In the majority of tunnels the natural penetration of light does not allow satisfactory conditions of visibility for the users. It is therefore necessary to install artificial lighting offering satisfactory conditions of visibility and comfort to the users.
In terms of functionalities, the lighting installation must allow for:
A lighting installation should be designed respecting several criteria, notably those relating to:
Several types of installations are possible; the most common are symmetrical lighting and counter-flow lighting. Depending on the characteristics of the tunnel and the objectives defined, the lighting fittings may be installed in one or more lines, above the road, on top of walls of the tunnel...