June 24, 2025
701 Laurel St
Menlo Park, CA 94025
Sierra Club Loma Prieta Chapter Comments Regarding June 24th City Council Agenda Item E2. Award a construction contract to NAAC Construction, LLC and appropriate $204,604 from the General Fund unassigned balance for fiscal year 2024-25 for the High Voltage Streetlight Conversion Project
Dear Mayor Combs and Menlo Park City Councilmembers,
The Sierra Club Loma Prieta Chapter has engaged with light pollution reduction policies, also known as Dark Sky policies, in multiple cities in Santa Clara County. We have provided research and model language for Dark Sky ordinances adopted in Cupertino and Los Altos, and have worked closely with Palo Alto to influence the language in their Dark Sky ordinance slated for adoption this year.
We believe the High Voltage Streetlight Conversion Project is an opportunity to reduce light pollution in Menlo Park while conserving energy resources with the use of Dark Sky techniques and fixtures. Please provide direction for the following resources to be considered and implemented in this update process.
The Five Principles For Responsible Outdoor Lighting1. Developed by DarkSky International (IDA) and the Illuminating Engineering Society (IES), these principles outline the foundation for successful light pollution reduction.
Useful. Use light only if it is needed. All light should have a clear purpose. Consider how the use of light will impact the area, including wildlife and other habitats.
Targeted. Direct light so it falls only where it is needed. Use shielding and careful aiming to target the direction of the light beam so that it points downward and does not spill beyond where it is needed.
Low Level. Light should be no brighter than necessary. Use the lowest level light required. Be mindful of surface conditions, as some surfaces may reflect more light into the night sky than intended.
Controlled. Use light only when it is needed. Use controls such as timers or motion detectors to ensure that light is available when it is needed, dimmed when possible, and turned off when not needed.
Warm-Colored. Use warmer color lights where possible. Limit the amount of shorter wavelength (blue-violet) light to the least amount needed.
The Model Lighting Ordinance Street Lighting Ordinance. Developed by DarkSky International (IDA) and the Illuminating Engineering Society (IES), this ordinance provides guidance for jurisdictions looking to create policies for street lighting. We recommend that Menlo Park consider these standards when choosing replacement fixtures. This ordinance is attached to our email as a separate document.
DarkSky International’s Approved Products2. This curated list of luminaires contains products from a variety of categories of lighting, such as street, parking lot, roadway and security lighting. These fixtures were designed to be safe, functional, and compliant with the Five Principles for Responsible Outdoor Lighting.
Light pollution is a cumulative issue that affects living beings with circadian rhythms, humans included. DarkSky International’s 2025 State of the Science Report has summarized the findings of scientific literature:
“ALAN [artificial light at night] exposure has effects on the entire life cycle, from childhood and adolescence to old age. In particular, these effects seem to result from shortwavelength (“blue”) light. While exposure to blue light during the day is important for healthy circadian functioning, exposure to this light at night can disrupt the circadian rhythm. This can affect everything from the timing of hormone release in the body to the duration and quality of our sleep, increasing systemic inflammation and potentially resulting in adverse health outcomes. The significance of these effects depends on the intensity of light, the proportion of blue light, and the timing and duration of the exposure. Research now points to lighting approaches that can reduce the impact of ALAN on circadian rhythms.”3
As an example, a 2018 study4 in Spain analyzed the impacts of ALAN on thousands of people over a five year period. The study concluded that “both breast and prostate cancer were associated with high exposure to outdoor ALAN in the blue-enriched light spectrum.”
Furthermore, many animals are negatively impacted by light pollution. Birds are especially vulnerable since most species migrate at night.5
Lights with lower color temperatures, (typically below 3000K) in addition to being healthier for humans, are better for wildlife because they have less impact on the natural behaviors and activities of nocturnal animals.6 Nocturnal animals such as bats, and many birds and insects rely on natural light cues to navigate and complete essential functions such as feeding, breeding, and migration. Artificial light sources with higher color temperatures (typically above 3000K) can interfere with these natural cues, disrupting the animals' circadian rhythms and affecting their behavior. For example, high-color-temperature lights can attract insects, which in turn attract birds, bats and other animals that feed on them, leading to changes in insect populations and affecting the ecosystem. Additionally, high-color-temperature lights can cause birds to become disoriented during migration,7 leading to collisions with buildings and other structures. Lights with lower color temperatures are less disruptive to wildlife because they produce light that is closer in color to natural moonlight and starlight. This can help minimize the impact of artificial light on nocturnal animals and allow them to carry out their natural behaviors without interference.8
Light pollution is a cumulative issue with potentially serious negative impacts on wildlife and public health. This project is an opportunity to reduce light pollution. We hope you consider the three resources we have shared, and provide direction to include them in this streetlight conversion project.
Sincerely,
Dashiell Leeds
Conservation Coordinator
Sierra Club Loma Prieta Chapter
1 https://darksky.org/resources/guides-and-how-tos/lighting-principles/
2 https://darksky.org/what-we-do/darksky-approved/darksky-approved-luminaires-program/luminaires/
3 https://darksky.org/news/state-of-the-science-2025/
4 https://pubmed.ncbi.nlm.nih.gov/29687979/
6 Effects of LED Lighting on Terrestrial Wildlife. 2023. State of California Department of Transportation Technical Report. Prepared by Travis Longcore, Ph.D., UCLA. US Department of Fish and Wildlife. Threats to Birds: Collisions - Nighttime Lighting Protecting our Night Skies for Birds.
7 L.S.A. Huson 2021. Spatiotemporal effects of artificial lighting on migratory birds