Proposal to update and clarify the text and to align the text with other UN Regulations and adopted proposals.

Presentation concerning the proposals to clarify and update the texts and to align their provisions and terms.

Based on the outcomes of a European Commission study, proposal to clarify the text and align its provisions with other vehicle sound regulations, especially UN R41, including to replace references to “two wheeled moped” with the term “L1 category vehicles” (and consequently to replace references to “moped” with “vehicle”) and to replace the term “noise” with “sound” (except for references to background noise) throughout the regulation. It proposes improved terminology and definitions, including new ones, improved sound emission testing conditions and procedures. It also introduces sound emission measurement through new testing of in use vehicles in motion.

Proposal to clarify that conditioning of a silencing system is necessary only in cases where exhaust gases come into contact with silencer fibrous materials.

Explanation of recommendations developed for the European Commission by LAT, TNO, Heinz Steven, and TÜV Nord for the improvement of the regulations with regard to additional sound emission provisions.

Based on the outcomes of a European Commission study, proposal to clarify the text and align its provisions with other vehicle sound regulations, especially UN R41, including to replace references to “two wheeled moped” with the term “L1 category vehicles” (and consequently to replace references to “moped” with “vehicle”) and to replace the term “noise” with “sound” (except for references to background noise) throughout the regulation.

UN R51 specifies that conditioning of a silencing system is necessary only in cases where exhaust gases come into contact with silencer fibrous materials. This proposal would apply the same concept in L category noise regulations.

Overview of discussions for the future development of vehicle noise regulations prepared by the GRB secretariat.