Proposal to combine the provisions of individual UN Regulations Nos. 4, 6, 7, 23, 38, 50, 77, 87 and 91 into a single UN Regulation on uniform provisions concerning approval of light-signalling devices for power-driven vehicles and their trailers. This consolidation simplifies and streamlines requirements without changing detailed technical specifications already in force. The Regulation applies to eleven categories of lamps including rear-registration plate illuminating, direction indicator, position, stop, end-outline marker, reversing, manoeuvring, rear fog, parking, daytime running, and side marker lamps. Requirements address administrative provisions, type approval, approval marks using unique identifiers or conventional E-marks, general and specific technical requirements for each lamp function, photometric and colorimetric characteristics, etc.