Effects of Noise Limits for Powered Vehicles on Their Emissions in Real Operation

The method of measuring the noise of powered vehicles is directed primarily at reducing engine and transmission noises as the most powerful sub-sources. But tyre-road-noise is also an important element of the overall nuisance so that a reduction in the noise limits for the homologation test is no longer necessarily associated with a reduction of noise emissions in traffic.

Special test series on random traffic samples covering the entire range of vehicle types were carried out in order to reassess noise emissions in real traffic.