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UNECE World Forum for Harmonization of Vehicle Regulations tightens vehicles noise limits and adopts new test procedure to measure them

With rapid urbanization and growth of vehicle's fleet, more and more people are suffering from noise pollution. According to a recent study, 25 per cent of European citizens are exposed to average noise above the threshold established by WHO (55 dB) and road traffic is its main source. Thus, reduction of traffic noise is essential to improve the health and quality of life of people.

On 24 June, the UNECE World Forum for Harmonization of Vehicle Regulations (WP.29) made a significant step towards achieving this goal by adopting a comprehensive revision of UN Regulation No. 51 on vehicle noise.  

The revised UN Regulation introduces reduced noise limits for vehicles (passenger cars, light commercial vehicles, light and heavy trucks and buses) that will enter into force in three steps from 2016 to 2024.

It also introduces a new test procedure which more realistically reflects the exterior noise of vehicles in typical urban traffic situations. The test procedure is based on performance and not on design criteria. Therefore, it can apply to any current or future propulsion technologies, including combustion, fuel cell, hybrid or pure electric vehicles. The revised UN Regulation also contains requirements to ensure that noise levels emitted by vehicles in real driving conditions do not significantly deviate from the test measurements.

The new revision is the result of an extensive review of different traffic conditions worldwide and of vehicles operated on a variety of urban roads in Europe and Asia. To ensure the widest geographical recognition of the revised UN Regulation No. 51, it inter alia addresses specific categories of commercial vehicles available on the Japanese and Chinese markets.

UN Regulation No. 51 originally came into force in 1982 and has been amended several times. Its application led to a tremendous reduction in noise levels with the sound energy emissions from vehicles dropping by some 90 per cent (10 dB).  

Note to editors

The World Forum for Harmonization of Vehicle Regulations (WP.29) is a Working Party within the UNECE Inland Transport Committee. It manages three global Agreements on vehicles. Any country that is member of the United Nations may participate in the activities of the World Forum and accede to the Agreements.

A comprehensive overview of WP.29 activities, beginning with a brief history from its inception as a regional forum through its transformation into a world forum, is available at:

The 1958 Agreement and its annexed UN Regulations contain provisions (for vehicles, their systems, parts and equipment) related to safety and environmental aspects. They include performance-oriented test requirements, as well as administrative procedures. They address issues such as type approval (of vehicle systems, parts and equipment);   conformity of production (i.e. the means to prove the ability, for manufacturers, to produce a series of products that   match the type approval specifications); and   mutual recognition of the type approvals granted by Contracting Parties.

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