Tunnel lighting is one of the most difficult part of the artificial lighting and at the same time it is very heavily bound with different normatives. The fundamental visual problem in tunnels is what we call "the black hole effect" which prevents drivers from seeing the interior of the tunnel during the day, when they are at a certain distance from its mouth and eventual obstacles are not visible. The sole purpose of the tunnel lighting is to provide secure drive through all the tunnel zones; the access zone, transition zone and the exit zone during night and day. The main photometric characteristics necessary to establish lighting quality for a tunnel are the ones: luminance level of the roadway, luminance level of the walls (especially up to a height of 2m), luminance distribution uniformity in roadway and walls, limitation of glare, control of Flicker's effect.
The requirements for the lighting systems used for railways are also very specific. The luminaires must for example fulfill the parametrs of being in electric class II, shock resistant, anti-vandal made. Therefore the Czech Railways has formed their own certification process (norm) of the luminaires approval, according to which the individual luminaires are judged and either approved, or denied for the railway use. The railway lighting covers not only lighting the railway stations and platforms for the public transport, however also the freight stations.
The speciality of railways lighting also lies in placing the luminaires directly to traction poles for direct rail yard illumination.
