Research Article
Design of Counter Beam Tunnel Lights for CIE 88 : 2004 Regulation in Threshold Zone
Figure 3
The black line is the luminance reduction curve for CIE 88 : 2004 standard. The length of threshold zone = 0.5 SD, where Lth is 100 %. Threshold zone length = stopping distance (SD). The red lines indicate the target luminance in the zones of tunnels.