Traffic noise reduction attributed to roadside vegetation: ohio case study

This paper reports the findings of a research study which examined the noise reduction associated with roadside vegetation. A case study location along a major freeway in Columbus, Ohio, was utilized. Noise measurements were obtained at two locations in a neighborhood adjacent to the freeway. The neighborhood was partially shielded from the freeway by a stand of bushes and trees typical of roadside vegetation in Ohio. One location with high-density vegetation was completely shielded from the freeway while the second had lower-density vegetation with some direct line-of-sight downstream of the position. Noise measurements at the site were conducted in September 2019 on an average weekday under typical meteorological conditions for the region. Measurements were obtained simultaneously at each position to permit direct comparison of the noise reduction. Analysis indicated that the noise reduction attributed to the vegetation was approximately 3.0 dBA with an additional 1.0 dBA of reduction at the high-density position. Models of the site using FHWA TNM indicated that the modeled noise reduction was lower than what was measured in the field. The results of this case study add the body of knowledge on the topic of traffic noise reduction attributed to the presence of roadside vegetation.