Assessment of contrast perception of obstacles in tunnel entrance

Abstract

Background: The purpose of this study was to assess the contrast perception of obstacles in a tunnel entrance which was placed in Ilam Province, Iran.Methods: An obstacle with the reflection coefficient of 20% was mounted at the entrance of thetunnel and then, the car was placed near the tunnel entrance and the intrinsic luminance of the road (Lr,intrinsic) and obstacle (Lo,intrinsic) were measured inside the car using the luminance meter.Results: Intrinsic luminance of obstacle and road at the entrance of the tunnel were measured as 41 and 17 cd/m2, respectively. The contrast perception of obstacle in deriver’s eyes and in the safe stopping distance (SSD) from the tunnel entrance was determined as 2.79 cd/m2. At the entrance of the studied tunnel, the contrast perception of obstacles with the reflection coefficient of 20% was lower than the minimum contrast perception (28%) recommended by International Commission on Illumination.Conclusion: The main conclusion that can be drawn from it, is that this obstacle in the SSD from the tunnel entrance cannot be conceived by the drivers, which may lead to higher rate of road traffic crashes.

Distance perception characteristics of drivers in tunnel environment

“…Let us consider two normal populations, X 1 and X 2 , with distributions N 1 (μ 1 , σ 1 2 ) and N 2 (μ 2 , σ 2 2 ), respectively, where μ 1 and μ 2 represent the mean of random variables that follow the two normal distributions, and σ 1 2 and σ 2 2 represent variance of the random variables. Assuming equal variances for both populations, we denote σ 1 2 = σ 2 2 = σ 2 .…”

“…The center point μ 1 of W 1 is shown as Eq. ( 16), and the variance σ 1 2 of W 1 is shown as Eq. ( 17) 16)…”

“…However, the increasing number of tunnel accidents has become a major challenge to the safety of highway operations. Accurate distance perception during vehicle travel is a crucial safeguard for driver safety [1,2]. On open roads, driver distance perception relies heavily on visual cues from the external environment, referred to as visual perceptual cues.…”

Daylighting of road tunnels through external ground-based light-pipes and complex reflective geometry

“…Among these facts, the slow adaptation of humans to weakly lighting conditions (Adrian, 1982;CIE Publ. 88:2004, 2004Mehri et al, 2017Mehri et al, , 2018Mehri et al, , 2019Mehri et al, , 2020 and the black-hole effect in the entrance (Si-qi and Xiao-ming, 2015) together with the flicker effect in the interior and longer tunnels (Iacomussi, Radis & Rossi, 2018;Peña-García, 2018;Du et al, 2020) play a key role.…”

Investigating the General Safety of Playground Equipment and its Compliance With National Standards

“…This issue has caused the risks of moving, running, and walking on the playgrounds' floor. Other factors, including brightness and lighting, may also affect accidents [11].…”