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Glare in LED Outdoor Lighting

Many of the applications where SSL has experienced rapid adoption have incumbent light sources with high brightness and glare potential, such as high-intensity discharge lamps for street and parking lot lighting and halogen lamps for PAR and MR applications. The inherently high brightness and small size of LED sources create significantly higher glare potential compared to incumbent technologies, and this concern will only worsen as SSL sources achieve higher output at higher efficacy. To help address this issue, DOE technical support includes involvement on several related committees, and plans to initiate new human factors research in the near future. Current committee involvement includes:

  • CIE JTC7, Discomfort Caused by Glare from Luminaires with a Non-Uniform Source Luminance, which is in the late stages of producing an improvement to the Unified Glare Rating (UGR) that takes the luminance distribution across the face or aperture of a luminaire into account in the UGR calculation
  • CIE TC4-52, Lighting for Pedestrians: New Empirical Data
  • IES Lighting for Outdoor Public Spaces, which focuses on the specific needs of pedestrians in outdoor spaces, recognizing that glare for pedestrians is significantly different from the needs of vehicle drivers

In addition, DOE mock-up investigations will explore the position of a glare source within the visual field (specifically near the edges or beyond the visual field), the size and luminance distribution of the glare source, the background luminance of the light source (specifically backgrounds that simulate nighttime conditions), and the effect of the spectral power distribution of the glare source.