sonROAD18: Swiss Implementation of the CNOSSOS-EU Road Traffic Noise Emission Model

Abstract

To account for recent developments in the fleet of road vehicles and to extend the allowable speed range, Switzerland has updated its road traffic noise emission model under the acronym sonROAD18. The model description is based on the formalism of CNOSSOS, however specified in third octave bands. In extension to the declaration of an average sound power radiated by a single vehicle, statistical indicators are provided as well to describe individual variations. Omnidirectional radiation characteristics is assumed in the horizontal plane whereby the emission is defined as equivalent sound power of a point source that induces a correct sound event level. In vertical direction, spectral corrections are applied to account for the reduced emission strength under large elevation angles. The accuracy of the model is specified for different scenarios with respect to the level of detail of available input parameters.