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A DOE Solid-State Lighting video about glare in outdoor lighting, featuring commentary from Ron Gibbons, Director of the Center for Infrastructure-based Safety Systems at Virginia Tech Transportation Institute.

Video courtesy of the Department of Energy

The prevalence of LED lighting has brought greater attention to the issue of discomfort produced by glare. DOE supports ongoing research to address the need for better glare metrics and characterization. The development of new metrics to describe glare can assist with product development, facilitating optimization, while also reducing negative consequences for building occupants associated with energy-efficient lighting technologies.

Glare Perception

DOE-funded research in this area includes a review of past studies on glare to help refine understanding of experimental procedures and establish recommendations.

Measuring Discomfort from Glare: Recommendations for Good Practice (Journal Article, September 2020)

An apparatus in Pacific Northwest National Laboratory’s Lighting Science & Technology Lab is designed to investigate glare perception by angle, intensity, and spectrum across the visual field. The apparatus enables human subject experiments to explore perceived glare while varying the position of the light source within the visual field (specifically near the edges or beyond the visual field), the size and luminance distribution of the light source, the background luminance surrounding the light source (specifically backgrounds that simulate nighttime conditions), and the spectral power distribution of the light source.

Standards and Specification Support

Current discomfort glare metrics are inadequate—there are many models and most are poor predictors or complex to calculate. PNNL studies inform efforts to develop improved glare metrics for better comfort and safety.

Predicting discomfort from glare with pedestrian-scale lighting: A comparison of candidate models using four independent datasets (Journal article, April 2023)

What to measure and report in studies of discomfort glare for pedestrian applications (Journal article, June 2022)

DOE research also supports the efforts of various IES technical committees exploring glare in pedestrian applications, including the Discomfort Glare in Outdoor Nighttime Environments (DGONE) committee and the Lighting for Outdoor Pedestrian Spaces committee.

This research contributed to the development of various metrics and recommended practices, including:

  • ANSI/IES RP-43-20, Recommended Practice: Lighting for Outdoor Pedestrian Spaces
  • ANSI/IES RP-43-21, Lighting for People in Outdoor Environments