In the tunnel light design scheme, tunnel light is divided into three categories according to their functions: lifting lighting fixtures, basic lighting fixtures and emergency lighting fixtures. The light distribution design schemes of these three types of tunnel lights are different. At this stage, the common light distribution methods of tunnel lights include condenser type light distribution, side shot type light distribution, Lambertian type light distribution and spider wing type light distribution.

The tunnel light chromaticity requirements for the tunnel passage section and the entrance section are relatively high, and the road between the lights is small, and some are only 1~1m. When designing the light distribution of tunnel luminaires, what must be considered is how to improve the chromaticity of the ground. In addition, the chromaticity and uniformity inside the tunnel must also be considered. Therefore, to enhance the chromaticity of the tunnel lamp, the bat-wing type light distribution or the Lambertian type light distribution should not be used, but the concentrating type light distribution or the side-emitting type light distribution should be selected.

In the middle section of the long tunnel, the tunnel light interval is relatively large, 4~6m. When designing the light distribution of tunnel lamps, what must be considered is the chromaticity and uniformity in the tunnel. Therefore, the light distribution of the tunnel lamp in the middle section can not be a positive or side-fired light distribution, but a bat-wing type light distribution should be used. Or Lambertian light distribution. For tunnels longer than 100m in length, an emergency tunnel lighting system must be set, and the lighting termination time shall not exceed 0.3 seconds, the holding time shall not be less than 3 minutes, and the emergency lighting shall be activated. The chromaticity of the ground in the tunnel shall not be lower than the median chromaticity. Therefore, the emergency tunnel light is arranged at a large interval of 8~10 meters, and the emergency tunnel light distribution design should be a bat-wing shape.