Lighting Clearinghouse

Thanks to new technologies and higher quality standards, outdoor lighting is significantly more economical and environmentally friendly. The following information is provided to help you choose the best option for your outdoor lighting needs.

Solid-State Lighting

LED light post in YonkersSolid-state light sources, such as Light Emitting Diodes (LEDs), are rapidly becoming the most popular option for outdoor lighting. LEDs represent the advancements in lighting technology as they are highly efficient and long lasting. Additionally, LEDs are not vulnerable to vibration or breakage like standard bulbs, making them better suited for use in locations such as schools, sports complexes, and parking lots.

Control systems maximize energy savings by automatically dimming or turning off lights based on time of day, traffic flow, and other factors. LEDs have the ability to be configured in control systems that are much more sophisticated than anything used previously with traditional lighting.

What to Consider When Looking to Purchase LEDs:

  • Third-party certifications to help assess a product’s quality. Look for Design Lights Consortium listed products or Energy Star® certified fixtures. Logos for these standards for qualified lighting products are located on specification sheets, which can be requested from lighting vendors.
  • Control systems to reduce unnecessary lighting. LEDs are compatible with advanced controls in ways that other technologies are not. The Design Lights Consortium lists control systems that have met their standards.

Light Pollution, Model Lighting Ordinances, and Other Environmental Impacts

Outdoor lighting has become a necessary, integral part of society. Unfortunately, light pollution can result when lighting extends beyond where it is needed. When purchasing and installing outdoor lighting, avoid:

  • Sky glow – brightening of the night sky caused by outdoor lighting.
  • Light trespass – an undesirable condition where unwanted exterior light is projected onto neighboring property.
  • Glare – an overwhelming light that causes annoyance and can impair or reduce visual performance; glare can occur when outdoor lights project in the “glare zone.”

Unlike other light sources which emit light in all directions, LEDs are a directional light source that is easily controlled and can be a solution to the issues identified above.

illustration of useful light versus light pollution
Caption: an illustration of useful light versus light pollution.

Strategies to Help Reduce Light Pollution at Night:

  • Follow Dark-Sky Association recommendations. It is desirable that all outdoor lighting be International Dark-Sky Association (IDA) compliant in order to mitigate the impact of artificial light at night. Visit International Dark-Sky Association for a list of compliant products.
  • Consider environmental zones and curfews. In areas particularly sensitive to light at night, use lower light levels and dim or turn off lights after 11:00 p.m. (*See publication 1f in the resources)
  • Use the Outdoor Site-Lighting Performance (OSP) metric when designing outdoor lighting. The OSP metric assists engineers to use lighting software to limit all three components of light pollution during the design phase of an outdoor lighting project. (*See publication 1c in the resources)
  • Consider factors in the environment that may disrupt the light. For example, fixtures should be designed to avoid interference from debris that can reduce the light’s longevity or inhibit light output, such as dirt and insects.

Another resource to help mitigate the negative environmental impacts of light is the model lighting ordinance (MLO), which was published to help communities to draft local requirements to limit light pollution. (*See publication 1h in the resources).

Outdoor Lighting Visibility and Brightness

Research has recently uncovered new information about the way people see at night. The human visual system operates differently at low light levels compared with daylight hours as it generally is more sensitive to shorter (cooler) wavelengths of light at night. Using this knowledge, engineers can design and choose lighting equipment that will improve human visual performance at night, make outdoor space appear brighter, and increase people’s sense of safety and security.

Parking lot after new lighting technologiesParking lot before using advanced lighting technologies
Caption: Light sources with different spectral characteristics used in parking lots at night. The lights in the left picture emit shorter wavelengths of light than that of the right picture.

The first step in selecting a proper light source is to determine the goals of a lighting installation, for example improving visibility for drivers to help them see objects entering the roadway such as other vehicles, people, or animals. There are guidelines that can assist in selecting light sources that will best meet the objectives while using the least amount of energy and reducing wasted light. (*See publication 3a in the resources).

Safety, Security, and Crime Prevention

One of the main reasons for outdoor lighting installation is to significantly improve safety for drivers, pedestrians, and neighborhoods. Sufficient continuous lighting is especially necessary for roadways and streets where traffic and pedestrians frequently interact.

Outdoor lighting is essential for the security of neighborhood residents as people generally feel more safe in brightly lighted areas. While research varies on how effective improved street lighting is in reducing crime, people commonly prefer well-lighted areas as they are more aware of their surroundings and can identify potential threats from a distance.

Outdoor Lighting Strategies, Tools, Codes, and Standards

Roadway lighting in YonkersThe chief organization for publishing lighting recommendations and standards in North America is the Illuminating Engineering Society (IES). The IES publishes outdoor lighting recommendations for a wide range of applications from roadways to sports stadiums. It is important to review these recommendations before beginning any type of lighting project.

Visit the Illuminating Engineering Society for up-to-date IES standards.

States, municipalities, and local communities may adopt these recommendations, or variations of them, as local codes or regulations. When planning any lighting project, it is essential to contact your local government regarding codes and standards in your area.


For more information about outdoor lighting and lighting in general, please visit the Lighting Research Center’s website. View the Illuminating Engineering Society/International Dark Sky Association model lighting ordinance.

Do you have any suggestions for new peer-reviewed articles and resources to update this page? Email suggestions to:

*All referenced resources are available for review.