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.