31. The expert from ISO reported on the progress of standard ISO 362-3 on indoor testing of pass-by noise (GRB-64-07). The expert from OICA stressed the importance of including indoor testing as an alternative to type approval tests of Annex 3 to Regulation No. 51, in particular for vehicle manufacturers in countries where the local weather conditions allow the use of outdoor test tracks only for a limited period per year. The expert of Germany pointed out that, at this stage, it would be premature to replace type approval tests with indoor testing. To make progress, GRB invited the experts from ISO and OICA to prepare for the next session an informal document with draft amendment proposals to Regulation No. 51 that would include ISO 362-3.

32. The Chair presented a revised list of possible issues for the future GRB activities compiled at the third informal meeting in July 2016 (GRB-64-08). The expert from Japan proposed modifications to the time limits of some activities listed in this document. The expert from France presented proposals to improve efficiency of road vehicle noise Regulations by tackling such issues as day-to-day and track-to-track dispersion between measurements and different interpretations of the same text (GRB-64-15). The expert from EC proposed to include three additional points related to L-category vehicles (GRB-64-17). The expert from OICA reported on a meeting between ETRTO and OICA which concluded that a harmonized test procedure for tyre and vehicle noise measurements would be beneficial for industry and environment. Finally, GRB invited all experts to submit their comments in writing to the Chair and requested the Chair to update the list accordingly.