Proposal to clarify the definitions and requirements associated with the installation of “single lamps”, “lamps marked D” and “Interdependent lamps” and to ensure that the introduction of the new class F marking materials does not conflict with the mandatory requirements for existing class C materials. This proposal also would extend modifications that introduced provisions for interdependent direction indicator lamps in the 06 series of amendments to UN R48 to the 04 and 05 series in order to avoid an unjustified design restriction for approvals under the earlier versions of the regulation.