September 23, 2025
Authors
Executive Summary
Artificial lighting poses potential risks to wildlife that rely on natural light cues for navigation and safety, creating conflicts around the effects of urban expansion on sensitive species. As regulations and litigation evolve, site- and species-specific evaluations provide developers and communities with science-backed guidance to assess environmental impacts and inform lighting design.
Exponent's unique capabilities — encompassing proactive risk assessment and mitigation, Endangered Species Act review, building design evaluation, and expert testimony — can help stakeholders navigate compliance with shifting standards while protecting wildlife. By combining deep technical expertise with innovative methods like "turtle vision" to illustrate differences in animal and human light perception, Exponent offers a distinctive framework that strengthens defensible decision-making for legal and regulatory stakeholders.
How can property developers meet project needs while complying with regulatory and legal responsibilities to protect light-sensitive species?
The U.S. night sky is brightening by nearly 10% each year, and as urban development expands into ecologically sensitive areas, artificial light at night (ALAN) is emerging as a significant environmental and business concern. Many species rely on natural light cues for migration, reproduction, and survival, making them increasingly vulnerable to disruption. With 30% of vertebrates and over 60% of invertebrates active at night, the risks extend across entire ecosystems. For developers, the construction of hotels, condominiums, roadways, and parking lots — particularly along coastlines and in wildlife corridors — brings growing ecological scrutiny. Lighting design has therefore become a critical factor not only in environmental stewardship but also in regulatory compliance, risk management, and community engagement.
For example, beachfront lighting can disorient sea turtle hatchlings protected under the Endangered Species Act, while illuminated buildings pose collision risks for migratory birds. Offshore wind platforms, required to be lit for nautical and aviation safety, can also disrupt bat migration. These challenges have drawn increasing attention from conservation groups and regulators, fueling high-stakes disputes such as seabird- and sea turtle-related legal actions in Florida and Hawaii against coastal developers and utilities.
Beyond costly litigation, such cases carry significant economic and reputational risks for commercial property owners. At the same time, they signal a shift: a growing wave of legislation is reshaping expectations for managing artificial light at night. Forward-looking developers and asset owners who adopt science-informed lighting strategies today are better positioned to reduce legal exposure, strengthen community trust, and gain a competitive edge as sustainability and biodiversity protection become central to long-term business value.
Currently, 20 states have enacted laws to curb light pollution, with New York and Washington, D.C., adopting bird-safe building requirements that set a precedent for light-related regulation in dense urban markets. In Hawaii, lighting mitigations mandated under the Endangered Species Act target declining seabird populations, influencing municipal and roadway projects. Beyond state-level action, hundreds of municipalities nationwide have adopted outdoor lighting ordinances, as documented by an interactive map from DesignLights Consortium.
For commercial development and real estate stakeholders, this evolving patchwork of regulation underscores the need for proactive strategies. Rigorous, site- and species-specific ecological risk assessments are becoming essential not only to quantify the environmental impacts of ALAN but also to identify innovative, less-harmful design alternatives.
To effectively address the ecological and organizational risks posed by ALAN, commercial developers and real estate stakeholders can benefit from a more strategic approach to lighting and architectural design. Rigorous, site- and species-specific ecological risk assessments are becoming essential tools for identifying environmental impacts and developing less harmful alternatives.
How can design strategies help mitigate the effects of artificial light pollution?
Designing to mitigate the harmful impacts of ALAN presents a complex challenge: balancing the ecological needs of wildlife with the safety, security, and usability requirements of human environments. Meeting this challenge requires a holistic and strategic approach that integrates science, design innovation, and regulatory awareness.
The following strategies, when applied thoughtfully, can reduce the risks to nocturnal species while maintaining functionality for people. While particularly relevant to commercial development, these practices are equally applicable to government projects and infrastructure such as roadway lighting, public parking areas, and stadiums — areas where ecological impact and community visibility often intersect.
Careful lighting selection and placement
- Follow local ordinances and common industry practices to ensure compliance and effectiveness.
- Use shielded fixtures to direct light downward and away from natural corridors, minimizing stray illumination that can disrupt wildlife while maintaining necessary visibility for humans.
Advanced lighting controls
- Implement motion sensors and dimmers to keep lighting at the minimum intensity necessary for safety and security. This approach reduces unnecessary light pollution and conserves energy.
Parking lots and outdoor structures
- Integrate vegetative buffers and strategic landscaping to occlude the impact of artificial light from known wildlife nesting or migratory grounds. Trees and shrubs not only act as physical barriers to light trespass, providing essential cover and navigation cues for wildlife, but also enhance the aesthetic and functional quality of human spaces.
Architectural design
- Incorporate recessed lighting, covered walkways, and tinted windows and doors to reduce light spill.
- Orient buildings to leverage natural topography and apply glass coatings or films to shield sensitive zones, protecting both wildlife habitats and human privacy.
Wildlife-friendly lighting
- Select bulbs with optimal wavelengths to minimize impact on wildlife populations such as reptiles and birds, ensuring their natural behaviors are not disrupted.
- Opt for bulbs with longer, narrow-band wavelengths (e.g., red-orange, amber LED bulbs) to better accommodate nocturnal animals.
- Keep bulb luminance as low as possible while maintaining sufficient lighting for human activities.
Through the implementation of smart design, project teams can navigate the complex challenge of designing spaces that protect wildlife and ensure human safety, creating environments that are both ecologically responsible and secure.
In some cases, existing design elements may already reduce light pollution, potentially enabling cost-saving adjustments to ordinances or practices.
How can technical experts support evolving ALAN-related litigation?
Despite best efforts, disputes can still arise when ordinances or regulatory language are ambiguous, misinterpreted, or when compliance — or the impact of ALAN on wildlife — is challenged. Projects that follow approved standards may still face scrutiny from wildlife advocacy groups, and property owners can encounter light pollution — related lawsuits, resulting in potential liability, added expenses, and project disruptions. In such cases, stakeholders can benefit from assessing the actual impacts of lighting and identifying site-specific mitigation strategies that support both wildlife conservation and human activities.
Comprehensive ecological assessments
A multidisciplinary approach is essential for understanding the complexities of light pollution and its effects on wildlife. Rather than relying on general studies, Exponent focuses on site- and species-specific analyses. These risk assessments may include evaluating species-specific behavioral data, conducting surveys and field observations, and examining the lighting environment in detail. This approach allows for characterization of the numerous light-related factors affecting wildlife optical receptors, assessment of the relative importance of each factor, and ultimately, the identification of species-specific risks based on the collected data.
Balancing conservation and development
Findings from these assessments can guide targeted lighting adjustments that support conservation goals while addressing the unique lighting impacts of a specific site. In some cases, existing design elements may already reduce light pollution, potentially enabling cost-saving adjustments to ordinances or practices. In other situations, science-based measurements of light levels and pollution can be collected on-site, with design iterations informed by advanced modeling software or physical testing, ensuring both ecological protection and functional lighting performance.
Navigating regulatory challenges
Navigating environmental regulations can be complex. Stakeholders must ensure that solutions are both scientifically sound and legally compliant, balancing ecological needs with human and economic considerations. Leveraging scientific and design expertise can help demonstrate gaps between proposed solutions and real-world effects, particularly when regulatory guidelines are not fully evidence based. In certain cases, variances may be sought when supported by site-specific conditions and lighting designs.
In environmental disputes that escalate to litigation, regulatory hearings or public meetings, objective and unbiased technical experts play a critical role in presenting complex scientific findings. These experts must communicate their conclusions clearly to judges, juries, arbitrators, and stakeholders. When cases hinge on nuanced scientific evidence, strategically combining expert reports, verbal testimony, and compelling visualizations — grounded in rigorous analysis and presented in accessible language — can be decisive. For example, Exponent's team of ecological and multidisciplinary scientists translates technical data into clear visual tools, such as our recent effort to convey "turtle vision," which demonstrated how light is perceived by sea turtles versus humans, readily highlighting the differences in their photoreceptors.
Side-by-side comparisons and visual aids are particularly effective in helping legal decision-makers quickly understand complex concepts — for example, why certain lights that appear bright to humans, such as amber lighting, are nearly imperceptible to sea turtles. These insights can play a critical role in determining liability in coastal development cases, showing the value of bridging science, design, and law as ALAN-related litigation and environmental regulations continue to expand.
Frequently Asked Questions
What Can We Help You Solve?
Exponent leverages expertise in ecological and environmental science, electrical engineering, regulatory frameworks, and risk assessment to support clients facing the multifaceted challenges of light pollution through science-based design reviews, mitigation plans, and dispute support. We help clients interpret and meet standards and provide technical guidance for sustainable development initiatives.
![[EBS] Ecological & Biological Sciences - Environmental Risk Assessment - grey heron grazing in fresh water](/sites/default/files/styles/cards_home_card/public/media/images/grey-heron-2022-01-04-23-54-37-utc%281%29_0.jpg.webp?itok=5EB0lXjA)
Environmental Risk Assessment
Risk assessments for legacy spills and contamination, potential project and product impacts, and environmental remediation support.
Environmental Permitting
Extensive support for compliance with local, state, and federal permitting requirements.
Power Electronics
Advice for all aspects of power electronic systems to help you plan your power processes.
Modeling & Analysis
Experienced environmental analysis and data modeling for a range of complex environmental challenges.
