Statement from the Thomas Hart Benton Sierra Club Legislative Committee:
The view of the Universe itself, which can only be seen at night, is a magnificent sight. Excessive lighting from many sources, including streetlights, washes out this view. Artificial light at night from next generation LEDs has greatly expanded in recent decades. Even more recently, scientific advances have improved our understanding of the impact of artificial light on the natural world generally and harmful impacts from improperly selected LEDs specifically. Kansas City’s LED streetlights were selected without consideration of the scientific consensus that these unintended harmful impacts can be greatly reduced by using only the amount of light needed. Instead, Kansas City’s proposed system multiplies national illuminance industry standards. It is the purpose of this document to introduce, in everyday terms, potential impacts on the urban ecology and to suggest mitigation strategies that have been successful in other cities. Kansas City’s proposed streetlight system will be referred to as “the proposed system” throughout this document.
Kansas City is a “late adopter.” Many other cities in the metro area and throughout the U.S. (“early adopters”) have already converted to LED streetlights. A wealth of lessons and knowledge from other cities on best practices were not incorporated into the proposed system. One example is Phoenix, Arizona – similar to Kansas City in size and number of streetlights. Their streetlight system is a model of sustainability that could be replicated. Instead, Kansas City’s proposed system is a high-luminance, relatively inefficient system planned without environmental considerations. It is similar to unpopular systems installed by “early adopter” cities and later changed due to resident demands.
This image is from Nature.com
What are the Advantages of light emitting diodes (LED) over High Pressure Sodium (HPS) streetlights?
⦁ LEDs are superior technology and provide improved visibility.
⦁ LEDS are more economical and energy efficient, last longer and require less maintenance.
⦁ LEDs are dimmable, which confers lots of advantages to municipalities, residents, and the natural environment.
⦁ Just as there are soft LED streetlights that have been well-received by residents, there are harsh streetlight systems, similar to the proposed system, that have been rejected by residents in other cities.
What is the color temperature of streetlights?
LED streetlights range from amber, (2200K) – the same as our current streetlights) to warm white (3000K) to cool white (4000K) and beyond. This chart shows the wavelengths of various sources of light. Lights with strong emissions in the blue spectrum have a high color temperature and shorter wavelengths. At the time of this writing, the color temperature for the proposed system has not been announced. (see below).
What is the status of the proposed system?
- The city has installed 6,768 (4000K) LED streetlights in 8% of the city. There has been no installation of 3000K LED streetlights to allow for a comparison.
- February, 2021 - Kansas City announced that the remaining 92% of city streetlights will be replaced with LEDs. and solicited proposals.
- March, 2021 - two sets of project bids were received from contractors. For reasons described below, our committee advocated that the color temperature not exceed 3000K. The city then asked contractors to submit two separate Base Bids. City staff will make the final decision about the color temperature. At the time of this writing, it is believed they are considering 3000K in residential areas and 4000K on the wider, arterial streets. Residents and municipalities across the U.S. are finding that LEDs with a color temperature in excess of 3000K are objectionable, no matter their street location.
- Base Bid #1 and Base Bid #2 - replace 83,913 (all remaining sodium streetlights) with 3000K LED and 4000K LED respectively. Each contractor quoted an equal price for Base Bid 1 and Base Bid 2. There is also no difference in energy use between these two color temperature LEDs. Base bids varied among Contractors from around $20 - $34 million dollars.
In addition to these Base Bids, there were 4 alternates. The city will select a contractor for one base bid and retains the option of whether to include alternates in any future contract.
- replace 6,768 existing LEDs with 3000K
- provide GPS data on all poles.
- mesh adaptive photocontrols remotely managed by Contractor for 8 years
- cellular adaptive photocontrols remotely managed by Contractor for 8 years.
Why Stay Below 3000K?
- reduces skyglow
- Cities with public participation and/or demonstration projects, selected 3000K and lower
- higher color temperatures are experienced as harsh.
- Blue light from LEDs increases as the coatings degrade over time
- higher color temperature LEDs create more glare, a traffic safety concern
See this link for more info: LED: Why 3000K or Less | International Dark-Sky Association
What impact will the proposed system have on the environment?
- Carefully and intentionally designed LED systems can mitigate increased light pollution. Increased skyglow can be mitigated as much as half by installing 3000K or lower compared to 4000K lights.
- The proposed system will have a long-term, harmful impact on nocturnal wildlife and bird migration.
- LED luminaires can last 15 years or longer, so it will be a long-term impact
- LED streetlight conversions typically result in energy savings of 50% or more, but, because Kansas City uses an “illuminance multiplier”, the proposed system will save about 46%.
How does artificial light at night harm migrating birds and wildlife?
- All living beings, not just humans, depend on a regular interval of daylight and darkness for proper functioning of behavioral, reproductive and immune systems. Disruption to these systems causes well-documented, cascading impacts.
- The eyes of nocturnal animals are specially evolved for low-light conditions, and small changes in illumination can profoundly alter foraging patterns and success. Many of these beneficial species mostly eat rodents and insects, which are agricultural pests, so we’d like to keep the beneficial species around.
- Light spectra and photoperiods are the tuning fork for nature. Light provides all animals with cues on when to hibernate, optimal timing for reproductive success and other evolutionary survival strategies for their species. Excessive luminance from the proposed system disrupts these key behaviors. These harmful impacts can be mitigated by selecting lower color temperature lighting and using only the amount of light needed.
- Kansas City is a 320 square mile city located on the “Mississippi flyway”, a major flyway in North America used by migratory birds at night. Light pollution interferes with navigation of migratory birds. For more information, please click here.
How does the proposed system compare with other cities?
- Many cities and states have already completed streetlight retrofits.
- Denver, Salt Lake City, Phoenix, Tucson and many other cities are committed to LED streetlights with color temperature 3000K or lower on all street types.
- Salt Lake City, Utah – new LED streetlights are twice as energy efficient as Kansas City’s planned system.
- On a scale of 0 (no glare) to 5 (glare that can cause traffic safety issues), KC’s proposed luminaires for six-lane roads, have a Glare rating of 4 compared to 2 for the same road type in Salt Lake City.
- No resident input has been systematically and meaningfully solicited for Kansas City’s project. Washington, DC convened a Streetlight Advisory Panel made up of community representatives that meet regularly to discuss key issues.
Why are Chicago, Los Angeles, Seattle, Denver, Washington DC and New York City and other large cities changing streetlights from higher to lower color temperatures?
There is growing awareness of the impacts of artificial light on the natural environment and wildlife. In 2016, the American Medical Association recommended that cities not exceed 3000K LEDs for streetlights. As residents learn of the harmful effects of higher color temperature lights, they demand change.
Why have none of the cities that started with lower color temperatures, (2700 – 3000K) changed to higher?
- Residents like the softer light and appreciate that it reduces harmful impacts on wildlife and bird migration.
Which streetlights are safer from a traffic safety perspective?
- With night vision, the eye calibrates to the brightest light within the field of view. LEDs have the potential to impair vision for both drivers and pedestrians, like having a flashlight shining in your eye. Both disability glare and discomfort glare can potentially decrease traffic safety. For this reason, lighting experts recommend that streetlight luminance should not exceed the national standard, (ANSI/IES Recommended Practices-8-18).
- The proposed system for Kansas City exceeds the ANSI/IES national standards by as much as 1.5 times the recommended luminance.
- There are no peer-reviewed studies that show safety improves with higher color temperature of streetlights. There is also no evidence that the millions of drivers in other cities with lower color temperature streetlights, have a higher rate of accidents. In fact, Denver, with 3000K, has a successful safety education program to reduce traffic deaths.
- High-glare systems, like the one proposed in Kansas City, may decrease detection of objects in the roadway.
- Glare increases with color temperature.
Why does Kansas City use an Illuminance Multiplier? Why can’t we just follow national illuminance standards?
- Well-designed LED lighting improves both visibility and uniformity over the current sodium lights, which has led to assertions that the proposed system will reduce crime. However, streetlights are not a magical short-cut to reduce crime. Crime is influenced by a combination of factors, including effective policing, community services and improved economic opportunities such as increased wages.
- Bright lights create dark shadows. An object that would be visible in dim light may not be visible when a high-lumen LED is within the field of view.
- Houston is an early adopter city, with high-lumen LEDs similar to the proposed system, yet crime rates and pedestrian fatalities are increasing.
- The proposed system is a One Size Fits All system. The only variances in illumination are based on street width. However, the extreme illumination levels are inappropriate for many areas.
- Blue light is correlated with sleep disorders, juvenile delinquency and negative health impacts for all living beings, including people. The illuminance multiplier essentially creates an urban self-experiment, increasing exposure to blue light, even if the 3000K color temperature is selected. With the illuminance multiplier in place, and without dimming, Kansas City should not exceed color temperature of 2700K for any street type.
- People will close their window shades to keep out the unwanted light, reducing neighborhood awareness.
For more information, see: Lighting, Crime and Safety | International Dark-Sky Association
What are the Advantages of a dimmable system, and what is the most cost-efficient way to do this?
- In 2016, the American Medical Association recommended dimming of streetlights during off-peak periods for human health and environmental benefits.
- Dimming extends the life of luminaires, increases energy savings and benefits the environment.
- stand-alone, dimmable, snap-on photocontrols are available for 1/3 the cost of remotely operated controls, and are easily re-set for different times if needed. (Remotely operated systems, like the ones considered by Kansas City, rely on wireless connectivity. These “adaptive controls” are so complex they require electronics specialists to operate them, increasing costs.)
- Dimming is gradual and typically not noticeable.
- There is no traffic safety impact with dimming of streetlights (U.S. Department of Transportation).
- Cities such as Tucson, Arizona, dim most lights after midnight. Areas with higher pedestrian traffic are dimmed from 3 am to 5 am.
What does the Thomas Hart Benton Sierra Club Legislative Committee Recommend?
- The proposed system must strike a balance with the needs of the natural environment and the human environment. Residents want the best system for human health, traffic safety, economy and for the natural environment. The proposed street light system for Kansas City should include the following:
- Reduce excessive luminance by adding stand-alone dimmers that don’t rely on remotely operated wireless electronics.
- Learn from the lessons of other cities, where streetlight projects have been met with complaints from residents.
- Incorporate these April 2021 recommendations from the Kansas City Environmental Management Commission:
- Provide for demonstration of the variance between color temperatures (Kelvin factor) as well as the intensity of the lighting (more is not always better) and solicit public input regarding the desirability of the available choices.
- For the long term, include dimming capabilities to respond to specific area conditions or preferences and realize additional energy and cost savings during times and in locations where lower illumination is preferred.
Which LED streetlights will Kansas City officials choose?
Optimum Streetlight Plan
Model of Sustainability - Phoenix & other cities
Clunker Streetlight Plan
Similar to Plan
Proposed by Kansas City
Meets illuminance standards
Brightness exceeds national standards
Easier for the human eye
to see at night
More difficult to see at night
No harsh glare
Warm, beautiful lights
Color temperature 3000K or below
Bright lights make dark shadows
Color Temperature 4000K
Embraced by residents in Tucson, Phoenix, Denver and elsewhere
Rejected after installation by Chicago, New York City, Los Angeles, Seattle and Washington DC
Always favored when residents are included in the process
“Even the people look better.”
Not favored by residents
“sewage treatment plant atmosphere”
Less skyglow helps migrating birds
80% of migrating birds migrate at night
More skyglow contributes to declines in bird populations by attracting
birds to cities
Benefits nocturnal species that eat rodents and insects
attracts insects to our yards
(the ones that eat our crops)
Stand-alone pre-set dimming
Remotely controlled dimming
twice as expensive
Most energy efficient
Not as energy efficient
Please contact your city Councilperson to ask that residents be included in the selection, in an equitable manner, and that migratory birds and urban wildlife be considered in the design.