The institute deals with the propagation of traffic noise from both road and rail. It develops and operates simulation models that describe the system of atmosphere, topography and sound waves in a consistent manner. The propagation models are able to simulate refraction, absorption and scattering of sound waves in the inhomogeneous atmosphere. Reflection and diffraction at the topography (ground, hills, buildings, vegetation barriers, etc.) are considered too. The structure of the topographically modified atmosphere is determined with meteorological models such that a coupled meteorological-acoustical modeling system is generated.