The effects of vegetation on reducing traffic noise from a city ring road

This study was designed to investigate the reduction of road noise by vegetation along the ring road of Thessaloniki. Road noise was measured at two sites, one through a belt of trees and the other on a grass-covered ground. A total of 245 measurements were taken from each site over a two-month period and expressed as differences in LAeq. Also measurements of the number of vehicles per minute, the type of vehicles and analytic description of vegetation were taken at both sites. The results showed higher noise reductions through the belt of trees than over the grass-covered ground. According to the results of this research the largest reduction, 6 dB, was seen in the Pinus brutia belt of trees, 60 m away from the road. This noise reduction is considered satisfactory due to the tree belts extending on both sides of the ring road.