Experimental confrontation of medium-heavy vehicle noise emission to the cnossos-eu prediction method

Abstract

CNOSSOS-EU is the common European assessment method recommended for environmental noise prediction. Concerning road traffic noise, the sound power emission of road vehicles is described by the contribution of a propulsion noise component and a rolling noise component, according to a common approach to all vehicle types but with coefficients specific to vehicle categories. Default input values are provided in the European Directive 2015/996. Member States are invited to adapt these values to be representative of their national conditions if necessary. Vehicle category 2 concerns medium-heavy vehicles, having two axles and a minimum weight of 3.5 tons. The French reference prediction method NMPB2008 does not distinguish these vehicles within the overall heavy vehicle category and no noise emission database is presently available for this sub- category. A series of experiments has been started to collect noise data from medium heavy vehicles on French roads and vehicle fleet through SPB measurement on traffic vehicles. This is completed by CPB measurements on controlled vehicles, which offers the opportunity to separate propulsion and rolling noise contributions. The first results of this experimental approach are presented. They suggest that the French reference method NMPB2008, relying on road train emission data, overestimates the actual noise emission from vehicle category 2, whereas default input values of CNOSSOS-EU clearly underestimates it. The relative share of rolling noise and propulsion noise contributions is discussed.

Experimental confrontation of medium-heavy vehicle noise emission to the cnossos-eu prediction method