Refining the CNOSSOS-EU calculation method for environmental noise

By the first of January 2019 all member states are required to transpose the CNOSSOS-EU calculation method (EU directive 2015/996) in their legislation. In preparation a study was conducted in 2017 to evaluate the new calculation method. Part if this evaluation was to see if the method could also be used to replace the Dutch national method. In this study we found errors within the method that, if implemented, would lead to implausible results. The results of this study were presented to the EU commission and the Noise Regulatory Committee. As a result an EU working group, chaired by the Netherlands, was established to study and propose amendments to the method. This EU working group has found numerous issues. Some issues are about unclear text, which may lead to different interpretations of the method. Other issues are more fundamental. They are clear errors in the method. One serious example is the problem that occurs with multiple diffractions in favourable conditions. For almost all the issues a solution is drafted. A report is finalized where these issues and proposed solutions are discussed. In this paper we will present issues, solutions and the remaining issue.