Bright Ideas — CutByLexi

Bright Ideas for Safer Nights: Transforming Outdoor Lighting in Underserved Communities

Publication - Intern Study at CTLC
While I did not assist in the writing of the publication, I was involved in the formulation of the study and assisted in the collection and analysis of data. My study of ecology and sustainable environmental design assisted greatly in the research efforts.

My own personal thoughts and findings can be found at the bottom of the publication

Exterior lighting, predominantly powered by carbon-intensive fossil fuels during high residential usage hours, poses environmental and safety challenges when power outages leave communities in darkness for extended periods. In response, the California Energy Commission funded a sustainable exterior lighting initiative at the California Lighting Technology Center (CLTC) at the University of California, Davis to develop and demonstrate Renewable Energy and Advanced Lighting (REAL) systems.

REAL systems aim to integrate hybrid power (solar and grid), smart battery storage, advanced controls, energy efficiency and circadian lighting, specifically targeting underserved communities. The initiative addresses issues of carbon emissions, grid stress and safety concerns tied to substandard lighting in California’s underserved communities including two public parks, three apartment complexes and one small town’s public street (Figure 1).
The selected six communities are located in a disadvantaged area (score of 75 or higher) or a low-income area, according to CalEnviroScreen 4.0. Since the project aims to collect community feedback on the existing and new lighting systems and environments, each selected community has at least one community-based organization (CBO) that commits to participating in surveys, roundtables and site walks for the project’s duration. The selected communities have a variety of applications (e.g., streets, paths/trails, nonresidential hardscape, general park applications) and lighting fixture form factors (e.g., cobra head, shoebox, post top, wall pack, bollard, etc.).

Community Survey
Community engagement is central to this sustainable exterior lighting initiative as the research team focuses on developing inclusive, community-oriented relighting strategies. To support this, the preretrofit survey was disseminated by CBO partners digitally when possible and via printed surveys when needed. This survey was deployed in English and Spanish in each community and in Farsi and Russian in the communities that needed additional translations. If a community member was unable to fill out the survey, a staff member of the CBO assisted to collect responses and document them in the digital tool.

The research team at CLTC gathered community survey responses for the baseline existing exterior lighting system for each demonstration site from September 2022 to January 2024, while developing the new lighting system. Data reduction and analysis techniques were used to understand how the baseline exterior lighting systems were perceived by each community and if they would accept the characteristics and performance of the new exterior lighting systems. Data collection was the first step of a larger effort to solicit feedback from the communities, which included two surveys (pre-retrofit and post-retrofit) as well as site walks at night after the REAL systems were installed. The surveys address diverse aspects such as context about the respondent’s use of the space, lighting performance, safety and additional feature preferences. More detailed questions are discussed later in this article. At the beginning of the survey, questions provided context about participants’ familiarity with the site, which helped with analyzing the reliability of responses.

Figure 1

Pre-Retrofit Survey to Evaluate Existing Lighting Conditions
The research team developed a survey to understand each community’s experience with its existing lighting system. Examples of lighting-related questions in the survey include:

1. How would you rate the performance of the existing exterior lighting system at the demonstration site? Examples of performance categories include light levels, light uniformity, reliability, color and brightness.

2. Which one of the following statements describes the existing lighting conditions best at night? (The options included: I prefer much less light, I prefer less light, There’s an acceptable amount of light, I prefer more light, I prefer much more light, or Other.)

3. Consider the appearanceof colorful objects during the day (with daylight) and at night (with existing exterior lighting at the demonstration site). Do the colorful objects appear the same or different?

4. Please rate your visual comfort when using the exterior space at the demonstration site at night. (Indicators of visual discomfort may include squinting, headaches, averting eyes or shielding eyes when in the exterior space with the lighting system.)

5. Have you seen any unexpected exterior lighting behavior at the demonstration site? (Examples of unexpected lighting behavior may include lights turning off at night, lights flickering/ flashing/ strobing, light color changes, lights staying on during the day, etc.)

6. Have you experienced a power shutoff or power outage at night that turned off the exterior lighting at the demonstration site?

7. Please rate the visibilityat this demonstration site when you are walking at night. Consider if you can see other people walking, standing and sitting in all areas of this site while you are walking.

8. Please rate the visibility at the demonstration site when you are driving at night. Consider if you can see other people walking, standing and sitting in all areas of this site while you are driving.

9. How would you rate the safety/security at thedemonstration site when walking alone at night, concerning the existing exterior lighting?

10. Is there anything that you do not like about the exterior lights or their performance at night at the demonstration site?

Table 1 (Top) & Figure 2 (Bottom)

Results
A total of 699 completed responses were collected from the six demonstration sites across California, providing comprehensive insights into existing exterior lighting systems for three apartment complexes, two parks and one public street. To better understand how the demonstration communities responded both individually and cumulatively as a representative population of disadvantaged and low-income communities in California, quantitative analysis was performed on the filtered and categorized datasets. Descriptive statistics, inferential analyses and visualization techniques were employed to derive meaningful insights from the refined data. The research team achieved a total of 273 completed surveys at the three apartment complexes, 323 completed surveys at the two parks and 103 completed surveys at the small-town public street application (Table 1).

Analysis per Demonstration Site Type
Results per demonstration site type (apartments, parks and public street) were analyzed by the research team, contrasting the differences between site type and specific necessities from the communities.

Figure 2 shows how the different communities describe the existing lighting conditions at night. Results indicate the community preference for more light in all three demonstration site types (apartments, parks and street). Apartment complexes and the public street had more than 60% of surveyed participants asking for “Much more light.” The survey participants at the two selected parks also expressed the desire for more light, as 70% of the responses indicated that they prefer “More light” or “Much more light” at night.

One of the crucial lighting characteristics at night for pedestrians or drivers is to have the ability to recognize different colors. This measure is evaluated by color rendering index (CRI) or color fidelity (TM-30). The research team asked the community members about color recognition differences during the day under daylight and at night under the existing exterior lighting (pole-mounted outdoor lighting). Figure 3 shows that participants in all three demonstration site types agree that they cannot recognize object and surface colors under the existing street lighting compared to daylight conditions. The majority of responses were “Extremely different,” “Very different” and “Moderately different.” The public street shows the most negative responses, with 37% of participants recording a response of “Extremely different.” Apartment complexes have the most “Moderately different” replies, with 36% of participants. These results indicate that participants are, on average, more satisfied with the color rendering and color discrimination attributes of the lighting at the apartment complexes than at the public street. Participants were also asked to rate their visual comfort level at night. Visual discomfort can be identified by averting eyes or shielding eyes from light sources in exterior spaces. The majority of responses rate visual comfort as “Very Poor” and “Poor”.

Figure 3

Figure 4

Figure 5

Figure 6

(Figure 4). Surveyed participants at the public street expressed the most negative feedback with 69% qualifying visual comfort as “Very Poor” and “Poor,” contrasting with the parks, where 49% of participants responded “Very Poor” and “Poor.” For the apartment complexes, 61% of participants answered “Very Poor” and “Poor.”

Surveyed participants expressed mainly negative feedback about visual comfort at night. These results indicate that the lighting at all three applications do not provide a comfortable view of the surroundings at night.

Results Across All Site Types
Visibility challenges were reported in the surveyed communities, with “Poor” ratings for walking and driving visibility prevalent across all three site types. In addition, surveyed community members from all sites consistently expressed a strong preference for “Much more light,” revealing a widespread desire for enhanced lighting in all surveyed settings (Figure 5).

The analysis underscores a collective ask from the underserved communities for safer, well-lit community spaces across selected sites. Participants who provided feedback mainly explained the desire for more security. In total, 65% of participants expressed that safety and security are “Very Poor” or “Poor” when walking alone at night under the existing exterior lighting (Figure 6).

In the pre-retrofit survey, participants had the option to further explain their perception of safety at night. Community members expressed safety and security concerns in connection with the inadequate light levels, with a significant portion of participants feeling unsafe due to poor illumination. In total, 57% of participants shared that the lack of lighting makes them feel unsafe at night, while 25% of participants also feel that it is very dark at night. These responses indicate the communities’ preference for more lighting to improve safety and security at night.

In addition to improving the light levels, community members indicated that adding surveillance cameras and/or safety beacons to the light poles when possible is desired and reflects a shared statewide emphasis on the desire for enhanced safety features in these communities. Furthermore, reports of unexpected lighting behaviors and power outages underscore the need for improved grid resiliency. To address this, a notable opportunity emerges for REAL systems, which integrate solar and battery devices into grid-connected LED lighting, to offer a potential solution toward power outage concerns across all applications.

Next Steps
The pre-retrofit survey results highlight the diverse needs and priorities inherent in these six sites, emphasizing the importance of tailoring lighting solutions to the specific requirements of apartments, parks and public streets. The integration of advanced, low-carbon lighting technologies, coupled with a focus on improved grid resiliency, emerges as a pivotal pathway toward creating safer and more sustainable communities throughout California.

The next steps for CLTC’s sustainable exterior lighting initiative will leverage the feedback obtained from the community surveys along with existing light level measurements taken at each site. This information will be used in combination with lighting models to create customized lighting system designs for each surveyed community location. Once the designs are finalized and procured, they will be installed at each location. Following the installation, a similar survey will be administered to the community, prioritizing the same respondents whenever possible. The goal is to gather equivalent insights from the residents on their experiences with both the original and updated lighting systems.

The feedback collected from the second survey after the new system is installed, along with additional community night site walks, will play a crucial role in finalizing the commissioning of the new lighting system. By following this thorough process, the research team aims to develop and demonstrate sustainable exterior lighting systems that meet the specific needs and preferences of each community.

Personal Findings

Impacts On Local Wildlife
While the research focused on safety and effect on human population, I found that the lighting had a significant impact on the local owl population, and as a result had other impacts on the local wildlife. My study focused on the residential areas near the original research took place- North and West Davis.

The reports come from residents residing in areas where warm tone incandecent street lighting was switched to cool bright LED lights as a part of the Davis Police department to deter from crime and increase visibility.

A result of this change was the decline of owl sightings in the area. While the burrowing owl population numbers have already been dwindling in the past decade, there are still four other species native to the small city. Most notably in West Davis, the border of the population and farmland had a large owl population as a result of the congregation of vermin. The impact was collectivly stated to be almost immediate. And as a result the rat population had grown in davis. Many reports of their increased dwelling coincides with the replacement of lighting.

While human development disturbing local wildlife isn’t a new concept, I believe these findings to be important. Especially when the CTLC was in collaboration with the police in testing the difference in lighting; utilizing our light room. Similar to a vision test, the difference between warm and cold lighting does not significantly impact legibility. The change was made without accomplishing the intended purpose of detering crime. Instead it could be concluded was all we did was further remove these owls from their habitat and allowed vermin population to increase.