Open-source software to calculate industrial, railway, and road traffic noise

Abstract

Dutch noise legislation provides instructions and formulas to calculate noise exposure levels on a similar level to Cnossos or ISO 9613-2. The instructions are implemented in commercially available software packages. Each implementation includes a pathfinder and a sound propagation/attenuation module. Whilst the attenuation is described in detail in the legislation, the pathfinder is not and its design is left to the software company. Currently there are only proprietary, closed-source implementations available. That is going to change. Based on a previously closed-source solution, we are working towards an open-source, national implementation to calculate noise levels based on 3D model input. We implemented the updated Dutch calculation method and improved the pathfinder. For example, this now includes sloped barriers. Only the calculation core is part of this project: the development of a graphical user interface is not planned, but can be provided by others. Also, other implementations of the Dutch noise calculation directive can still co-exist next to our open-source solution, since the legislation only specifies the instructions and has no requisite for a specific implementation. In this paper we will discuss the open-source implementation, the impact on noise modelling in the Netherlands and its potential applications outside of the Netherlands.