1. Proposal to amend the 04 and 05 series of UN R41 and the 02 series of UN R63 to allow use of the latest state of the art ISO 10844 test track.
2. ISO has updated the ISO 10844 standard to reduce track-to-track variability caused by differing interpretations and implementations of the technical requirements. The tyre/road contribution to the overall sound performance of a motorcycle is lower compared to cars.
3. The improvements from the ISO 10844:2014 to the 2021 version would not result in a need for updating the surface for L-category test tracks: Updating the ISO 10844 reference would have negligible impact on the measurement procedure and measurement results.
4. If however the ISO reference in the L-category noise regulations would be updated without maintaining the current ISO 10844:2014 as an option, IMMA sees a potential risk of tracks needing recertification, creating administrative burden with no practical benefit.
5. If later on, the tracks would need re-surfacing anyway (e.g. due to wear), then these can be built and certified according to ISO10844:2021. Because of the above, IMMA would like to allow certification with the tracks complying to either ISO10844:2014 or ISO10844:2021.
6. This proposal takes the opportunity to introduce proposals for additional corrections in R41/04 and R41/05 as specified below:
   • Supplement 9 to the 04 series of amendments to UN Regulation 41 introduced a new paragraph 12.4, needing to renumber the (former) paragraphs 12.4 to 12.9 (WP.29/2021/4). Due to this renumbering, the reference to paragraph 12.7 in Annex 6 footnote a, and Annex 7 paragraph 2.6 is no longer correct and should be replaced by a reference to paragraph 12.8.
   • With the introduction of the 05 series of amendments the Transitional Provisions were rewritten and footnote a of Annex 6 became obsolete.

Proposal to complete the additional sound emission provisions’ table of the communication form in the 05 series of amendments to UN R41 to avoid oversight in data collection and entries.