This report is supplementary to CIE 12.2-1977 Recommendations for the Lighting of Roads for Motorized Traffic. The first part contains a survey of the combined effects of permanent or incidental causes which progressively impair the performance of road lighting installations. The second part points out what preventive measures can be taken in designing and installing a system to reduce or slow down the deterioration of materials (columns, lanterns, light sources, auxiliary gear). The last part indicates preventive maintenance operations aimed at protecting materials against deterioration or at restoring, as much as possible, the initial performance of the installation. The different methods of maintenance and replacement of various items are analyzed.