Cov tiam ntawm lub qhov yog precisely vim lubtxoj kev teeb pom kev zooyuav tsum tau dhau los ntawm qhov chaw, yog li nws ob sab thiab sab saum toj raug kaw, thiab tsuas yog qhov qhib ntawm ob qhov kawg ntawm qhov av tuaj yeem tau txais lub teeb ntuj. Cov qauv tshwj xeeb no yuav ua rau qhov sib txawv ntawm qhov ci ntsa iab ntawm qhov nkag nkag thiab qhov nruab nrab. Yuav kom hloov mus rau qhov sib txawv brightness sib txawv, tib neeg ob lub qhov muag yuav muaj teeb meem pom kev sib txawv, yog li lub qhov nkag ntawm qhov seem muaj qhov sib txawv ntawm qhov pom.
In the daytime, when the driver approaches the tunnel entrance, due to the high brightness outside the tunnel entrance, the driver will see a black hole, which is a "black hole" phenomenon. Entering from a bright tunnel into a dark tunnel is dark adaptation, and the human eye cannot immediately perceive the details of the space, that is, the "adaptation lag phenomenon" occurs. This is because the dark adaptation time of the human visual system is longer than that of light adaptation. In the process of dark adaptation, the eye goes from light to dark with low sensitivity at first, then gradually increases, and finally reaches stability and clarity. Although the human eye's visual system can adapt to a huge drop in the brightness of the surrounding environment, the length of this adaptation time depends on the magnitude of the decrease in brightness. The greater the difference in brightness, the longer the adaptation will take. This means that at a certain driving speed, the greater the difference in brightness between inside and outside the tunnel, the longer the driver needs to adapt to the vision.
In the middle section of the tunnel, due to the relatively closed structure, automobile exhaust gas and dust are not easily dissipated in time, and the accumulation will form smoke, which affects the visibility of the driver. There is also the influence of mesoscopic visual effects in the middle segment. During the transition from photopic vision to scotopic vision, the spectral sensitivity of the human eye changes gradually, and the entire spectral sensitivity curve gradually shifts from long waves to short waves. The sensitivity of the human eye to yellow and red light (poor scotopic spectrum) decreases significantly as adaptive brightness decreases, while the response to green light (rich scotopic spectrum) greatly increases. This is why at dusk when the brightness is low, we perceive blue and green light in the shortwave direction to be bright. In addition, blue-green light will inhibit the secretion of melatonin in the human body, improve the body's response ability, and affect the pupil size of the human eye, which will directly affect the driver's reaction time, that is, affect the visual performance.