Proposal to add a new paragraph 3.6.2.4. to UN R99 in order to clarify how the run-up of dual-level high-intensity discharge (HID) light sources, as e.g. D9S, should be tested during type approval. In addition, the proposal renumbers the part of 3.6.2.2. that applies to gas-discharge light sources containing black stripes as 3.6.2.3. to make the distinction with gas-discharge light sources not containing black stripes.