Safety Evaluation of the Lighting at the Entrance of a Very Long Road Tunnel: A Case Study in Ilam

Abstract

BackgroundAt the entrance of a tunnel, reflection of sunlight from the surrounding environment and a lack of adequate lighting usually cause some vision problems. The purpose of this study was to perform a safety evaluation of lighting on a very long road in Ilam, Iran.MethodsThe average luminance was measured using a luminance meter (model S3; Hagner, Solna, Sweden). A camera (model 108, 35-mm single-lens reflex; Yashica, Nagano, Japan) was used to take photographs of the safe stopping distance from the tunnel entrance. Equivalent luminance was determined according to the Holliday polar diagram.ResultsConsidering the average luminance at the tunnel entrance (116.7 cd/m2) and using Adrian's equation, the safe level of lighting at the entrance of the tunnel was determined to be 0.7.ConclusionA comparison between the results of the safe levels of lighting at the entrance of the tunnel and the De Boer scale showed that the phenomenon of black holes is created at the tunnel entrance. This may lead to a misadaptation of the drivers’ eyes to the change in luminance level at the entrance of the tunnel, thereby increasing the risk of road accidents in this zone.

Assessment of contrast perception of obstacles in tunnel entrance

“…9 , 19 Safe stopping distance depends on several factors, including road gradient (upward or downward; ± s , %), passing vehicle speed limit ( U , m/s), driver reaction time ( t 0, s), acceleration due to gravity ( g , m/s 2 ), and the coefficient of friction between the tire and the road ( f , dimensionless). 1 Eq. 2 is used to calculate the SSD.…”

“…Road traffic accidents that occur in tunnels make up a small percentage of road accidents, but with enormous consequences. 1 , 2 In the meantime, the accident rate in the entrance zone of tunnel is so high compared to other areas; such that the Norway Highway Bureau reported that about 63.7% of tunnel collisions occur at entrance zones. 2 Many studies have suggested that the visual features for drivers approaching a tunnel entrance are crucial factors to assess the risk of crash related to tunnel travel.…”

“… 2 Many studies have suggested that the visual features for drivers approaching a tunnel entrance are crucial factors to assess the risk of crash related to tunnel travel. 1 , 3 They indicated that difficulty in the visual adaptation of drivers caused by dark environment inside the tunnel is an important factor in this regard. 4 , 5 …”

“…The aim of this study was to assess the contrast perception of obstacles in a tunnel entrance which was placed in Ilam, Iran and also assess the effects of luminance (equivalent veiling luminance, car windshield luminance and atmospheric luminance) on perceived contrast of the obstacle in the tunnel entrance. The characteristics of studied tunnel have been described in the study of Mehri et al 1 …”

Evaluation of the Combined Effects of Heat and Lighting on the Level of Attention and Reaction Time: Climate Chamber Experiments in Iran

“…Adequate lighting will make the employees produce more products with less error, leading to a 10–50% increase in productivity and efficiency of the employees [ 17 ]. Therefore, undesirable environmental conditions such as exposure to inappropriate heat and light will influence human error, the occurrence of accidents, and productivity level through the adverse effect on cognitive performance such as attention, concentration, and reaction time [ 11 , 18 ].…”