Parking Lot Lighting - Learning Objectives

1. What are the most important considerations when lighting a parking lot?
2. Perceived safety.
3. How to support Dark Sky?

Cooler parking lot lighting increases perception of safety. 

"Brightness Perception, CCT, and Safety Additional studies have demonstrated that perceptions of safety are correlated with perceptions of how bright the overall lighted scene appeared. Perception of scene brightness is influenced by short-wavelength (blueish-white) light; light sources with a higher correlated color temperature (CCT) will tend to have greater short-wavelength output. Spectral sensitivity for scene brightness has been successfully modeled in the laboratory (Rea et al. 2011), and validated in the field (Rea et al. 2017). Parking lots illuminated with higher CCT sources are judged to be brighter and safer than those with lower CCT sources."
https://www.lrc.rpi.edu/programs/energy/pdf/ParkingLotLightingGuide.pdf

In residential neighborhoods, IES and IDA recommend warmer wavelengths providing better circadian balance for neighbors and wildlife.

April 16, 2020 ​IDA and IES announce strategic collaboration to advance quality lighting to reduce light pollution.​ “By following these simple principles, electric lighting at night can be beautiful, healthy, and functional. These principles work together to reduce light pollution, save energy and money, and minimize wildlife disruption,” said Ruskin Hartley, Executive Director of IDA.
“Following these Principles is not difficult and results in more effective and comfortable lighting installations.”said Brian Liebel, Director of Standards and Research for the IES. [1]

This link is to a PDF on how to light your residence with Dark Sky best practice: ​https://idsw.darksky.org/wp-content/uploads/2020/04/Dark-Sky-Friendly-Home-Lighting-program-guide_Print.pdf

When we use carefully aimed, dimmer lights - instead of excessively bright, glaring ones - we can see better, maybe even see the stars.  Balance and restraint is the key to most things in life, and restraint also applies to lighting, especially in our night sky.
Visit my Dark Sky page at TOlighting.com

How could the sky at night be anything other than dark? It seems like an easy question, until you look up and try to see the Milky Way in or near a large city.

If you want to see stars, you need a dark scene free from overhead lights and free from light pollution.

Light Pollution is the name for any light that is unwanted or uncontrolled showering wasted light into the sky. Reflected light from pavement and buildings is also contributing to light pollution.

Direct Glare from unshielded light sources reduces visibility in addition to requiring your eyes to adapt between bright and dark scenes, especially difficult for seniors and those with visual impairments. As we age the time it takes for our eyes to adapt from bright to dark, or dark to light, increases.; therefore, illumination without direct glare from seeing the light source is preferred.

Dark Sky Lighting Fixtures
Luminaire Shielding Designs

This illustration shows the many types of outdoor lighting fixture designs that shield the light on the top and sides. This type of luminaire  is considered 'dark sky friendly.' to find a list of International DarkSky Association (IDA) approved fixtures visit their website. http://www.darksky.org/www.darksky.org/

How to support Dark Sky?

International Dark Sky Organization www.darksky.org
Find a chapter near you and learn more.

Become a citizen-scientists to measure & submit your night sky brightness observations.

https://www.globeatnight.org/   In 2017 citizen scientists from around the world contributed 15,382  data points.   Globe at Night is a program of the National Optical Astronomy Observatory, the national center for ground-based nighttime astronomy in the United States, operated by the Association of Universities for Research in Astronomy (AURA), under cooperative agreement with the National Science Foundation.
https://www.globeatnight.org/

Be sure to read the article about Davis LED Retrofit Zombie Lights, By James Benya

Related Topics

 Dark Sky & Light Pollution, Dark Sky Reserves, Dark Sky Ordinances,  Dark Sky & the Ecology of Night Lighting,   Astronomy & Dark Sky,  Circadian System; 

Footnotes

1. Sierra Club https://www.sierraclub.org/sierra/2018-2-march-april/feature/hunt-for-stars-dark-skies-preserves-and-parks
   

Photo Credit

• Light to Protect the Night - ​With Permission IES & IDA - https://ies.informz.net/InformzDataService/OnlineVersion/ind/bWFpbGluZ0luc3RhbmNlSWQ9MjkzNzEyMCZzdWJzY3JpYmVySWQ9Mzc3OTk3NDk5
• Luminaire Shielding Designs
  Image courtesy of Bob Crelin