Lighting Regulations and Policies

Outdoor lighting regulations are a great tool for ensuring that councils implement good, safe outdoor lighting. Well-written regulations, with proper lighting installed, will save the public money and increase safety.

  • How can you identify if your community has lighting regulations?
  • How to ensure lighting regulations are enforced
  • How to advocate for a lighting regulations

How to Identify if Your Community Has Lighting Regulations

Contact your local council and ask, or check your city’s website to see if you can search its laws and regulations. If you can’t find the relevant information on the website, try a web search using your town or city’s name along with the words “lighting regulations.”

Key phrases that you are looking for in these regulations are; “outdoor lighting,” “exterior lighting,” “light pollution” or “light trespass.”

Your search may turn up policies that regulate specific types of lighting; a common example of this is language in an ordinance regulating outdoor signs that incidentally mentions lighting. Look for search results that suggest a general and freestanding policy, which tends to be comprehensive in nature. Often these sections will be headed with simple descriptive titles like “Outdoor Lighting”. If you don’t find this, it’s a good bet that your community doesn’t have an outdoor lighting policy.

How to Ensure Lighting Regulations are Enforced

Many towns and DarkSky advocates think that the adoption of lighting codes/laws/policies is the end of their efforts. Instead, it’s often the beginning and ongoing education is key. Otherwise, a community might forget why it even adopted the original code and how it helps its citizens. The details of code enforcement may or may not be spelt out in the outdoor lighting regulation itself, so check the code to be sure. Many regulations are complaint-driven, but there are things to look out for before making a complaint about someone’s lighting:

  1. First, DarkSky recommends always having friendly neighbourly discussions with lighting offenders before making a complaint to the local government.
  2. Second, some codes have a grandfathering provision exempting lighting that was in place before the ordinance was passed. If your city has such a provision, many older lights may be exempt (e.g. listed buildings). There may be other exceptions or conditions in the code too, so be sure to look for those before making a complaint.

If a complaint is valid, then city officials might need to make a nighttime site visit to verify the claim. Often they’ll be reluctant to – that’s understandable as most of us don’t want to work beyond our normal work schedule. Stick to the facts (rather than making an emotional appeal), but be persistent when discussing your concerns with city officials. Remember that while your city works for you, it’s likely that the code enforcement office has too much to do and not enough resources to get everything done at once.

How to Advocate for an Outdoor Lighting Ordinance

Getting new laws passed is a lengthy process. A good way to start is to make an appointment with a member of city staff, the mayor or your councillor or MP. Don’t worry if your first meeting ends up being a short one. It’s entirely possible that your local officials don’t know what a lighting policy is or why one would be needed. It’s also very important to be prepared with relevant and objective information (you might want to check out our Lighting for Policy Makers webpage). Keep the discussion focused on the positive outcomes for the city and try to anticipate any questions that the officials might ask about costs and safety issues.

DarkSky UK has many resources that can assist you, which you can find in our “members” section.

In developing a new policy, there will be many factors to consider. Beyond the basic shielding requirements, DarkSky UK recommends that an ordinance address light trespass, lighting curfews and spectrum (see our LED guidelines)

There are a host of other questions that need answering, including

  • Should lighting zones be adopted?
  • Are any special considerations needed to protect environmentally sensitive areas or an astronomical observatory?
  • Should the new rules be applied to older, non-conforming lighting?
  • Should there be a timeline for when all lighting must be brought into compliance?

Outdoor Lighting Basics

IDA-UK recognizes that we need good outdoor lighting at night, but any required lighting be used thoughtfully. To minimize the harmful effects of light pollution, lighting should

  • Only be on when needed
  • Only light the area that needs it
  • Be no brighter than necessary
  • Minimize blue light emissions
  • Eliminate upward-directed light

Glossary of Lighting Terms

Types of Light (The Science Bit…)

Most people are familiar with incandescent or compact fluorescent bulbs for indoor lighting, but outdoor lighting usually makes use of different, more industrial sources of light. Common light sources include low-pressure sodium (“LPS”), high-pressure sodium (“HPS”), metal halide, and, most recently, light-emitting diodes (“LEDs”).

LPS is an old technology that is no longer being manufactured. It was favoured for use around observatories and some environmentally sensitive areas. Narrow-band amber LEDs emulate the colour.

HPS is commonly used for street lighting in many cities. Although it still emits an orange-coloured light, its colouring is more “true to life” than that of LPS.

In areas where it’s necessary to use white light, two common choices are metal halide and LEDs. One of the advantages of LED lighting is that it can be dimmed. Thus, instead of always lighting an empty street or parking lot at full brightness, LEDs can be turned down or off when they aren’t needed and then brought back to full brightness as necessary. This feature both saves energy and reduces light pollution during the night.

Because of their reported long life and energy efficiency, LEDs are rapidly coming into widespread use, replacing the existing lighting in many cities. However, there are important issues to consider when making such a conversion. See our LED Practical Guide for more information.

Colour Matters

It is crucial to control upward-directed light, but we know that the colour of light is also very important. Some lights have large amounts of blue light in their spectrum. Because blue light brightens the night sky more than any other colour of light, it’s important to minimize the amount emitted. Exposure to blue light at night has also been shown to harm human health and endanger wildlife. IDA recommends using lighting that has a colour temperature of no more than 2,700 Kelvins.

Lighting with lower colour temperatures has less blue in its spectrum and is referred to as being “warm.” Higher colour temperature sources of light are rich in blue light. IDA recommends that only warm light sources be used for outdoor lighting.

several diagrams showing the light spectra of various types of artificial and natural light.
Sunlight vs L.E.D. vs Florescent Light Spectra Comparison

Wildlife & Ecosystems

For billions of years, all life has relied on Earth’s predictable rhythm of day and night. It’s encoded in the DNA of all plants and animals. Humans have radically disrupted this cycle by lighting up the night.

When we add light to the environment, that has the potential to disrupt habitat, just like running a bulldozer over the landscape can.”

— Chad Moore, formerly of the National Park Service

Plants and animals depend on Earth’s daily cycle of light and dark rhythm to govern life-sustaining behaviours such as reproduction, nourishment, sleep and protection from predators.

Scientific evidence suggests that artificial light at night has negative and deadly effects on many creatures including amphibians, birds, mammals, insects and plants.

Artificial Lights Disrupt the World’s Ecosystems

Nocturnal animals sleep during the day and are active at night. Light pollution radically alters their nighttime environment by turning night into day.

According to research scientist Christopher Kyba, for nocturnal animals,

“the introduction of artificial light probably represents the most drastic change human beings have made to their environment.”

“Predators use light to hunt, and prey species use darkness as cover,” Kyba explains “Near cities, cloudy skies are now hundreds, or even thousands of times brighter than they were 200 years ago. We are only beginning to learn what a drastic effect this has had on nocturnal ecology.”

Chris Kyba

Glare from artificial lights can also impact wetland habitats that are home to amphibians such as frogs and toads, whose nighttime croaking is part of the breeding ritual. Artificial lights disrupt this nocturnal activity, interfering with reproduction and reducing populations.

Artificial Lights Can Lead Baby Sea turtles to their Demise

Sea turtles live in the ocean but hatch at night on the beach. Hatchlings find the sea by detecting the bright horizon over the ocean. Artificial lights draw them away from the ocean. In Florida alone, millions of hatchlings die this way every year.

Artificial Lights have Devastating Effects on Many Bird Species

Photo by Michael Menefee

Birds that migrate or hunt at night navigate by moonlight and starlight. Artificial light can cause them to wander off course and toward the dangerous nighttime landscapes of cities. Every year millions of birds die colliding with needlessly illuminated buildings and towers. Migratory birds depend on cues from properly timed seasonal schedules. Artificial lights can cause them to migrate too early or too late and miss ideal climate conditions for nesting, foraging and other behaviours.

Ecosystems: Everything is Connected

a 15 second exposure showing the behaviour of insects around artificial lights. Image: Nevit Dilman It is dark and there is a streetlight attracting insects to it. Because it is a long exposure you can see the trails the insects make as they travel towards and around the light.
a 15 second exposure showing the behaviour of insects around artificial lights. Image: Nevit Dilman

Many insects are drawn to light, but artificial lights can create a fatal attraction. Declining insect populations negatively impact all species that rely on insects for food or pollination. Some predators exploit this attraction to their advantage, affecting food webs in unanticipated ways.

Measuring Light Pollution

Jesus Acosta, the impact of light pollution as seen during a power outage.

Due to light pollution, the night sky over many of our cities is hundreds of times brighter than a natural, starlit sky. This skyglow hides the stars from our sight and prevents us and all life on Earth from experiencing a natural night, even in areas hundreds of miles away from towns and cities.

How can you help?

Lincoln cathedral at night
Lincoln Cathedral. Image: Mark McNeill

Become a Citizen Scientist

The CPRE does an annual star count which you can do from your back garden or yard. Anyone can take part in it, and you don’t need specialist training or equipment. Find out more here.

Participating in the Globe at Night citizen-science campaign is a great way to help our understanding of skyglow and its impact. No special tools are required and observations can easily be reported by smartphone, tablet or computer.

It’s also possible to use your smartphone to make night sky brightness measurements. The Dark Sky Meter app makes use of the iPhone camera to record the brightness of the night sky, while the Loss of the Night app walks the user through the sky as measurements are made with a different sensitive tool – the human eye. It’s available for both Android devices and iPhones. And now, thanks to the MySkyatNight project, you can also do your own analysis of all this available data.

Jodrell Bank under a starry sky but with some light pollution showing in the background
Jodrell Bank under a starry but light polluted sky. Image: Mark McNeill

Another way you can help is by participating in the Cities at Night project, which relies on citizen scientists to map and identify photos of cities taken from the International Space Station. This valuable information helps researchers better assess light pollution across of the globe.

In addition to the smartphone apps and the Globe at Night project, more rigorous, long-term monitoring is also being conducted. The section below describes standards for collecting and reporting skyglow measurements.

How Can You Help With Skyglow Observations?

The introduction of the Sky Quality Meter and the International Year of Astronomy Lightmeter have led to a large number of permanent online skyglow monitoring stations. At the same time, a number of individuals and groups have developed their own non-commercial devices for measuring skyglow.

If there is a dark sky park or reserve near you, they are always on the lookout for volunteers to help them with their dark sky measurements.

a before and after picture showing how bad lighting can be improved using IDA guidelines
a before and after picture showing how bad lighting can be improved using DarkSky guidelines. Image: DarkSky

Human Health

Exposure to Light Pollution Harms Your Health

Research suggests that light pollution negatively effects human health, increasing risks for obesity, depression, sleep disorders, diabetes, breast cancer and more.

Many species (including humans) need darkness to survive and thrive.

— American Medical Association Council on Science and Public Health (2012)

Circadian Rhythm and Melatonin

Like most life on Earth, humans have a biological clock called your circadian rhythm. It is a sleep-wake pattern governed by the day-night cycle. Artificial light at night disrupts that cycle.

Our bodies produce the hormone melatonin in response to our circadian rhythm. Melatonin helps keep us healthy. It induces sleep, boosts the immune system, lowers cholesterol, and helps the functioning of the thyroid, pancreas, ovaries, testes and adrenal glands. Nighttime exposure to light pollution suppresses melatonin production.

Blue Light is the Most Harmful Type of Light Pollution

Exposure to blue light at night is harmful. Unfortunately, most LEDs used for outdoor lighting — as well as computer screens, TVs, and other electronic displays — have a white colour which is dominated by blues.

According to experts at Harvard Medical School,

“If blue light does have adverse health effects, then environmental concerns, and the quest for energy-efficient lighting, could be at odds with personal health. ”

A 2016 American Medical Association report expressed concern about exposure to blue light from outdoor lighting and recommends shielding all light fixtures and only using lighting with 3000K colour temperature and below.

To minimize harm from blue light in your home, choose the right light bulb and download a colour temperature app that adapts your electronic screen to the time of day – cool light during the day and warm light at night.

Colour Temperature Apps:

  • F.lux is available for Mac OS/X, Windows, Linx and (jailbroken) iPhones and iPads.
  • For those with Apple devices using the iOS 9.3 operating system and above, the Night Shift app is pre-installed. Click here to learn how to use it. 
  • Lux is available for Android devices free or for pay.
  • Twilight is available for smartphones or tablets.

Choosing the Right Bulb


In this picture both lights are “white” but the bulb on the left is rich in blue light, while the one on the right isn’t. The warmer light on the right is the better, healthier one to choose.

All packaging for new light bulbs provides colour temperature information. Use low-colour temperature light sources for interior and exterior light. Their light is less harsh and less harmful to human health and the environment. Look for warm white sources with a colour temperature of 3000K or lower.

Kelvin Temperature Scale

Higher colour temperatures mean white light that is more blue-ish and less warm, the kind that should be avoided after dusk.

3 types of light bulbs showing different effects of colour temperatures.
Image: Wikipedia, shows three different white lights with blue, yellow and orange tints to them. The orange 2700K light is the healthiest and most environmentally positive type to chose.

Glare from Bad Lighting is a Safety Hazard

Glare from poorly shielded outdoor lighting is also harmful to your health because it decreases vision by reducing contrast. This limits our ability to see potential dangers at night. Ageing eyes are especially affected.

“Glare from nighttime lighting can create hazards ranging from discomfort to frank disability.”

American Medical Association Council on Science and Public Health (2012)

Night Sky Heritage

The nighttime environment is a precious natural resource for all life on Earth, but the glow of uncontrolled outdoor lighting has hidden the stars and changed our perception of the night.

“For my part I know nothing with any certainty, but the sight of the stars makes me dream.”

— Vincent van Gogh

The Natural Night Sky Inspires

Until recently, for all of human history, our ancestors experienced a sky brimming with stars – a night sky that inspired science, religion, philosophy, art and literature, including some of Shakespeare’s most famous sonnets.

The natural night sky is our common and universal heritage, yet it’s rapidly becoming unknown to the newest generations.

Van Gogh painted his famous “Starry Night” in Saint Rémy, France, in 1889. Now, the Milky Way can no longer be seen from there. If he were alive today, would he still be inspired to paint “Starry Night”?

Experiencing the night sky provides perspective, and inspiration, and leads us to reflect on our humanity and place in the universe. The history of scientific discovery and even human curiosity itself is indebted to the natural night sky.

Without the natural night sky we could not have:

  • Navigated the globe
  • Walked on the Moon
  • Learned of our expanding universe
  • Discovered that humans are made of stardust
Some examples of dark sky objects you can see and image in a dark sky site.
Deep sky objects that are visible at a proper dark sky site. Image: A montage by Chris Duffy & Dr Martin Kitching

International Dark-Sky Places Program

For these reasons, IDA established the International Dark Sky Places Program in 2001 to recognise excellent stewardship of the night sky. Designations are based on stringent outdoor lighting standards and innovative community outreach.

Since the program began, more than one hundred Parks, Communities, Reserves, and Sanctuaries have received International Dark Sky Place designations.

Lighting, Crime & Safety

There is no clear scientific evidence that increased outdoor lighting deters crime and in some cases increased outdoor lighting actually increases crime.

A 2015 study published in the Journal of Epidemiology and Community Health found that streetlights don’t prevent accidents or crime, but do cost a lot of money. The researchers looked at data on road traffic collisions and crime in 62 local authorities in England and Wales and found that lighting had no effect, whether authorities had turned them off completely, dimmed them, turned them off at certain hours, or substituted low-power LED lamps.

According to the 2015 study, “[W]hen risks are carefully considered, local authorities can safely reduce street lighting saving both costs and energy … without necessarily impacting negatively upon road traffic collisions and crime.” In fact, most property crime occurs in the light of the day. And some crimes like vandalism and graffiti actually thrive on night lighting.

A 2011 study of London street lighting and crime, showed that there is no good evidence that increased lighting reduces total crime.” A 1997 National Institute of Justice study concluded, “We can have very little confidence that improved lighting prevents crime.”

The truth is bright, glaring outdoor lighting can increase crime and decrease safety by making victims and property easier to see. A Chicago Alley Lighting Project showed a correlation between brightly lit alleyways and increased crime.

Streetlight Glare

Photo by Jim Richardson.

Brighter Does Not Mean Safer:

According to a 2012 AMA report, “Glare from nighttime lighting can create hazards ranging from discomfort to frank visual disability.”

Outdoor lighting is intended to enhance safety and security at night, but too much lighting can actually have the opposite effect. Visibility should always be the goal. Glare from bright, unshielded lights actually decreases safety because it shines into our eyes and constricts our pupils. This can not only be blinding, it also makes it more difficult for our eyes to adjust to low-light conditions.

The Solution? The Right Type of Light Used in the Right Way at The Right Time

Lighting that is the correct type, correct brightness, pointed and switched on only where you need it, is the solution. Why not become a member of the IDA-UK to find out more?

Energy Waste

Lighting that emits too much light or shines when and where it’s not needed is wasteful. Wasting energy has huge economic and environmental consequences.

In an average year in the U.S. alone, outdoor lighting uses about 120 terawatt-hours of energy, mostly to illuminate streets and parking lots. That’s enough energy to meet New York City’s total electricity needs for two years! We estimate that at least 30 percent of all outdoor lighting in the U.S. alone is wasted, mostly by lights that aren’t shielded. That adds up to £3 billion and the release of 21 million tons of carbon dioxide per year! To offset all that carbon dioxide, we’d have to plant 875 million trees annually.

Environmental responsibility requires energy efficiency and conservation

  • Installing quality outdoor lighting could cut energy use by 60–70 percent, save billions of £££ and cut carbon emissions.
  • Outdoor lighting should be fully shielded and direct light down where it is needed, not shining up into the sky.
  • Unnecessary indoor lighting – particularly in empty office buildings at night – should be turned off.

New lighting technologies can help conserve energy

  • LEDs and compact fluorescents (CFLs) can help reduce energy use and protect the environment, but only warm-white bulbs should be used. Learn more about LEDs and colour temperature from our LED Practical Guide.
  • Dimmers, motion sensors and timers can help to reduce average illumination levels and save even more energy.

Quality lighting design reduces energy use and therefore energy dependence. It also reduces carbon emissions, saves money and allows us to enjoy the night sky. Watch a clip of the documentary The City Dark to learn how lighting design can reduce light pollution and also conserve energy.