Scaled hillsides to decrease the energy consumption of lighting installations in road tunnels

Abstract

The reduction of energy demands of the lighting installations in road tunnels, has become a matter of active research in the last years. Among the different strategies, the decrease of reflectance in the surroundings of portal gate, has been pursued by means of forestation or installation of elements with lower reflectance than concrete. However, these strategies are difficult to carry out due to remarkable problems like initial implementation, maintenance, shape of the mountain and other properties of the terrain. Furthermore, they consider only the decrease in the reflectance without controlling the directions where the light is reflected. This work proposes the introduction in the hillside around the portal of discrete surfaces with given orientation to deviate the reflected light from the visual field of drivers. The target is to ease the visual adaptation, making the visual transition smoother, and decrease the glare and luminance in the zone of the road that determines the lighting requirements inside the tunnel. The result is a scaled-like zone around the portal whose parameters are calculated, analyzed, and presented in this work.