Study of road tunnel threshold zone lighting reduction coefficient

Abstract

The luminance in the road tunnel threshold zone attracts broad attention due to its enormous energy consumption and direct influence on tunnel transportation security. Current lighting design methods in threshold zones mostly adopt the reduction coefficient method. However, the determination of reduction coefficient k simply considers tunnel design speed and flow rate, while excluding outside tunnel luminance and threshold zone color temperature and luminance, which have a major impact on driver visual adaptation. Existing problems in the determination of k value are analyzed; a visual performance experiment is utilized; and the reaction time of drivers in changeable outside tunnel luminance and threshold zone color temperature and luminance conditions is obtained; thus, the equations concerning reduction coefficient variation law are derived. In the end, a comparative analysis is made of the k values of the reduction coefficient stipulated by various norms under different color temperature conditions.