Urban densification is leading to a significant increase in road traffic noise, severely affecting urban quality of life. Green roofs and facades offer promising potential for reducing the sound reflection of road traffic noise and improving the urban living environment. Vegetation and substrate layers on buildings can function as porous surfaces and reduce sound reflection, particularly at high frequencies, depending on their absorption coefficient and surface proportion.

The growing importance of climate-friendly urban planning has increased the demand for green buildings in Germany. In response, authorities have introduced various municipal instruments to support building greening programs.

This research examines the impact of estimated green building developments on sound propagation in urban areas. The trend towards green buildings up to 2050 is analysed and translated into forecasts using statistical methods. The forecasts are converted into realistic planning situations, the associated noise immission plans are simulated and the level differences are compared with the current situation.  Additionally, a frequency-dependent analysis is conducted.

Results indicate that despite a considerable amount of green buildings by 2050, no perceptible overall noise reduction is expected. However, reduced high-frequency sound reflection may alter noise perception. These aspects should be considered in future urban noise mitigation strategies.