Noise mitigation due to vegetation lines alongside major roads? An investigation of the acoustic effect of vegetation and its influence on the perceived noise annoyance

Vegetation lines alongside tra c routes provide a variety of positive e ects, such as visual guidance, glare, wind and snow protection. However, after the conduction of maintenance and safety cuts on the vegetation, nearby residents often report a worsening of the local noise situation. Therefore, the research project LAUB investigated the noise-mitigating properties of vegetation lines alongside major roads in Austria. In the course of the investigations, statistical and controlled pass-by measurements were carried out before and after the removal of the vegetation lines on three different sites along major roads. The recorded acoustic and visual data was analysed as well as compared, and furthermore used in an audio-visual experiment to assess the perceived noise annoyance. Together with the results from the acoustic measurements and additional sound propagation simulations, the findings from the experiment were utilized to create a guideline for maintenance and safety cuts on vegetation lines alongside major roads, with focus on noise protection aspects.