## 1 Introduction  
China's process of highway construction is gaining momentum, leading to an increase in the scale and number of highway tunnels [1]. Consequently, the scale and number of tunnel lighting facilities are also on the rise. This expansion, however, brings with it certain challenges, such as a noticeable increase in energy consumption due to tunnel lighting and a rise in the rate of traffic accidents. Tunnels oriented from east to west are relatively common in current construction projects, yet they also present their own set of problems. Due to the particularity of the direction of the east-west highway tunnel and the trend of the sun rising in the east and setting in the west, the brightness outside the tunnel near the tunnel is larger in the morning (afternoon). Therefore, the luminance difference between inside and outside the tunnel is large and the resulting glare phenomenon is caused. The phenomenon of glare in the access zone will increase the driver's visual burden and prolong the driver's identification and judgment time of tunnel road conditions, which will readily cause the driver to be unable to accurately judge the road conditions ahead and thus generate safety risks [2]. Disability glare is a physiological term that is caused by distracting light from a glare source scattering onto the surface of the retina, like a large screen on the retina, reducing the contrast of images on the retina, resulting in reduced visibility [3]. During the driving process, poor luminance distribution in the driver's field of vision causes glare problems, thus negatively affecting visual perception [4]. The access zone of a road tunnel refers to the length of the stopping sight distance for one time outside the tunnel entrance. As the transitional adaptation section is before the driver enters the tunnel, the safety of the access zone is particularly important. L\({}_{20}\)(S) is a key index for studying the external luminance of the tunnel in the access zone. L\({}_{20}\)(S) represents the average luminance of a 20\({}^{\circ}\) conical field of view when an observer at the start of the access zone looks towards a central point located at one quarter of the tunnel portal height. Scholars have carried out a series of studies on the L\({}_{20}\)(S) outside the tunnel and the glare phenomenon in the access zone of the east-west oriented road tunnel, and have obtained certain results. Reference [5] measured 12 real tunnels, and it was concluded that the L\({}_{20}\)(S) of the east-west oriented tunnel is smaller than the north-south oriented tunnel. [PERSON] [6] in combination with different tunnel orientations, concluded that the sunlight of the tunnel facing east in the morning and that of the tunnel facing west in the afternoon is stronger and the luminance outside the tunnel is larger, which is extremely unfavorable to traffic safety near the tunnel. [PERSON] [7] believed that the main reason for the safety problems in the access zone of the tunnel was the \"black-hole effect\" in the threshold zone, that is, the visual blindness period in the threshold zone. In the field of tunnel lighting, the research on glare in road tunnels has mainly focused on the road lighting and automobile lighting, and the glare threshold increment TI and glare control level G are mainly used as the guiding standards for highway lighting design [8]. [PERSON] et al. [9] believe that asphalt pavement with a low reflection coefficient should be used in the tunnel approach section to reduce the external luminance of the tunnel, to improve the \"black-hole effect\" in the tunnel approach section. [PERSON] et al. [10] analyzed the influence of central divider greening on the anti-glare effect. By comparing the anti-glare structures of different tunnel doors, [PERSON] et al. [11] concluded that the shading shed at the tunnel entrance can not only solve the transition problem of road dimming, but also achieve the effect of anti-glare. [PERSON] [12] et al.