16. The expert from Japan proposed clarifications (ECE/TRANS/WP.29/GRBP/2024/20 and GRBP-80-33) which were based on the considerations of the former Task Force on Quiet Road Transport Vehicles (TF QRTV). GRBP adopted the proposal and requested the secretariat to submit them for consideration and vote at the March 2025 sessions of WP.29 and AC.1 as Supplement 1 to the 02 series of amendments to UN Regulation No. 138.

17. The experts from WBU and OICA presented the outcome of their joint events in Aachen (June 2024) and in Neuburg (August 2024), which tested external vehicle sound and assessed situations where electric vehicles equipped with an acoustic vehicle alerting system (AVAS) might be overheard (GRBP-80-32), and replied to clarifying questions.

18. The expert from EC introduced a proposal for a new 03 series of amendments to UN Regulation No. 138 (GRBP-80-06 and GRBP-80-24). According to her, the proposal contained improvement both in terms of safety (mandatory AVAS sound up to 30 km/h, increase in the minimum sound levels at low speed) and in terms of environmental noise (prohibition of AVAS sound above 30 km/h, decrease in the maximum sound levels in standstill, forward and reverse). Finally, she invited GRBP experts to provide feedback in September-October 2024, with the aim to incorporate comments and improvements and to submit a working document to the next session of GRBP.

19. The experts from France, Germany, Japan, Netherlands, United Kingdom, OICA and WBU expressed their interest in participating in further discussions on the topic. Given the proposed significant changes, some experts requested more time to study the proposal. The expert from Japan sought scientific evidence for the proposal. The expert from Italy pointed out the need of a cost/benefit analysis of environmental aspects.

20. The expert of OICA introduced draft amendments to the 02 series of amendments to UN Regulation No. 138 (GRBP-80-28), which took into account a new definition of “Exterior Sound Enhancement System” (ESES) proposed for UN Regulation No. 51 in ECE/TRANS/WP.29/GRBP/2024/22 submitted by OICA. According to OICA, UN Regulation No. 138 should remain a safety UN Regulation while the environmental concerns should be addressed by UN Regulation No. 51. GRBP noted that the two Regulations provide parallel specifications for an overlapping speed range (20 – 50 km/h).

21. Given the complexity of the problem and lack of time, GRBP was not in a position to take a decision on the proposals by the experts of EC and OICA. To make progress, the Chair suggested that the proposals be first considered within a new group of interest before GRBP would revert to them at the next session. GRBP agreed that discussions could first start in October 2024 in the framework of the new subgroup on UN Regulation No. 51 (see para. 14 above) with a later establishment of a separate subgroup on UN Regulation No. 138, if necessary.

22. The expert from EC proposed to delete a footnote in UN Regulation No. 138 stating that, at this stage, only acoustic measures should be developed in order to overcome the concern of reduced audible signals from electrified vehicles and that alternative, non-acoustic measures, should only be developed later by the respective Working Parties (GRs) (GRBP-80-13). According to her, other GRs should be requested to develop such alternative measures as soon as possible, given the serious public health concerns due to vehicle noise. The Chair replied that he would convey this request to WP.29 and that, for the time being, deleting of the footnote seemed to be premature.