Introductory notes

The European Commission (DG GROW) has assigned EMISIA (GR), RICARDO (UK), TNO (NL), and HSDAC (DE) with the task to investigate and propose "new sound level limits at Euro 5 step of L-category vehicles", taking into account the evolution of sound levels of approved vehicle types, the citizens’ needs, and the technical and economic feasibility in the medium term range. Should this be necessary to you, the contact person in the European Commission is Mr. Andreas Vosinis (

The new sound emission level limits to be proposed will be accompanied by an appropriate timeframe for their application. The outcome of this study is expected to cover the necessity for the adoption of the new sound emission level limits in the EU regulation. The ultimate objective is to protect the environment and human health, by providing an improved sound level range of L-category vehicles and contributing in the reduction of the so-called ‘noise pollution’ and real-world traffic noise.

Almost a year ago, we had disseminated a questionnaire in the framework of a relevant project entitled “Study on enhanced sound requirements for mopeds, quads and replacement silencers of L-category vehicles”. The aim of that project was to perform due diligence on UN Regulations Nos. 9, 63, and 92 before considering their accession into the EU regulatory framework, and the questionnaire focused on issues like the type approval procedure, market surveillance and enforcement, anti-tampering measures, replacement silencers, etc. Our consortium would like to thank all interested parties that answered it.

Overview of the questionnaire
On top of the previous questionnaire disseminated last year, and since our current study focuses on new Euro 5 sound level limits, the questionnaire at hand aims at collecting your input with regard to the following aspects of sound emitted from L-category vehicles:
_ Technical issues related to sound limits: current technology used, technical differences related to sound control of different vehicle types, type approval testing procedure and conditions, frequency and reason for use of absorbent fibrous materials, the estimate for new sound limits, technical difficulties expected, impact of ASEP introduction, etc.
_ Contribution of L-category vehicle components to sound emissions: if exhaust is the main sound source, what is the contribution of other components and non-exhaust sources, like e.g. the intake, engine, transmission system, etc. More engineering insights on technology possibilities to contribute in reducing sound emissions.
_ Cost/benefit impact from the expected sound emissions reduction: costs associated with the introduction of new sound emission level limits, environmental benefits, improved citizens’ health, focus on urban and quiet rural areas, etc.

What we need from you – guidelines
_ Please feel free to answer only the questions you are familiar with. We understand that there is a diverse set of questions and some of them are highly technical, so it is ok if you do not address all of them.

_ You can substantiate your input (if possible) by documents, references to literature and practical examples, own measurements, or any other suitable information that can help improve the legislation.

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f you think it takes too much time to fill in the questionnaire or that it does not provide the framework of what you would like to respond to, please arrange a phone call with Dr. Giannis Papadimitriou (,  +30 2310 473374) or Dr. Leonidas Ntziachristos (,  +30 2310 996003).

Feel free to forward the questionnaire to other relevant experts in your company/institution.

We would appreciate receiving your feedback until 8 January 2017.