The influence of spectral properties of light in street lighting on visual perception

Light formed through urban morphology and different organism groups: First findings from a systematic review.

“…Existing knowledge related to urban lighting design considers various factors and impacts, e.g., perceived light qualities from a human perspective [56] and physiological and behavioural alterations on species [15]. Few studies concentrate on the interaction between spatial characteristics and lighting [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38]; others focus exclusively on either human vision [39][40][41][42][43][44][45][46][47][48][49][50]62], perception [51][52][53][54]58] or environmental impacts [12-15, 59, 61, 64]. Thus, the overall knowledge on the contribution of spatial characteristics in transforming the light effects in urban contexts, impacting pedestrians and ecology, appears fragmented and not holistically integrated.…”

“…Visual perception is influenced by light source characteristics, the properties of object surfaces that the light reflects from, and the receivers and their visual system [39]. Cone photoreceptors in the eye facilitate detail and colour vision at high light levels (photopic vision) and guidelines and tools for outdoor lighting systems [40].…”

“…Cone photoreceptors in the eye facilitate detail and colour vision at high light levels (photopic vision) and guidelines and tools for outdoor lighting systems [40]. Light levels of 3-5 cd/m 2 are the threshold for mesopic vision, meaning that cone vision decreases with lowering light levels, and the rod photoreceptors become active [39,41]. Rods are the photoreceptors that enable low light, scotopic vision at levels lower than 0.001 cd/m 2 .…”

“…While these mechanisms have been known, and the scotopic to the photopic ratio (S/P ratio) is an established measure to evaluate the ability of light to support low-light vision, there is no agreement on designing lighting for the urban and suburban outdoors [42][43][44]. Early models proposed look-up tables for factors to adjust photopic luminance to mesopic [44], but one of the complexities is that the spectral sensitivity of low light vision changes with light levels [39]. Researchers have explored mesopic vision models to digitally simulate visibility in responses to different light spectra and light levels [43] and related affective responses.…”