Abstract
Judicious use of lamps is of profound significance to improve the internal traffic safety of tunnels. This study evaluated the biological effects of spectrum on human visual and nonvisual under mesopic vision category. According to the difference of human eyes’ response to the visual and nonvisual biological effects of different wavelengths of light radiation, a method of applying the mesopic visual spectral luminous efficiency curve to the assessment of nonvisual biological effects and blue light hazards is proposed. The results show that, in theory, under mesopic vision category, the spectrum with high correlation color temperature (CCT) and high color rendering index (CRI) has higher blue light content Z-value and has greater impact on human nonvisual effects and blue light radiation damage, but it can also provide higher human perception luminance. The visual effect detection experiment of driving in the interior zones of the tunnel is simulated in the laboratory, and the critical flicker frequency and reaction time are taken as physiological indexes. The results show that the spectrum with high CCT and high CRI corresponds to lower critical flicker frequency drop value and faster reaction time, which has a positive effect on improving driving safety. Therefore, this paper suggests that the LED with high CCT and high CRI (CCT = 6500 K, CRI2012 = 95) should be used in the interior zones of the tunnel with relatively short lighting section, and the CCT and CRI should be appropriately reduced in other road environments with long lighting section to reduce the impact of spectrum on nonvisual photobiology, so as to improve road traffic safety.
Highlights
Fatigue and drowsiness are the main causes of traffic accidents [1,2,3]
Based on the complexity of nonvisual biological effects and the particularity of tunnel lighting, this paper first selects the color coordinate Z-value of 1931 CIE-XYZ standard chroma system, circadian rhythm factor (CAF), perception luminance, and blue light hazard factor to evaluate the influence of spectrum on visual and nonvisual biological effects. e theoretical results show that the spectra with high color Journal of Advanced Transportation temperature (CCT) and color rendering index (CRI) correspond to higher Z-value, CAF-value, perceived brightness, and blue light hazard factor
When the CCT and CRI property were fixed, the reaction time decreases with the increase of luminance. is shows that when the tunnel lighting environment adopts high luminance, high CCT, and high CRI light source, the driver has a faster response when encountering dangerous situations, and the probability of traffic accidents will be reduced. e experimental results are consistent with the above theoretical results
Summary
Fatigue and drowsiness are the main causes of traffic accidents [1,2,3]. Due to the semienclosed space characteristics of highway tunnels, its visual pressure and monotonous environment are more likely to aggravate the fatigue and irritability of drivers, resulting in decreased driver alertness, inattention, and performance [4,5,6]. E lighting environment directly affects the driver’s information cognition and affects the driving safety. E driver can only obtain the visual capture information through the artificial light source [9]. Studies have shown that light provides us with visual information, and produces nonvisual biological effects that affect many physiological and behavioral processes such as emotion and activity [10]. CIE “position statement on nonvisual effects of light” on Oct. 3, 2019, clearly stated that “lighting should consider the visual and nonvisual effects of light comprehensively.” erefore, in the tunnel interior lighting settings, we should fully consider the impact of light on human visual and nonvisual biological effects, to ensure driving safety as far as possible.
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