TUNNEL INTERIOR LIGHTING FOR SAFETY IN TWO-WAY TRAFFIC

Abstract

This paper proposes a tunnel interior lighting system for safety in two-way traffic on highways. The target tunnel had longitudinal slopes with sag (vertical curve) of 4% at the maximum, which had been the concern leading to a rear-end collision in speed degradation of a preceding car and a serious front collision in the two-way traffic. Since 2010 in Japan, many tunnel lighting systems had been replaced by LED luminaires, which in some cases resulted in uneven luminance distribution of the road surface and discomfort glare even in the tunnels considered the CIE recommended criteria including uniformity of road surface luminance and a glare restriction (CIE 2004). Considering these condition, therefore we reviewed lighting system requirements in the tunnel with two-way traffic.