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.

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.