Author(s): Kokkonen Jarno
During the implementation process of the CNOSSOS-EU noise model, many questions has been raised. There are inconsistencies in the directive, but most of the questions are related to acquisition of initial values and their validity. CNOSSOS-EU default rolling and propulsion noise factors are not usable in Nordic conditions and the national factors had to be defined. The Nordic A and B coefficients for rolling and propulsion noise are based on measurements in Sweden and Finland and already implemented in Nord2000 noise model. Also Nord2000 road surface correction can be converted to CNOSSSOS. CNOSSOS railway model implementation is more challenging and lots of work must be done before Finland has reasonable values for CNOSSOS source model. Without accurate and validated national source values only propagation was calculated with CNOSSOS and sound power levels had to be defined with current Nordic model. CNOSSOS calculated noise levels look quite different when compared to the current Nordic models’ results. However, the most significant difference is related to the new assessment method and not for sound power level or propagation part.
Name: Mr Jarno Kokkonen