5. The experts of IWG MU introduced a new draft document for reference on measurement uncertainties which addressed UN Regulations Nos. 51 and 117 as a first step (GRBP-78-07). The experts from France and the United Kingdom posed questions, while the experts from Germany and the Netherlands pointed out a large test track uncertainty. The Chair invited IWG MU to liaise with the above experts with the aim to prepare a revised document for the next session.

12. The expert of the Task Force on Quiet Road Transport Vehicles (TF QRTV) presented their proposals for a new series of amendments to UN Regulation No. 138 (ECE/TRANS/WP.29/GRBP/2024/2, GRBP-79-34-Rev.1). The expert from ISO tabled further clarifications based on the final draft international standard ISO 16254 (GRBP-79-30). The expert from Australia withdrew their comments in GRBP-79-41.

13. Some experts from contracting parties supported the proposals as striking a delicate balance between road safety and environmental noise, while some others expressed their wish to postpone a decision on the proposals to the September 2024 session of GRBP. The expert of EC expressed that, albeit less ambitious than the European Union policy on noise reduction would prescribe, they could still support this proposal while at the same time work on further improvements for the next GRBP session.

14. The representative of WBU welcomed the mandatory acoustic vehicle alert system (AVAS) sound in reverse driving as contributing to the safety of blind people. He also appreciated optional AVAS sound at stationary as well as above the mandatory AVAS speed range of 0 to 20 km/h.

15. The expert from OICA raised concerns over the proposals (GRBP-79-44), in particular, the definition of “natural sound” as not being technologically neutral, and the sound limit in the speed range between 20 and 50 km/h.

16. As a compromise, the Chair of TF QRTV submitted an updated version (GRBP-79-34-Rev.2). Following an in-depth discussion, GRBP adopted the revised proposals, as amended by GRBP-79-34-Rev.2 and requested the secretariat to submit them for consideration and vote at the June 2024 sessions of WP.29 and AC.1 as the draft 02 series of amendments to UN Regulation No. 138. The expert of EC pointed out that the new version went further towards disconnecting AVAS from safety issues, and clearly stated concern on this new proposal.