Consolidation in Supplement 11 includes: clarification of Verification/Adjustment and editorial corrections with transitional provisions (GRBP/2025/20 with GRBP-82-07); correction of Tyre Road Sound Measurement for Indoor-Testing (GRBP-82-22); introduction of ASEP in Annex 7 for BEVs and HEVs (GRBP/2026/4 with GRBP-83-xx); update of ISO standards in Annex 3 and Annex 8 (GRBP/2026/5 with GRBP-83-xx); and reference for Power Definition regarding new UN R177 (GRBP/2026/13). The consolidated version of Supplement 11 is to be submitted to the 199th WP.29 in June.

Proposal to supersede document GRBP/2026/4 intended to introduce a “default mode”, to specify requirements to be applied to the emission of Enhanced Exterior Sound (EES), with corresponding transitional provisions, and to draw a limit curve to introduce electric vehicles and hybrid electric vehicles that can be propelled without an internal combustion engine operating in the scope of ASEP (Annex 7).

Proposal to amend para. 6.2.1.1. to permit testing of vehicle sound either indoors or outdoors with equivalent results, add new Annex 11 specifying indoor testing provisions, amend Annex 1 to insert para. 8.5. and 8.5.1. requiring documentation of test method selected, amend Annex 3 para. 1. to specify sound level meter requirements for indoor testing per IEC 651 and IEC 61672-3, amend Annex 3 para. 1.1.1. to provide calibration procedures for indoor testing per IEC 942:1988, amend Annex 3 para. 1.3. to exempt wind speed monitoring for indoor facilities, amend Annex 3 para. 2.1. and add para. 2.1.4. to specify outdoor and indoor test site requirements per ISO 362-3:2022 and ISO 26101, add para. 2.1.5. specifying indoor ambient conditions, add para. 2.2.7. addressing test mass for indoor dynamometer testing, amend Annex 3 para. 3. to specify outdoor and indoor test procedures per ISO 362-3:2022 Variant A, amend Annex 3 para. 3.1.1. to clarify outdoor testing microphone placement, add para. 3.1.1.4. defining virtual lines and simulated vehicle speeds for indoor testing, and renumber former paras. 3.1.1.4. and 3.1.1.5. as 3.1.1.5. and 3.1.1.6.

Rationale for Figure Part B.5 of GRBP-84-36-Rev.1

An improvement intended to increase vehicle robustness in Annex 3 creates more difficulties in RD-ASEP assessment. Small variations in Annex 3 parameters may result in unexpected substantial exceedances in Annex 7. Minimal changes in the calculated tyre share at the anchor point may cause vehicles to fail Annex 7. The regulation should ensure realistic test effort and workload for compliance verification, as current requirements may require up to 180 combinations per type across test tracks, temperatures, driving modes, and tyres.