A tunnel is an enclosed passage which restricts the normal daytime illumination of the roadway and produces a shadow that limits the ability of the driver to see objects or obstructions within the structure. Tunnel lighting is provided to illuminate the presence and movement of other road users or objects. It helps define the tunnel’s geometry such that a motorist is encouraged to maintain speed and able to safely navigate through the tunnel. The more heavily the world is populated, the more tunnels are needed to free up valuable ground areas or to cross mountain ranges and bodies of water, and the more important tunnel lighting becomes.
Due to the complex and highly specialized needs of the application, tunnel lighting is challenged to facilitate the flow of vehicular and/or pedestrian traffic efficiently and effectively. It must address a diversity of concerns, including traffic density and speed, luminance contrast, eye adaptation, flicker effects, glare, and the luminaire performance and reliability under heavy duty use and harsh environmental conditions. The category of tunnel lighting products also includes those used for illuminating underpasses. An underpass is defined as a covered or underground passage of which the length and physical configuration do not substantially reduce a driver’s ability to see objects ahead.
at the Open Lighting Product Directory (OLPD)
