Design of Solar Optical Fiber Lighting System for Enhanced Lighting in Highway Tunnel Threshold Zone: A Case Study of Huashuyan Tunnel in China

Table 2

The stopping sight distance   for highway tunnel lighting (m).

Design speed (km/h)	Longitudinal slope (°)
	−4	−3	−2	−1	0	1	2	3	4
100	179	173	168	163	158	154	149	145	142
80	112	110	106	103	100	98	95	93	90
60	62	60	58	57	56	55	54	53	52
40	29	28	27	27	26	26	25	25	25