Proposal to establish revised terms of reference for the IWG RD-ASEP covering vehicles of categories M₁, N₁, and L₃. The group shall modify current regulations to mandate revised RD-ASEP, update Annex 9, delete Annex 7 and update relevant paragraphs in the main body and Annex 3 of UN R51, develop limit curves for different riding situations in UN R41-05, consider relevant transitional provisions, and develop coordination between UN R51 and UN R138. The IWG shall be chaired by Germany with OICA as Secretary for M/N categories and IMMA for L category, and shall present a working document for M₁ and N₁ vehicles by February 2028.

Proposal to establish revised terms of reference for IWG RD-ASEP covering vehicles of categories M₁, N₁, and L₃. For M₁ and N₁ vehicles, objectives include modifying current regulations to mandate revised RD-ASEP, updating Annex 9, deleting Annex 7, and developing coordination between UN R51 and UN R138. For L₃ vehicles, objectives include updating RD-ASEP limits. The IWG shall be chaired by Germany with OICA and IMMA as secretaries, shall report to GRBP, and shall present comprehensive proposals for M₁ and N₁ by February 2028.

Proposal to amend Annex 7, paragraph 3.1, to add provisions allowing discard of test runs when additional operating conditions lead to riding conditions not expected to occur in real traffic such as front wheel lift up, apparent wheel spin, chain slap, or engine lugging, and amend paragraph 3.2.2 to specify that if unusual riding conditions occur during testing, the test shall be performed in the next higher gear and maximum vehicle speed shall be reached at line BB’ instead, thereby ensuring consistency with the 05 and 06 series of UN Regulation No. 41.

Two presentations addressed road traffic noise: NEFOM presented findings on the gap between type-approval motorcycle noise levels and real-world noise exposure, noting that roadside measurements show motorcycles can generate noise approaching 100 dB(A) and that 20% of vehicles appeared tampered. A University Medical Center Mainz presentation highlighted scientific evidence that traffic noise contributes to cardiovascular, metabolic, neurological, and sleep-related disorders affecting over 130 million Europeans. Discussion noted the importance of reducing night-time noise exposure and that stricter UN-R41-06 limits cannot yet be heard in the current fleet. The Cross Matrix topic was deferred to the next session.

The 20th session of the Task Force on Vehicle Sound convened on 14 April 2026. The session adopted the draft agenda and reviewed the 19th session report with a minor correction. The cross-matrix, defined in 2021 to assess traffic noise reduction policies through traffic scenarios and models, was rediscussed. A model based on RD-ASEP monitoring data was presented, showing significant deviations from EU-CNOSSOS predictions. Additional data are needed for M₃/N₃ and L-category vehicles. Extension of the cross-matrix to L-categories was proposed, utilising data from UN R41-06 RD-ASEP. A subgroup was established to develop scenarios, particularly for L-categories, and review available models. The next meeting is scheduled for 9 June 2026.

NEFOM and S.O.S. represent over 1 million European citizens experiencing noise from light vehicles inconsistent with Certificate of Conformity figures. The LENS project conducted 2300 measurements of 2300 vehicles, finding measured noise levels in practice much higher than type approval, sometimes reaching 100 dB(A). The A-filter used in Certificates of Conformity is unsuitable for noise levels above 70 dB and does not represent human perception. Sound limits for motorcycles have not changed since 2015 and remain too high. The document requests further improvements to RD-ASEP testing, replacement of the A-filter with a C-filter, and significant reduction of sound level limits for motorcycles.