Study to prepare the adaptation to technical progress of EU requirements on silencing systems containing acoustically absorbing fibrous materials for vehicles of categories M1,M2,M3,N1,N2,N3 : final report

This is the final report of the project entitled "Study to prepare the adaptation to technical progress of EU requirements on silencing systems containing acoustically absorbing fibrous materials for vehicles of categories M1,M2,M3,N1,N2,N3", related to the usage of acoustically absorbing fibrous materials in automotive silencers and their effect on exhaust sound levels. The main objective of the study was to prepare the adaptation to technical progress of EU requirements on silencing systems containing acoustically absorbing fibrous materials for M and N road vehicles, by investigating the technical and financial feasibility of such systems and by identifying whether fitting such systems to these vehicle categories and proposing improved testing conditions, leads to the achievement of improved sound emissions performance. The study included a stakeholder survey in order to take into account the opinion of the industry and national authorities, a vehicle test, and a cost-benefit analysis.