The IWG RD-ASEP Informal Group is developing a mandatory test procedure for UN R51 to assess vehicle noise emission compliance under conditions other than Annex 3, ensuring no defeat device schemes exist. The Editing Task Force created a consolidated R51.04 draft incorporating Supplements up to Supplement 11, with mandatory random RD-ASEP testing for approval and revised control ranges. R51.04 RD-ASEP expands vehicle speed range to 1-100 km/h, adds vehicle performance criteria, implements random test points, and requires testing for approval. Working document submission is expected September 2027, with expected adoption February 2028.