4. The expert from IMMA proposed to delete the last sentence in paragraph 1.3.2.1., since the scope of the 04 series of amendments to Regulation No. 41 did not cover motorcycles with a sidecar (L4 category of vehicles) (ECE/TRANS/WP.29/GRB/2017/4). GRB adopted this proposal and requested the secretariat to submit it to the World Forum for Harmonization of Vehicle Regulations (WP.29) and to the Administrative Committee (AC.1) for consideration and vote at their March 2018 sessions as a draft Supplement 6 to the 04 series of amendments to Regulation No. 41.

5. The expert from EC introduced the ongoing study on Euro 5 sound level limits of L-category vehicles (GRB-66-15) with the aim to investigate the potential for new sound limits of L-category vehicles. He explained that the study takes into account the evolution of sound levels of road vehicles (actual vehicle testing), citizens’ needs and stakeholders interest (feedback gathering), and technical and economic feasibility in the medium term (cost-benefit analysis). The experts from Germany, Netherlands and OICA pointed out that only reducing the sound limits for new vehicles would not achieve the desired results unless accompanied by measures to combat illegal aftermarket products (silencers). The Chair proposed to resume this discussion once the results of the study would be available.

6. The expert from Germany highlighted the existing problems with and possible solutions for the noise emissions of L-category vehicles, including non-original replacement exhaust silencer systems (NORESS) (GRB-66-12). According to him, there was a gap between quiet vehicles during the type approval process and loud vehicles on the streets, because of manipulation with silencers, loopholes and grey areas in the United Nations and the European Union (EU) regulations. For better enforcement of compliance of vehicles in use with the sound limits and as an alternative to measurement of stationary noise, he proposed a simplified pass-by noise test which could be used for road-side checks and periodic technical inspections of type approved motorbikes and their NORESS (GRB-66-17). The experts from France and the Netherlands supported the need for stronger enforcement. The expert from IMMA volunteered to contribute to developing the pass-by noise test.

7. The expert from Japan presented an overview of the current noise regulations in Japan and their expected development in the future (GRB-66-08). In particular, he pointed out that Japan was reviewing the limit value for the acceleration noise of two-wheelers and hoped that these domestic considerations could be synchronized with the GRB deliberations on new limit values in the 04 series of amendments to Regulation No. 41.