30. Based on GRBP-73-28-Rev.1, GRBP adopted a list of main decisions (Annex IV of the session report) in accordance with silence procedure.

28. The expert from France presented an updated schedule of meetings that were of interest to GRBP experts (GRBP-71-13-Rev.5).

2. GRBP considered and adopted the agenda (ECE/TRANS/WP.29/GRBP/2021/1, as amended by GRBP-73-01). GRBP noted the running order proposed by the Chair (GRBP-73-06). The list of informal documents is contained in Annex I to the session report. The list of GRBP informal groups is reproduced in Annex V.

19. GRBP took note of the activities of the Task Force on Tyre Pressure Monitoring System and on Tyre Installation (TF TPMSTI) (GRBP-73-13) and addressed amendment proposals on the requirements for the communication interface between the towing and towed vehicles that had been prepared by TF TPMSTI (ECE/TRANS/WP.29/GRBP/2021/6 and GRBP-73-03).

20. GRBP adopted the proposals and requested the secretariat to include them in a revised document ECE/TRANS/WP.29/2021/10/Rev.1 for consideration and vote at the March 2021 sessions of WP.29 and AC.1 as part of a draft new 01 series of amendments to UN Regulation No. 141.

48. The GRBP Chair reported on the results achieved by GRBP at its seventy-third session (for details, see the report of the session ECE/TRANS/WP.29/GRBP/71).

49. He mentioned that GRBP had adopted modifications to the draft 01 series of amendments to UN Regulation No. 141 (Tyre pressure monitoring system). He recalled that the draft 01 series of amendments would still be addressed by WP.29 this week (ECE/TRANS/WP.29/2021/10) and encouraged the World Forum to consider instead a revised consolidated proposal ECE/TRANS/WP.29/2021/10/Rev.1 under agenda item 4.6.9.

50. He also pointed out that GRBP had agreed to update the Terms of Reference of its two IWGs on Measurement Uncertainties (MU) and on Wet Grip Performance for Tyres in a Worn State (WGWT). WP.29 noted that the revised Terms of Reference were annexed to the report of GRBP at its seventy-third session.

51. WP.29 endorsed the updates of the Terms of Reference of the IWG MU and IWG WGWT.

78. The World Forum considered draft amendments under agenda items 4.6.1 to 4.6.7. and recommended their submission to AC.1 for voting, subject to the following corrections of ECE/TRANS/WP.29/2021/8 under agenda item 4.6.6 (WP.29-183-06):
In paragraph 4.4.1., replace “markings” with “approval mark”.
In paragraph 9.1., delete from the proposal (i.e. keep the paragraph in its current form).

79. The Chair of GRBP presented draft amendment proposals contained in documents ECE/TRANS/WP.29/2021/3, ECE/TRANS/WP.29/2021/10 and Rev.1, ECE/TRANS/WP.29/2021/11 under agenda item 4.6.8 to 4.6.10., to amend UN Regulations Nos. 41, 141 and 142. The World Forum recommended their submission to AC.1 for voting.

3. The expert from IMMA proposed to correct references in the recent series of amendments (GRBP-73-04). GRBP adopted the proposal and requested the secretariat to submit it for consideration and vote at the June 2021 sessions of WP.29 and AC.1 as a draft Supplement to the 04 and 05 series of amendments to UN Regulation No. 41.

6. On behalf of the Informal Working Group on Additional Sound Emission Provisions (IWG ASEP), the expert from Germany introduced a draft new 04 series of amendments to UN Regulation No. 51 (GRBP-73-05). GRBP noted that a revised proposal would be submitted to the next session.

2. GRBP considered and adopted the agenda (ECE/TRANS/WP.29/GRBP/2021/1, as amended by GRBP-73-01). GRBP noted the running order proposed by the Chair (GRBP-73-06). The list of informal documents is contained in Annex I to the session report. The list of GRBP informal groups is reproduced in Annex V.

21. The expert from Finland reported on the progress of the Task Force on Studded Tyres (TF ST) (GRBP-73-07) and introduced a proposal for a new UN Regulation which had been prepared by TF ST (ECE/TRANS/WP.29/GRBP/2021/5). GRBP agreed to revert to the document at the next session, thus giving GRBP experts an opportunity to further study the document and to provide comments.

16. The expert from EC proposed to include C2 and C3 tyres in the Terms of Reference of IWG WGWT (GRBP-73-02). The expert from ETRTO presented a preliminary assessment of wet grip on worn C2 and C3 tyres (GRBP-73-22) and suggested further modifications to the Terms of Reference (GRBP-73-08). Based on a consolidated proposal in GRBP-73-27-Rev.1, GRBP adopted revised Terms of Reference of IWG WGWT as laid down in Annex III to the session report.

29. GRBP noted a mistake in the French text of UN Regulation No. 75 (GRBP-73-09) and requested the secretariat to liaise with the UN services to have it corrected.

26. GRBP took note of the highlights of the November 2020 session of WP.29 on GRBP and common issues (GRBP-73-10). In particular, GRBP was informed that WP.29 had revised a transitional provision on the possibility of granting type approvals according to the preceding series of amendments to a UN Regulation (WP.29-182-11).

5. The experts from EC, ETRTO and OICA reported on their studies on sound level limits (GRBP-73-23, GRBP-73-11 and GRBP-73-25, respectively). To coordinate such initiatives, GRBP decided to establish a taskforce (TF) and sought a volunteer among the experts from Contracting Parties to take the leadership of TF, while OICA agreed to act as secretary. GRBP considered that TF should address the sound level limits of UN Regulation No. 51 and, at a later stage, No. 41. To kick-off the TF activities without delay, the Chair pointed out that he could take the lead of TF on a temporary basis, if needed.

22. On behalf of the Task Force on Reverse Warning (TF RW), the expert from Japan reported on the progress of TF RW (GRBP-73-12). GRBP noted that a proposal for a new draft UN Regulation on reversing alarm would be submitted to the next session. Meanwhile, GRBP encouraged all experts to consider GRBP-73-12 and to provide comments to TF RW, in particular on the proposed sound level limits.

19. GRBP took note of the activities of the Task Force on Tyre Pressure Monitoring System and on Tyre Installation (TF TPMSTI) (GRBP-73-13) and addressed amendment proposals on the requirements for the communication interface between the towing and towed vehicles that had been prepared by TF TPMSTI (ECE/TRANS/WP.29/GRBP/2021/6 and GRBP-73-03).

20. GRBP adopted the proposals and requested the secretariat to include them in a revised document ECE/TRANS/WP.29/2021/10/Rev.1 for consideration and vote at the March 2021 sessions of WP.29 and AC.1 as part of a draft new 01 series of amendments to UN Regulation No. 141.

7. The expert from Norway, in his capacity of Chair of the Informal Working Group on Measurement Uncertainties (IWG MU), reported on the progress of IWG MU (GRBP-73-14-Rev.1) and proposed to update its Terms of Reference (GRBP-73-16). GRBP adopted the revised Terms of Reference, as laid down in Annex II of the session report.

8. The experts from IWG MU also presented a draft reference document with a general approach to estimate measurement uncertainties (GRBP-73-15) and draft amendments to the 03 series of amendments to UN Regulation No. 51 (GRBP-73-17).

7. The expert from Norway, in his capacity of Chair of the Informal Working Group on Measurement Uncertainties (IWG MU), reported on the progress of IWG MU (GRBP-73-14-Rev.1) and proposed to update its Terms of Reference (GRBP-73-16). GRBP adopted the revised Terms of Reference, as laid down in Annex II of the session report.

4. The expert from Norway, in his capacity of Chair of the Informal Working Group on Measurement Uncertainties (IWG MU), reported on the progress of IWG MU (GRBP-74-20) and proposed to update its Terms of Reference (GRBP-74-12). GRBP adopted the revised Terms of Reference, as laid down in Annex II.

8. The experts from IWG MU also presented a draft reference document with a general approach to estimate measurement uncertainties (GRBP-73-15) and draft amendments to the 03 series of amendments to UN Regulation No. 51 (GRBP-73-17).

15. On behalf of IWG for Wet Grip on Worn Tyres (WGWT), the expert of France reported on their progress (GRBP-73-18).

17. The expert from ETRTO proposed to introduce in UN Regulation No.117 a definition of “ice tyre” for C1 tyres (GRBP-73-19). The Chair invited ETRTO to submit a working document for consideration at the next session.

11. The expert from France proposed a new definition for the radial structure (GRBP-73-20-Rev.1). The expert from ETRTO made a study reservation. GRBP invited the expert from France to prepare, in cooperation with ETRTO, a new working document for the next session.

14. The expert from France proposed to update and revise the text of UN Regulation No. 109 (GRBP-73-21). The experts from the Netherlands and BIPAVER commented on the proposal. GRBP invited the experts from France, Netherlands and BIPAVER to cooperate with the aim to prepare a working document for the next session.

18. The experts from France, the Netherlands and BIPAVER proposed to align the provisions for retreaded tyres with the previously adopted proposals for UN Regulations Nos. 54 and 117 and to cover all tread materials (ECE/TRANS/WP.29/GRBP/2021/16). The expert from ETRTO commented on the proposal and suggested further modifications (GRBP-74-29-Rev.1 and GRBP-74-30-Rev.2). GRBP adopted the proposal with the amendments in Annex IV and requested the secretariat to submit it for consideration and vote at the March 2022 sessions of WP.29 and AC.1 as draft Supplement 11 to UN Regulation No. 109.

16. The expert from EC proposed to include C2 and C3 tyres in the Terms of Reference of IWG WGWT (GRBP-73-02). The expert from ETRTO presented a preliminary assessment of wet grip on worn C2 and C3 tyres (GRBP-73-22) and suggested further modifications to the Terms of Reference (GRBP-73-08). Based on a consolidated proposal in GRBP-73-27-Rev.1, GRBP adopted revised Terms of Reference of IWG WGWT as laid down in Annex III to the session report.

5. The experts from EC, ETRTO and OICA reported on their studies on sound level limits (GRBP-73-23, GRBP-73-11 and GRBP-73-25, respectively). To coordinate such initiatives, GRBP decided to establish a taskforce (TF) and sought a volunteer among the experts from Contracting Parties to take the leadership of TF, while OICA agreed to act as secretary. GRBP considered that TF should address the sound level limits of UN Regulation No. 51 and, at a later stage, No. 41. To kick-off the TF activities without delay, the Chair pointed out that he could take the lead of TF on a temporary basis, if needed.

23. GRBP recalled the studies which were introduced under agenda items 2 and 3.

27. GRBP noted a revised list of the GRBP priorities (GRBP-73-24) and that the Chair would convene in February 2021 an informal meeting on this issue as well as on the leadership of TF on noise limits.

5. The experts from EC, ETRTO and OICA reported on their studies on sound level limits (GRBP-73-23, GRBP-73-11 and GRBP-73-25, respectively). To coordinate such initiatives, GRBP decided to establish a taskforce (TF) and sought a volunteer among the experts from Contracting Parties to take the leadership of TF, while OICA agreed to act as secretary. GRBP considered that TF should address the sound level limits of UN Regulation No. 51 and, at a later stage, No. 41. To kick-off the TF activities without delay, the Chair pointed out that he could take the lead of TF on a temporary basis, if needed.

4. The expert from EC briefed GRBP on an ongoing study of the impact assessment of Euro 5 sound emissions level limits for L-category vehicles (GRBP-73-26). Several experts invited him to keep GRBP informed of the study progress.

23. GRBP recalled the studies which were introduced under agenda items 2 and 3.

16. The expert from EC proposed to include C2 and C3 tyres in the Terms of Reference of IWG WGWT (GRBP-73-02). The expert from ETRTO presented a preliminary assessment of wet grip on worn C2 and C3 tyres (GRBP-73-22) and suggested further modifications to the Terms of Reference (GRBP-73-08). Based on a consolidated proposal in GRBP-73-27-Rev.1, GRBP adopted revised Terms of Reference of IWG WGWT as laid down in Annex III to the session report.

2. GRBP considered and adopted the agenda (ECE/TRANS/WP.29/GRBP/2021/1, as amended by GRBP-73-01). GRBP noted the running order proposed by the Chair (GRBP-73-06). The list of informal documents is contained in Annex I to the session report. The list of GRBP informal groups is reproduced in Annex V.

12. GRBP noted that the experts of BIPAVER had withdrawn document ECE/TRANS/WP.29/GRBP/2021/2.

13. GRBP noted that the experts of BIPAVER had withdrawn ECE/TRANS/WP.29/GRBP/2021/3.

10. The expert from ETRTO introduced ECE/TRANS/WP.29/GRBP/2021/4. GRBP adopted the proposal and requested the secretariat to submit it for consideration and vote at the June 2021 sessions of WP.29 and AC.1 as a draft Supplement to the 02 series of amendments to UN Regulation No. 30.

21. The expert from Finland reported on the progress of the Task Force on Studded Tyres (TF ST) (GRBP-73-07) and introduced a proposal for a new UN Regulation which had been prepared by TF ST (ECE/TRANS/WP.29/GRBP/2021/5). GRBP agreed to revert to the document at the next session, thus giving GRBP experts an opportunity to further study the document and to provide comments.

30. The expert from Finland presented a revised proposal for a new UN Regulation on studded tyres that had been prepared by TF ST (ECE/TRANS/WP.29/GRBP/2021/5/Rev.1). The expert from ETRTO suggested several modifications to the proposal (GRBP-74-32). GRBP adopted ECE/TRANS/WP.29/GRBP/2021/5/Rev.1 as amended by GRBP-74-32 and requested the secretariat to submit it for consideration and vote at the March 2022 sessions of WP.29 and AC.1 as a new draft UN Regulation.

19. GRBP took note of the activities of the Task Force on Tyre Pressure Monitoring System and on Tyre Installation (TF TPMSTI) (GRBP-73-13) and addressed amendment proposals on the requirements for the communication interface between the towing and towed vehicles that had been prepared by TF TPMSTI (ECE/TRANS/WP.29/GRBP/2021/6 and GRBP-73-03).

20. GRBP adopted the proposals and requested the secretariat to include them in a revised document ECE/TRANS/WP.29/2021/10/Rev.1 for consideration and vote at the March 2021 sessions of WP.29 and AC.1 as part of a draft new 01 series of amendments to UN Regulation No. 141.

48. The GRBP Chair reported on the results achieved by GRBP at its seventy-third session (for details, see the report of the session ECE/TRANS/WP.29/GRBP/71).

49. He mentioned that GRBP had adopted modifications to the draft 01 series of amendments to UN Regulation No. 141 (Tyre pressure monitoring system). He recalled that the draft 01 series of amendments would still be addressed by WP.29 this week (ECE/TRANS/WP.29/2021/10) and encouraged the World Forum to consider instead a revised consolidated proposal ECE/TRANS/WP.29/2021/10/Rev.1 under agenda item 4.6.9.

50. He also pointed out that GRBP had agreed to update the Terms of Reference of its two IWGs on Measurement Uncertainties (MU) and on Wet Grip Performance for Tyres in a Worn State (WGWT). WP.29 noted that the revised Terms of Reference were annexed to the report of GRBP at its seventy-third session.

51. WP.29 endorsed the updates of the Terms of Reference of the IWG MU and IWG WGWT.

78. The World Forum considered draft amendments under agenda items 4.6.1 to 4.6.7. and recommended their submission to AC.1 for voting, subject to the following corrections of ECE/TRANS/WP.29/2021/8 under agenda item 4.6.6 (WP.29-183-06):
In paragraph 4.4.1., replace “markings” with “approval mark”.
In paragraph 9.1., delete from the proposal (i.e. keep the paragraph in its current form).

79. The Chair of GRBP presented draft amendment proposals contained in documents ECE/TRANS/WP.29/2021/3, ECE/TRANS/WP.29/2021/10 and Rev.1, ECE/TRANS/WP.29/2021/11 under agenda item 4.6.8 to 4.6.10., to amend UN Regulations Nos. 41, 141 and 142. The World Forum recommended their submission to AC.1 for voting.

18. The expert from Germany proposed amendments with a view to adapting UN Regulation No. 124 to the current requirements for type approvals (ECE/TRANS/WP.29/GRBP/2021/7). GRBP adopted this proposal and requested the secretariat to submit it for consideration and vote at the June 2021 sessions of WP.29 and AC.1 as a new Supplement to UN Regulation No. 124 .

21. The expert from Germany proposed amendments with a view to adapting UN Regulation No. 124 to the current requirements for type approvals (GRBP-72-04). GRBP invited him to submit an official document for consideration at the next session.