Tunnel illumination is generally divided into five sections, such as close, inlet, transition, intermediate and exit, each of which has different functions:
(1) Close to paragraph: the near section of the tunnel refers to a section of the road near the entrance of the tunnel, close to the beginning of the section of the entrance is a lighting parking distance, lighting parking distance according to the road tunnel lighting design rules value, by the way, close to the field in the tunnel hole, its brightness from outside the natural conditions, no artificial
But because the brightness of the near segment is closely related to the illumination in the cavity, it is also customary to call it a lighting section.
(2) Entrance section: The entrance section is the first illumination section after entering the tunnel, previously referred to as an adaptive segment, this segment requires artificial illumination.
(3) Transition section: The Transition section is a section of illumination between the entrance and the middle segment.
This section is used to solve the problem of driver vision adaptation from the high brightness of the entrance segment to the low luminance of the middle segment.
(4) Intermediate paragraph: Driver after driving through the Entrance section and Transition section, the driver's vision to complete the dark adaptation process, the middle section Lighting task is to ensure the safety and stability in the tunnel.
(5) Export section: In the daytime, so that the driver can gradually comply with the export of strong light, to eliminate the "white hole" phenomenon; at night, the driver can see the outside road in the hole line and obstacles, to eliminate the exit of the "black hole" phenomenon, the common practice is to use street lights as a continuous lighting outside the hole.
In the daytime, the Illumination Hall of the tunnel exit section and the illumination degree of the entrance section should be higher than that of the tunnel. At night, on the contrary, should be lower than the tunnel in the fundamental illumination of the value of the hall, when there is street lighting outside the tunnel, the tunnel brightness value should not be less than twice times the open-air brightness.