Covers filament lamps to be used in headlamps, fog-lamps and signalling lamps for road vehicles and specifies the technical requirements with methods of test and basic interchangeability (dimensional, electrical anad luminous). It applies to those filament lamps which may be the subject of legislation. In particular, it covers those filament lamps contained in Regulation No. 37 of the Geneva agreement of 20 March 1958 of the United Nations Economic Commission for Europe (ECE) concerning the adoption of uniform conditions of approval and reciprocal recognition of approval for motor vehicle equipment and parts.