Eye Adaptation Effect Based Study on Configuration of Tunnel Entrance Structure

Due to the unique nature of the tunnel as a tubular structure, an approaching motorist experiences an abrupt change in brightness under the black-hole effect. This sharp change in brightness makes the threshold zone prone to traffic accidents. It is therefore necessary to provide a dimming structure in the threshold zone to support the eye adaptation of the motorist to lower lighting levels in the interior of the tunnel. There is currently a lack of research worldwide on specific configuration parameters and types of dimming structure. This paper covers analysis of the entrance structure of a tunnel and comparison of different alternatives in non-sun-tight louver, its height and transmittance, and proposes an optimal scheme to increase traffic safety and comfort.