1. The Working Party on Noise and Tyres (GRBP) held its seventy-ninth session from 6 to 9 February 2024 in Geneva. The meeting was chaired by Mr. S. Ficheux (France). Experts from the following countries participated in the work following Rule 1(a) of the Rules of Procedure of the World Forum for Harmonization of Vehicle Regulations (WP.29) (TRANS/WP.29/690/Rev.2): Canada, China, Czechia, Finland, France, Germany, India, Italy, Japan, Netherlands, Norway, Republic of Korea, Russian Federation, Spain, Sweden, Switzerland and United Kingdom of Great Britain and Northern Ireland. Experts from the European Commission participated. Experts from the following non-governmental organizations also participated: American Automotive Policy Council (AAPC), Bureau International Permanent des Associations de Vendeurs et Rechapeurs de pneumatiques (BIPAVER), European Tyre and Rim Technical Organization (ETRTO), Imported Tyre Manufacturers Association (ITMA), International Motorcycle Manufacturers Association (IMMA), International Organization for Standardization (ISO), International Organization of Motor Vehicle Manufacturers (OICA), Pew Environment Group and World Blind Union (WBU).

2. GRBP considered and adopted the agenda (ECE/TRANS/WP.29/GRBP/2024/1, as amended by GRBP-79-01). GRBP noted the running order proposed by the Chair (GRBP-79-18-Rev.1). The informal documents are listed in annex I of the session report. The GRBP informal groups are given in annex III.

GRBP-79-01 | GRBP: Updated agenda for the 79th (February 2024) session

GRBP-79-18/Rev.1 | GRBP: Running order of the agenda for the 79th (February 2024) session

GRBP/2024/1 | GRBP: Annotated provisional agenda for the 79th (February 2024) session

3. Recalling its previous discussion on ECE/TRANS/WP.29/GRBP/2023/14 and ECE/TRANS/WP.29/GRBP/2023/15, GRBP considered revised proposals for the use of the latest standard ISO 10844:2021 test track which had been submitted by the experts from France, IMMA and ISO (GRBP-79-13 and GRBP-79-14). GRBP adopted the proposals, as laid down in GRBP-79-13 and GRBP-79-14, and requested the secretariat to submit them for consideration and vote at the June 2024 sessions of WP.29 and the Administrative Committee (AC.1) as draft Supplement 3 to the 05 series of amendments and draft Supplement 11 to the 04 series of amendments to UN Regulation No. 41.

GRBP-79-13 | UN R41: Proposal to replace ECE/TRANS/WP.29/GRBP/2023/15 Replace the proposal for Supplement 3 of the 05 Series of amendments

GRBP-79-14 | UN R41: Proposal to replace ECE/TRANS/WP.29/GRBP/2023/14 Proposal to replace the Supplement 11 of the 04 Series of amendments

4. The expert from IMMA presented interpretation documents GRBP-79-15, GRBP-79-16 and GRBP-79-38 on the application of the Real Driving Additional Sound Emission Provisions (RD-ASEP) in the 05 series of amendments to UN Regulation No. 41. He explained that the objective of his documents was to avoid an excessive number of test runs through the proposed interpretation of the number of test points and the applicable test speed. Following a brief exchange of views, GRBP invited its experts to send their comments to IMMA and decided to revert to this topic at the next session.

GRBP-79-15 | UN R41: Interpretation document with regards to the number of test points when performing test runs for type approval

GRBP-79-16 | UN R41: Interpretation document with regards applicable test speed of the motorcycle when performing test runs for type approval

GRBP-79-38 | UN R41: Introduction to the proposed interpretation documents

5. The expert from the Informal Working Group on Measurement Uncertainties (IWG MU) presented their final report (GRBP-79-02) and a draft document for reference (ECE/TRANS/WP.29/GRBP/2024/8 and GRBP-79-48-Rev.1). During an in-depth discussion, several experts from contracting parties expressed concerns about the formal adoption of the document for reference and its legal status. They pointed out that the document could be misinterpreted as being legally binding and modifying the established sound limits in UN Regulation No. 51. In the absence of consensus, GRBP postponed the discussion to the next session.

GRBP-79-02 | Noise measurement uncertainties status report to GRBP

GRBP-79-48/Rev.1 | Noise Measurement Uncertainties: Proposal to amend GRBP/2024/8

GRBP/2024/8 | Measurement uncertainties when testing in UN Regulations under the purview of GRBP Proposal from the Measurement Uncertainties informal group for a Document for Reference providing a general approach on how to handle measurement uncertainties in UN Regulations (initially addressing UN Regulations Nos. 51 and 117).

6. GRBP took note of the status report of IWG RD-ASEP (GRBP-79-11).

GRBP-79-11 | IWG ASEP: Status report

7. The expert from OICA presented a proposal with corrections and clarifications on the power definition, calibration, temperature correction and reference sound assessment (GRBP-79-33-Rev.1). Subject to deletion of the second occurrence of double paragraph 2.8., GRBP adopted the proposal and requested the secretariat to submit it for consideration and vote at the June 2024 sessions of WP.29 and AC.1 as draft Supplement 10 to the 03 series of amendments to UN Regulation No. 51.

GRBP-79-33/Rev.1 | UN R51: Proposal for a supplement 10 to the 03 series of amendments Some corrections and clarifications concerning power definition, calibration, temperature correction and Reference sound assessment

8. The expert from OICA proposed to extend the ASEP provisions from annex 7 of the 03 series of amendments to UN Regulation No. 51 to electric vehicles (GRBP-79-43). GRBP invited its experts to provide comments to OICA, with the aim of continuing discussion at the next session, based on an official document.

GRBP-79-43 | UN R51: Proposal for a supplement 11 to the 03 series of amendments In introducing ASEP in Annex 7 in 2016, the scope was limited to vehicles with internal combustion engines (ICE) based on the experience of variabilities in the exhaust silencing systems. Electric driven vehicles have been exempted from ASEP. For electric driven vehicles the new UN Regulation No. 138, dealing with the reduced audibility of these vehicles, was worked out until 2017. At that moment no one expected sound enhancement systems beyond the scope and aim of UN R138. This proposal is an approach to address the concern that electric vehicles might be equipped with sound enhancement systems beyond the scope and aim of UN R138. This proposal does not require any changes to UN R138.01. This proposal is given as a supplement to enable the quickest entry into force, providing all manufacturers clear direction on the design of sound enhancement systems.

9. The expert from OICA presented an interim report on the ongoing ASEP/ RD-ASEP study (GRBP-79-45) which included a first set of data on RD-ASEP monitoring according to the 03 series of amendments to UN Regulation No. 51. GRBP noted the low response rate and encouraged all type approval authorities and technical services of contracting parties applying UN Regulation No. 51 to transmit the relevant data, as a sufficient number of datasets are needed to conduct a good study. In reply to a question from the expert of EC, the expert of OICA indicated that they would need around 1,000 data sets to conduct a good study on RD-ASEP. The expert from OICA also clarified that only an excel data sheet should be transmitted, without a pdf report.

GRBP-79-45 | ASEP / RD-ASEP Study