Editing Light pollution (section)

===Re-designing lighting plans===

In some cases, evaluation of existing plans has determined that more efficient lighting plans are possible. For instance, light pollution can be reduced by turning off unneeded outdoor lights, and lighting stadiums only when there are people inside. Timers are especially valuable for this purpose. One of the world's first coordinated ''legislative'' efforts to reduce the adverse effect of this pollution on the environment began in [[Flagstaff, Arizona]], in the U.S. There, more than three decades of ordinance development has taken place, with the full support of the population,<ref>[http://www.flagstaffdarkskies.org Flagstaff Dark Skies Coalition] {{Webarchive|url=https://web.archive.org/web/20110118055950/http://www.flagstaffdarkskies.org/ |date=2011-01-18 }}. Flagstaffdarkskies.org (2011-10-24). Retrieved 2011-12-03.</ref> often with government support,<ref>[http://www.coconino.az.gov/comdev.aspx?id=144&terms=lighting Coconino County Lighting and General Codes] {{webarchive|url=https://web.archive.org/web/20110721032922/http://www.coconino.az.gov/comdev.aspx?id=144&terms=lighting |date=2011-07-21 }}. Coconino.az.gov (2008-01-07). Retrieved 2011-12-03.</ref> with community advocates,<ref>[http://docs.darksky.org/AGM/2009/Luginbuhl.ppt Arizona IDA presentation on Lighting issues (PowerPoint)] {{webarchive|url=https://web.archive.org/web/20100706041538/http://docs.darksky.org/AGM/2009/Luginbuhl.ppt |date=2010-07-06 }}. darksky.org.</ref> and with the help of major local observatories,<ref>[http://www.lowell.edu/ Lowell Observatory] {{Webarchive|url=https://web.archive.org/web/20110302233420/http://www.lowell.edu/ |date=2011-03-02 }}. Lowell.edu. Retrieved 2011-12-03.</ref> including the [[United States Naval Observatory Flagstaff Station]]. Each component helps to educate, protect and enforce the imperatives to intelligently reduce detrimental light pollution.

One example of a lighting plan assessment can be seen in a report originally commissioned by the Office of the Deputy Prime Minister in the United Kingdom, and now available through the [[Department for Communities and Local Government]].<ref>{{cite web|title=Towards good practice|work=Lighting in the countryside|url=http://www.communities.gov.uk/publications/planningandbuilding/lighting|access-date = 2008-01-16| archive-url = https://web.archive.org/web/20080108232309/http://www.communities.gov.uk/publications/planningandbuilding/lighting| archive-date = January 8, 2008}} [[Department for Communities and Local Government]], United Kingdom.</ref> The report details a plan to be implemented throughout the UK, for designing lighting schemes in the countryside, with a particular focus on preserving the environment.

In another example, the city of [[Calgary]] has recently replaced most residential street lights with models that are comparably energy efficient.<ref>[http://www.calgary.ca/Transportation/Roads/Pages/Traffic/Traffic-signals-and-streetlights/Envirosmart-streetlight-retrofit/EnviroSmart-streetlight-retrofit.aspx The City of Calgary: Envirosmart Streetlight Retrofit Program] {{webarchive|url=https://web.archive.org/web/20120502014929/http://www.calgary.ca/Transportation/Roads/Pages/Traffic/Traffic-signals-and-streetlights/Envirosmart-streetlight-retrofit/EnviroSmart-streetlight-retrofit.aspx |date=2012-05-02 }}. calgary.ca</ref> The motivation is primarily operation cost and environmental conservation. The costs of installation are expected to be regained through energy savings within six to seven years.

The Swiss Agency for Energy Efficiency (SAFE) uses a concept that promises to be of great use in the diagnosis and design of road lighting, "''consommation électrique spécifique'' (''CES'')", which can be translated into English as "specific electric power consumption (SEC)".<ref>{{cite web |url=http://www.efficace.ch/f/IndexAktuell.html |title=S.A.F.E > Actualité |publisher=Efficace.ch |access-date=2010-09-04 |archive-date=2011-05-12 |archive-url=https://web.archive.org/web/20110512162225/http://www.efficace.ch/f/IndexAktuell.html |url-status=live }}</ref> Thus, based on observed lighting levels in a wide range of Swiss towns, SAFE has defined target values for electric power consumption per metre for roads of various categories. Thus, SAFE currently recommends an SEC of two to three watts per meter for roads less than ten metres wide (four to six for wider roads). Such a measure provides an easily applicable environmental protection constraint on conventional "norms", which usually are based on the recommendations of lighting manufacturing interests, who may not take into account environmental criteria. In view of ongoing progress in lighting technology, target SEC values will need to be periodically revised downwards.
[[File:110213 LED vs Sodium vs Mercury.jpg|thumb|Crossroad in Alessandria, Italy: [[luminaire]]s with [[Mercury Lamp|mercury lamps]] are in the background, [[LED street light]]s in the middle, [[luminaire]]s with [[high pressure sodium lamp]]s are in the foreground.]]

A newer method for predicting and measuring various aspects of light pollution was described in the journal [[Lighting Research & Technology]] (September 2008). Scientists at [[Rensselaer Polytechnic Institute]]'s Lighting Research Center have developed a comprehensive method called Outdoor Site-Lighting Performance (OSP), which allows users to quantify, and thus optimize, the performance of existing and planned lighting designs and applications to minimize excessive or obtrusive light leaving the boundaries of a property. OSP can be used by lighting engineers immediately, particularly for the investigation of glow and trespass (glare analyses are more complex to perform and current commercial software does not readily allow them), and can help users compare several lighting design alternatives for the same site.<ref>[http://newswise.com/articles/view/544092/ Lighting Research Center Develops Framework for Assessing Light Pollution] {{Webarchive|url=https://web.archive.org/web/20110512173038/http://newswise.com/articles/view/544092/ |date=2011-05-12 }} Newswise. Retrieved 2008-09-08.</ref>

In the effort to reduce light pollution, researchers have developed a "Unified System of Photometry", which is a way to measure how much or what kind of [[street light]]ing is needed. The Unified System of Photometry allows light fixtures to be designed to reduce energy use while maintaining or improving perceptions of visibility, safety, and security.<ref>{{cite journal |doi=10.1191/1365782804li114oa |author=Rea, M. |author2=J.D. Bullough |author3=J.P. Freyssinier |author4=A. Bierman |name-list-style=amp |date=2004 |title=A proposed Unified System of Photometry |journal=Lighting Research and Technology |volume=36 |issue=2 |pages=85–111 |s2cid=14721508 }}{{Dead link|date=July 2018 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> There was a need to create a new system of light measurement at night because the biological way in which the eye's rods and cones process light is different in nighttime conditions versus daytime conditions. Using this new system of photometry, results from recent studies have indicated that replacing traditional, yellowish, [[High pressure sodium|high-pressure sodium]] (HPS) lights with "cool" white light sources, such as induction, [[Fluorescent lamp|fluorescent]], [[Ceramic discharge metal halide lamp|ceramic metal halide]], or [[LED]]s can actually reduce the amount of electric power used for lighting while maintaining or improving visibility in nighttime conditions.<ref>{{cite journal|last1=Rea|first1=M.|last2=Yuan|first2=Z.|last3=Bierman|first3=A.|title=The unified system of photometry applied to remote airfield lighting|journal=Lighting Research and Technology|volume=41|pages=51–70|date=2009|doi=10.1177/1477153508095735|s2cid=111174811}}</ref>

The [[International Commission on Illumination]], also known as the CIE from its French title, la Commission Internationale de l'Eclairage, will soon be releasing its own form of unified photometry for outdoor lighting.