“In the Day I can’t see the stars because of the Sun
At night I can’t see the stars because of the Streetlight.”
— Michael Marlin
LED Streetlight technology means that we could potentially save millions of tons of carbon, and millions of dollars while still providing adequate lighting for public safety at night. But like many resource-efficiency gaining technologies, LED lighting is subject to Jevon’s Paradox — the idea that gains in efficiency lead to more resource consumption. The video here shows how energy-saving LED streetlights have led to increased light pollution.
Here’s an example of Streetlights done right — great roadway lighting, and great dark-sky protection!
Technical Information about LED Lights:
The Municipal Solid State Lighting Consortium Newsletter “The Lightpost” July, 2016. Contains an article about estimating appropriate lumen outputs for LED retrofit lighting.
Research on the Lighting Performance of LED Street Lights With Different Color Temperatures Volume 7, Number 6, December 2015 IEEE Photonics Journal.
The test on fog penetration shows as fog or haze level increases, road illuminance decreases, which means light’s transmission through fog or haze decreases. Higher CCT is correlated to lower transmission in fog or haze. When using LEDs for road lighting, the human eye has decent dark adaption time and color discrimination abilities under street lights of around 3000K CCT. LED light of 3000 K CCT also has relatively high luminous efficacy, and is suitable for road lighting.
Public Safety and Outdoor Lighting:
Chicago Alley Lighting Project: Final Evluation Report. April 2000
Analysis showed an increase in crime when lighting levels were increased .
Outdoor Lighting and Security White Paper Pacific Gas and Electric Company 2008.
“None of the papers reviewed presents sufficient evidence to demonstrate a causal link between night-time lighting and crime. The available results show a mixed picture of positive and negative effects of lighting on crime, most of which are not statistically significant. This suggests either that there is no link between lighting and crime, or that any link is too subtle or complex to have been evident in the data, given the limited size of the studies undertaken.”
“Several studies showed a significant relationship between lighting and the fear of crime, i.e. that people feel safer in lit areas. The amount of light required to reduce the fear of crime appears to be in the range of 10 horizontal lux (1 footcandle), with little increase in perceived safety above that level.”
Lighting Doesn’t Deter Crime – A Demonstration That The Claim That Brighter Lighting Reduces Crime Is Unfounded 2004.
Crime Prevention – What Works and What Doesn’t Work 2010
Is street lighting an effective approach in the reduction and deterrence of crime? The answer is inconclusive. The paucity of reliable and uniform data and the inadequacy of available evaluation studies preclude a definitive statement regarding the relationship between street lighting and crime
Some Useful online PDFs and presentations LED Streetlight issues.
A Comparison of Traditional Street Lighting Technologies and LED, presented by representatives of West Plains Engineering.
CCM Streetlight Retrofit Initiative, 2014 — A presentation developed by the Connecticut Conference of Municipalities about LED streetlight retrofits.
Welcome to the Connecticut Low-K LED Alliance Pages 