The document provides follow-up information from the SLR 77th session. SLR-77-06/Rev.1 corrects errors and omissions in Reg. 150 and will supersede GRE-94-02, potentially merged with the proposal deleting UI in R150-01 for WP.29 submission in November 2026. Four baseline documents for Stage 2/Step 2 work (SLR-77-08/Rev.1, SLR-77-09, SLR-77-10, SLR-77-07 for Regs. 48, 53, 74, 86 respectively) will be submitted to GRE-94 with presentation slides. SLR agreed to keep Par. 6.21 on conspicuity marking and to renumber paragraphs 5.5 to 5.36. Old transitional provisions are documented separately. Apparent surface definition will replace light-emitting surface. Direction indicator visibility requires further study. Harmonisation text prohibits non-mentioned lamps unless compliant with national requirements. Eleven informal documents will be submitted to GRE-94.
Proposal to amend, restructure, and clarify UN R86:
This presentation analyzes RD-ASEP model performance using test run data from Annex_9_test_runs where both left and right sound were measured. Current model shows 1.3% of measurements above L_exp; without the 2 dB margin this increases to 8.4%. Model overestimates at low speeds and underestimates at higher accelerations. Tyre rolling sound parameters have most influence on results and dominate most of the data set. Optimizing all 13 parameters reduces mean absolute error from 2.1 to 1.1 dB. More high acceleration measurements are needed to reliably calibrate the dynamic component.
The IWG RD-ASEP informal group is developing a mandatory procedure for UN R51 after the monitoring phase. The Analysis Task Force determined vehicle databases and expectation model are suitable for RD-ASEP use. The Editing Task Force created a consolidated R51.04 draft incorporating R51.03 Supplements up to Supplement 11, with revised manipulation and defeat device provisions and mandatory random testing for approval. R51.04 RD-ASEP expands vehicle speed range to 0-100 km/hr, adds vehicle performance criteria, requires testing for approval, and permits random test points and any acceleration position, compared to R51.03 ASEP.
The agenda includes discussion of Terms of Reference from GRBP-78-13, procedural update from GRB-68-03, Analysis Task Force Report, Editing Task Force Report, R51.04 Issues List Review, draft R51.04 text review, Inside and Outside Boundary Condition discussions, and confirmation of next meeting date and place as August 31–September 1 in Geneva, Switzerland.