None of the standards designed for the calculation of environmental noise cover the complexity of the real world. All standards stop with screening over an obstacle. Some explain multiple screening for two independent screens but do not recognize that a building with a front and a back are not two completely independent screens. Most of the standards do not explain wind and weather sufficiently. In any case, there are many gaps in the common standards.
SoundPLAN has solved some of the geometrical shortcomings representing the real world. For openings of tunnels from roads and railways, for example, there is a dedicated tunnel object allowing the user to enter the geometry of a tunnel and define how far into the tunnel absorptive material is used. From these parameters, the program calculates the emission from the tunnel in the normal calculation. Tunnel objects are unique to SoundPLAN.