low pressure and high pressure...


Colors vary for new LED street lights such as black for Philips Hadco RX1 and RX2 or Green for BetaLED luminaires. Also the US Lighting Tech Induction fixtures contain a green and white sticker with the Letter "I" at the end. For example a 80 watt Induction light, the sticker would read 8I.
Frequently seen power ratings:
  • "1" sticker—18 watts (LPS)-Uncommon
  • "3" sticker—35 watts (HPS/LPS)-Uncommon
  • "4i" sticker-40 watts (Induction)-New -For US Lighting Tech Induction Fixtures in NJ and CA
  • "5" sticker—50/55 watts (HPS/LPS)-Common
  • "7" sticker—70 watts (HPS/MH/LED)-Common
  • "8i" sticker-80 watts (Induction)-New -For US Lighting Tech Induction Fixtures in NJ and CA
  • "9" sticker—90 watts (LPS)-Uncommon
  • "10" sticker—100 watts (MV/HPS)-Common
  • "11" sticker—110 watts (LED)-New
  • "13" sticker—135 watts (LPS)-Uncommon
  • "15" sticker—150 watts (HPS)-Common
  • "15i" sticker-150 watts (Induction)-New -For US Lighting Tech Induction Fixtures in NJ and CA
  • "17" sticker—175 watts (MH/MV)-Common
  • "18" sticker—180 watts (LPS)-Uncommon
  • "20" sticker—200 watts (HPS)-Common
  • "25" sticker—250 watts (MV/MH/HPS)-Common
  • "25i" sticker-250 watts (Induction)-New -For US Lighting Tech Induction Fixtures in NJ and CA
  • "27" sticker—270 watts (LED)-New
  • "31" sticker—310 watts (HPS)-Uncommon
  • "37" sticker—37 watts (LED)-New - For BetaLED's luminaires in Boston, MA
  • "39" sticker—39 watts (LED)-New - For BetaLED's luminaires in Boston, MA
  • "40" sticker—400 watts (MV/MH/HPS)-Common
  • "70" sticker—700 watts (MV)-Uncommon, but common in Boston, MA
  • "70" sticker—70 watts (LED)-New
  • "X1" sticker—1000 watts (MV/HPS/MH)-Common
  • "X5" sticker-1500 watts (MH)-Uncommon
  • "X2" sticker—2000 watts (MH)-Uncommon

List of streetlight manufacturers and fixtures

Fixture name (compatible wattages) Notes

Cooper/Crouse-Hinds

L150 (50–250 watts) A small cobra head formerly the 4th generation Westinghouse OV-15.
L250 (200–400 watts) A medium cobra head formerly the 4th generation Westinghouse OV-25.
OV-15 (50–250 watts) A small cobra head, was originally the 3rd generation Westinghouse OV-15 Silverliner. It retains the same basic design of the OV-15, however is only available in Canada as a non cataloged product.
OV-25 (200–400 watts) A medium cobra head, was originally the 3rd generation Westinghouse OV-25 Silverliner. It retains the same basic design of the OV-25, however is only available in Canada as a non cataloged product.
OVL (700–1000 watts) A large cobra head, was originally the 3rd generation Westinghouse OV-50 Silverliner. It retains the same basic design of the OV-50, except it is now painted in a light grey finish (the standard color scheme for most new luminaires manufactured after 1970). Cooper still uses the OV-50 designation for its Canadian versions.
OVS (50–250 watts) A small cobra head, replaced the L150, predecessor to the OVZ.
OVM (150–400 watts) A medium cobra head, replaced the L250, predecessor to the OVD.
OVG (50–250 watts) A Small cobra head, semicutoff, smaller version of the OVD.
OVG (50–250 watts) A Small cobra head, cutoff version of OVG, smaller version of the OVY.
OVH (50–250 watts) A Small cobra head, fullcutoff version of the OVG, smaller version of the OVF. Also available with LED
LEd
LEd is a TeX/LaTeX editing software working under Microsoft Windows. It is a freeware product....

 lighting.
OVD (150–400 watts) A medium cobra head, Semicutoff fixture, replaced the OVM, this fixture uses the same glass that also appears on the Westinghouse OV-25 Silverliners, OVM and L250, it is the larger version of the OVG.
OVY (150–400 watts) A medium cobra head, the cutoff version of the OVD, it is the larger version of the OVG
OVF (150–400 watts) A medium cobra head, the fullcutoff version of the OVD, it is the larger version of the OVH
OVX (50–400 watts) A small cobra head available in semicutoff or fullcutoff, the OVX was not a direct replacement for any other model, it is slightly controversial in that it is a small cobra head that has the option for medium sized lamps often causing shorter lamp life.
OVZ (50–250 watts) A small cobra head available in semicutoff or fullcutoff, replaced the OVS.
OVC (50–250 watts) Same as the OVZ except unpainted was used in the Canadian market, however Canada now uses the OVZ.

General Electric

Form 175 (100–250 watts) Predecessor to the M250. Had the strange cone shaped refractor. (Very Rare!)
Form 109 (250–400 watts) Predecessor to the Form 400.held 600 watt incandescent lamps or 400 watt mercury vapor lamps.made from 1948 to 1955.
Form 400 (250–400 watts) Replaced the Form 109, and predecessor to the M400.also made as the form 400 powerpack an iteragate ballast version of the form 400. made from 1956 to 1959.
Form 402 (700–1000 watts) Predecessor to the M1000.
Form 7980 Claw shaped fixture. Similar to the Boston Wheeler crescent moon heads.
Form 131VR Predecessor to the Form 79RV
Form 72 Predecessor to the Form 79 luminaire
Form 45113 Pendant or span wire mount luminaire for incandescent lamps (extremely rare!)
Form 110 luminaire "Compact" luminaire. uses mercury vapor lamps or incandescent lamps. Also includes photocell.
201-SA Current NEMA luminaire first introduced in the early to mid 1980s and redesigned in 1985.
M100 (100–175 watts) A open bottom companion to the M250, also believed to be the first as a full cutoff.
M150 (50–250 watts) This PowrDoor luminaire, noted for its boxy profile, was introduced in 1980 as a companion to the M250A. In 1986, it was renamed the M250A2, and continues to use that designation today.
M250 (1959–1960)/M250R (1960–1970)M250R1 (1970–1985)/M250R2 (1985–present) (50–250 watts) Introduced in 1959, redesigned in smaller body in 1960 then redesigned in May 1970 (as the M250R1) and 1985 (as the M250R2). The original M250 from 1959 to 1960 was actually a fixture with a M-400 body but with plastic refractor. Additionally, "Crimefighter" versions exist in Chicago, with a cylinder-shaped refractor attached to the 1970 version's bodyshell.
M250A (1967–1985)/M250A2 (1986–present) (50–250 watts) This PowrDoor luminaire was introduced in 1967 as the smaller companion to the M400A, and its bodyshell was a miniature version of the M400A's. It was redesigned in 1986, taking on the M150's boxy profile, and renamed the M250A2.
M400 (1959–1970)/M400R2 (1986–1996 Reintroduced in 2008–present) /M400R3 (1997–present) (150–400 watts) Introduced in 1959, this single-door luminaire was discontinued around 1970. From 1970 to 1986, the M-400 was virtually identical to the M-400A with the exception of having a non-vented door held in place with a simple spring latch. The ballast components were mounted on the top housing. In 1986, it was revived as the M400R2, with a TuDor-esque flat profile to distinguish it from the M400A2 PowrDoor. The current version (introduced in 1997 as the M400R3) looks similar to a Thomas/Betts 125 except for a slightly bulkier housing and a bail-type latch. As of 2008, both the M400R2 and M400R3 are in concurrent production.
M400A (1967–1985)/M400A2 (1986–1996 Reintroduced in 2008–present) /M400A3 (1997–present) (150–400 watts) This PowrDoor luminaire was introduced in 1967 as the larger companion to the M250A. Earlier versions had a vented door held in place with a more complex bail latch. A full-cutoff version of this luminaire was introduced in 1975. In 1986, it was renamed the M400A2 (this incarnation did not have the vented door of the earlier models), with the arrival of the single-door M400R2. The current version (introduced in 1997 as the M400A3) looks similar to a Thomas/Betts 325 except for a slightly bulkier housing and a bail-type latch. As of 2008, both the M400A2 and M400A3 are in concurrent production.

There are rare 100 watt versions of the M400A3 that exist on the Tobin Bridge in Chelsea, Massachusetts. Additionally, "Crimefighter" versions exist in Chicago, with a bucket-shaped refractor attached to the normal 1975 full-cutoff version's bodyshell.
M1000 (700–1000 watts) Introduced in 1959, adopted fins until the mid-1960s, was redesigned in 1978, and discontinued around 1987.
GE Evolve LED (80–165 watts) GE's newest medium cobra head that utilizes LED
LEd
LEd is a TeX/LaTeX editing software working under Microsoft Windows. It is a freeware product....

 lighting, equals 70–150 watt HPS.

Hubbell

RM-series (50–250 watts) The smaller companion to the RL-series.
RL-series (200–400 watts) The larger companion to the RM-series, its look bears a resemblance to a Thomas & Betts Model 25.
RK-series (400–1000 watts) The largest of all Hubbell streetlights.

Joslyn Mfg. and Supply

MV111 (100–250 watts) Remote-ballasted fixture, the smaller companion to the MV131. The "MV" designation is said to stand for "Mercury Vapor," and the majority of all Joslyn luminaires still use mercury lights.
MV131 (250–400 watts) Remote-ballasted fixture, the larger companion to the MV111.
MV121 (100–250 watts) The smaller companion to the MV141. It looks like a spaceship with a refractor stuck underneath.
MV141 (250–400 watts) The larger companion to the MV121.
MV151 (400–1000 watts) The largest companion of all the Joslyn streetlamps.

Line Material Industries/McGraw-Edison

Ovalite (100–400 watts) Remote-ballasted fixture, in the tradition of the Westinghouse OV-10/20/35 and GE Form series. The earliest Ovalite had similar style as a GE Form 109 but later it was changed and was still called an Ovalite.
Unistyle 175/250 (100–250 watts) The smallest member of the Unistyle family.
Unistyle 400 (250–400 watts) Most people think of the 400 as the largest member of the Unistyle family, but it's the mid-sized fixture.
Unistyle 1000 (700–1000 watts) This very rare fixture was the largest member of the Unistyle family.
Unidoor 175/250 (100–250 watts) Replaced the Unistyle 175/250.
Unidoor 400 (200–400 watts) Replaced the Unistyle 400
Spherolite (50-295 watts) Pendant type luminaire. Uses incandescent or mercury vapor lamps.
Suburbanaire (50-295 watts) "NEMA HEAD" style yard light for incandescent or mercury vapor lamps. Dates back to 1963
Dusk-To-Dawner (100, 175, & 250 watts) Dusk to dawn cobrahead security light for mercury vapor lamps.

ITT/Thomas & Betts/American Electric Lighting(AEL)

Model 13-000 (50–250 watts) Same as the boxier, bulkier looking Model 13 that would follow, but had a similar shape of a Model 113 and had more of a Silverliner appearance.
Model 25-000 (250–400 watts) Same as the boxier, bulkier looking Model 25 that would follow, but more of a Silverliner appearance.
Model 327-000 (700–1000 watts) Same as the boxier, bulkier looking Model 327 that would follow, but more of a Silverliner appearance.
Model 13 (50–250 watts) The smaller companion to the Model 25. A power pad version of this fixture was also available, and it was the immediate predecessor to the Model 313.
Model 25 (200–400 watts) The larger companion to the Model 13, and later inspired an even larger version.
Model 327 (700–1000 watts) A spinoff of the Model 25, and as of this writing it is still in production as AEl's only 1 KW fixture.
Model 113 (50–250 watts) Replaced the Model 13. Has softer, more rounded lines than its predecessor. Its bodyshell resembles a more modernized version of the original Model 13.
Model 313 (50–250 watts) The power pad version of the 113.
Model 115 (50–400 watts) Replaced the Model 113. Introduced in 2003 by Acuity Brands Lighting /American Electric.
Model 315 (50–400 watts) The power pad version of the 115.
Model 125 (150–400 watts) Replaced the Model 25. Has softer, more rounded lines than its predecessor. GE's M400 has used this design since 1997, but with some noticeable differences: The 125 has a slightly smaller housing than the M400 and an internal latch, as evidenced by its indented front end.
Model 325 (150–400 watts) The power pad version of the 125.
Model 413 (50–150 watts) The 413 was created for International customers so they could fit more fixtures per container. The 115 was redesigned so 40 cartons fit on a pallet, thus eliminating the need for the 413.
Roadway-Area-SRX (35–90 watts) AEl's smaller LPS fixture.
Roadway-Area-SP2 (90–180 watts) AEL's larger LPS fixture.
Durastar 2000 (50–250 watts) Semicutoff or fullcutoff fixture, manufacture of fiberglass and uses unique Duralock docking station, the fixture is composed of two parts the docking station that contains the slipfitter, and the fixture its self, the fixture locks on to the mounting station.
Durastar 3000 (150–400 watts) Semicutoff or fullcutoff fixture, manufacture of fiberglass and uses unique Duralock docking station, the fixture is composed of two parts the docking station that contains the slipfitter, and the fixture its self, the fixture locks on to the mounting station.
Corvus CVM (70–250 watts) Available in either Cutoff or Full Cutoff the Corvus CVM is a small sized cobra head the is slightly more decorative then most others.
Corvus CVL (100–400 watts) Available in either Cutoff or Full Cutoff the Corvus CVl is a medium sized cobra head the is slightly more decorative then most others.
LEDR (70–100 watts) The LEDR is AELs only LED
LEd
LEd is a TeX/LaTeX editing software working under Microsoft Windows. It is a freeware product....

 street lighting fixture, it is available in 70 or 100 watts and is equal to a 50–100 watt HPS
Sodium vapor lamp
A sodium vapor lamp is a gas discharge lamp that uses sodium in an excited state to produce light. There are two varieties of such lamps: low pressure and high pressure...

 cobra head.

Lithonia Lighting

TDS2 Lithonia's model # for the Durastar 2000.
TDS3 Lithonia's model # for the Durastar 3000.
CHE Same as the American Electric Lighting Roadway 413 luminaire.
CHL Same as the AEL Roadway 115.
CHLD Same as the AEL Roadway 315.
CHM Same as the AEL Roadway 125.
CHMD Same as the AEL Roadway 325.
CHX Same as the AEL Roadway 327.
TMM Same as the AEL Multi-Mount 285.
TDR Same as the AEL Interstate II series 775.
TSL Same as the AEL Signlite 875.

Revere

Revere 400 (250–400 watts) Resembles a Westinghouse OV-25 Silverliner, but uses an M400-style refractor.
Revere 1000 (700–1000 watts) Resembles a Westinghouse OV-50 Silverliner, but with a shorter neck.

Westinghouse

AK-10 Incandescent gumball or deep bowl teardrop luminaire
OV-10 (100–250 watts) Predecessor to the OV-12.
OV-20 (250–400 watts) Predecessor to the OV-25.
HMA-60 (700–1000 watts) Companion model to the OV-20
OV-35 (700–1000 watts) Predecessor to the OV-50.
MO-8 (100–175 watts) A flat-bottomed Silverliner in a cobrahead style with internal reflector, believed to be the Westinghouse full-cutoff fixture. Ballast and slipfitter is accessed by simply unscrewing a stainless screw on the top and the top "folds open" revealing a ballast and slipfitter found on the bottom casing.
MO-9 (100–175 watts) A flat bottomed Silverliner with an external stamped reflector and a ballast casing attached.
OV-12 (100–250 watts) Replaced the OV-10, predecessor to the OV-15. Introduced in 1960. This fixture looks like a shrunken-down OV-50.
OV-14B (100–250 watts) Replaced the OV-10, predecessor to the OV-15. Introduced in 1957. It looks like a smaller version of the 1957 design of OV-25. Also those were mostly used in Canada when the United States had the OV-12 but the OV-14B can be found in the USA but is quite rare.
OV-15 (50–250 watts) Replaced the OV-12 and OV-14B as the smallest Silverliner. Introduced in 1965 and redesigned in 1979. The Crouse-Hinds L150 was originally designated as an OV-15. This fixture continues Canadian production as the Cooper OV-15.
OV-15 TuDor (50–250 watts) Introduced in 1970, this split-door luminaire featured a flatter profile and was designed to compete directly with the 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...

 M250A Powr/Door luminaire.
OV-25 (250–400 watts) Mid-sized Silverliner, and the most popular streetlight fixture of all-time. Introduced in 1957, redesigned in 1964 and again in 1979. This is believed to be the first-ever integral-ballasted fixture. A remote-ballasted version was also available, with a truncated back as its most notable feature. The Crouse-Hinds L250 was originally designated as an OV-25. This fixture continues Canadian production as the Cooper OV-25.
OV-25 TuDor (250–400 watts) Introduced in 1970, this split-door luminaire featured a flatter profile and was designed to compete directly with the 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...

M400A Powr/Door luminaire.
OV-50 (700–1000 watts) The largest Silverliner, introduced in 1963. Adopted fins in the mid-1960s. This fixture continues U.S. production as the Cooper OVL, and it also continues Canadian production as the Cooper OV-50.

Philips Hadco

|-
|RX1 (70–110 watts)
|A small LED street light found in Boston, Massachusetts.
|-
|RX2 (270 watts)
|A medium LED street light found in Boston, Massachusetts.
!colspan=2|
|-
|}

BetaLED

|-
|Type 3 STR-LWY-1S-HT (37, 39 or 70 watts)
|A small or medium LED street light found in Boston, Massachusetts.
|-
|}
Note 1: Unistyle luminaires are known for their arched top and sloped front end, while their Unidoor successors have a boxy profile. The 175 designation is used for the smaller versions of both styles by most people, but some use the 250 designation, since they were capable of light sizes of up to 250 watts.

Note 2: Silverliner luminaires that have been rebuilt and painted light grey are referred to as "Greyliners"/"Grayliners." Usually, they include the single-door OV-15 and OV-25 Silverliners, and the OV-50 was also switched to a Greyliner scheme when Cooper Lighting bought out Westinghouse's streetlighting division in 1982. Its immediate successor, the Cooper OVL, is also considered to be a Greyliner. Although other Cooper/Crouse-Hinds luminaires, like the OVM/OVS and OVX/OVZ, use the grey color scheme, they are not referred to as Greyliners.

Note 3: It is also very common to reuse older luminaires with newer parts. The most common practice is retrofitting a normal MV luminaire to use HPS lamps. This is being done in most small towns and a few mid-sized cities because it is cheaper to rewire an existing fixture rather than buying completely new ones. Sometimes, normally-silver luminaires, like the 1959-era GE M250s/M400s and Line-Material Unistyles/Unidoors, are repainted light grey; the most common examples of these are the aforementioned Westinghouse Greyliners.

Note 4: GE's revival of the M400A2 and M400R2 designs in 2008 is believed to be the first time ever that a manufacturer has resumed production of a previous design. Despite this, the newer 1997 "American Electric" designs also continue to be in production.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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