Road tunnels represent an environment of particular interest for those who design and build artificial lighting systems. Here, in fact, there are unique conditions of brightness variations which, more than elsewhere, pose problems of energy efficiency, maintenance and specific safety measures.
In response to the energy issue, in recent years there has been a widespread diffusion of LED technology for projectors, with considerable savings in terms of energy costs and, consequently, of polluting emissions.
To guarantee safety, the legislation in Italy defines the tunnel as a dangerous environment and, through the UNI 11095 standard,
specifies the lighting requirements of the lighting system of a road tunnel, in order to ensure that the driver of a vehicle, both day and night, can enter, cross and exit the covered section at a speed at least equal to local speed limit, with a degree of safety no lower than that present on the sections of road to which the tunnel is a part, in adequate conditions of visual comfort.