Spectral characteristics of road surfaces and eye transmittance: effects in energy efficiency of road lighting at mesopic levels

MANZANO E. R.; PRECIADO OSCAR

Orlando Florida.

Congreso; IES Annual Conference 2016; 2016

IES Illuminating Engineering Society

In 2010 the CIE published a recommended system for mesopic photometry based on visual performance. According to this system, scenes illuminated at mesopic levels with lamps of high S/P ratio, will be perceived of greater brightness than those illuminated with lamps of a lower S/P ratio at equal photopic output. However, there could be other factors affected by SPD that, when are quantified, the final effect could be contradictory. The scope of this paper was to evaluate how road lighting is affected by the spectral road surface reflectance and by the human eye transmittance response, as people get older. Our results suggest that the benefits of considering the mesopic vision effect for luminaire sources with high S/P ratios are totally counteracted by the other two effects at a mesopic luminance between 0.68 cd⁄m^2 to 1.73 cd⁄m^2 for people between 20 and 60 years old, depending on the characteristics of the road surface.