NMPB-routes-2008: The revision of the french method for road traffic noise prediction
Résumé
The revision of the French method for road traffic noise prediction (NMPB-Routes-2008) is now published. The major principles of NMPB-Routes-2008 are outlined. The most important modifications regarding the source are the reduction of its height and the introduction of two different spectra. In this complete revision, the main change is the replacement of the ISO 9613-2-based ground attenuation formula in downward-refraction conditions by the formula for ground attenuation in homogeneous conditions of NMPB-Routes-1996 with corrected heights in order to take into account the mean curvature of rays (refraction) and its scattering (turbulence). NMPB-Routes-2008 adds an attenuation term for an occasional cutting embankment. Regarding diffraction the dif formula is now more suitable for low height barriers. The validation of NMPB-Routes-2008 with respect to experiment is presented. It is based on measurement campaigns on 6 sites with complex geometries and shows that the predicted noise levels obtained from NMPB-Routes-2008 are significantly closer to experimental results than in the case of the original method. S. Hirzel Verlag.