“…According to the International Commission on Illumination (CIE), L th should be designed based on three references, i.e., the highest L 20 (likely to occur during at least 75 daytime hours per year), the maximum traffic flow, and the maximum vehicle speed [ 4 ]. However, the actual L 20 , traffic flow, and vehicle speed, are often much smaller than the above references [ 5 , 6 , 7 , 8 ]. Therefore, if the threshold zone luminance always adopts the designed value, it will lead to the fact that the lighting luminance is much higher than the real demand during the 95% of the daytime [ 9 ], thus resulting in over-illumination [ 10 ].…”