After having reviewed and defined the various factors to be taken into consideration with regard to the lighting of tunnels and road underpasses, the present document sets out recommendations concerning the daytime and night-time lighting. It also describes the measures to be taken into consideration in order to adapt this lighting to the fluctuations in the external lighting or in the case of failure of the normal electrical power supply of the lighting installations. Attention is also given to maintenance which has to be carried out in order to ensure the lasting quality of the installations. It is also important to note that while this publication is part of a general activity aimed at improving road safety, safety depends on a large number of factors among which lighting is only one particular constituent. The contribution of lighting in this context is to enable the road user to perform his visual tasks by ensuring a sufficient visibility of objects.