Determination of a noise emission model for French medium-heavy vehicles

The European Directives 2002/49/EC and 2015/996 provide a common evaluation method (CNOSSOS-EU) for Member States to produce noise maps assessing environmental noise exposure. A French transposition of the Directives specifies the corrective coefficients applicable for the French road network. Previous observations highlighted significant discrepancies between measurements carried out in France on medium-heavy vehicles (category 2) and CNOSSOS-EU. However, this category of vehicles was not specifically considered in the French method NMPB2008 and their actual noise emission is undocumented. Thus, noise emission measurements have been carried out on different types of vehicles in this category (van trucks, dump trucks, bus), exploring a wide range of controlled operating conditions to separate the contributions of propulsion and rolling noise. In a second step, two traffic scenarios of category 2 vehicles, with significantly different proportions of public transport vehicles, are used to determine average emission equations in accordance with CNOSSOS-EU modeling. The noise issue between these scenarios is linked to the propulsion noise contribution, which is of main interest at urban speeds but becomes insignificant at high speeds when rolling noise predominates. The two scenario models are confronted with CNOSSOSEU variants, including the corrected model now recommended in the French regulation.