Re ECF Project: 2011-44

Project Title: On the Study of Effect of Aesthetics Appearance of Vegetated Noise Barriers on Noise Annoyance Moderation

Applicant: Dr. C.K. Chau of The Hong Kong Polytechnic University

Total Approved Grant: $492,200.00

Duration: 1/3/2013 to 28/2/2015

Project Status/Remarks: Completed

The project aims to evaluate the effects of aesthetics appearance of vegetated noise barriers on annoyance moderation and investigate whether the configuration of vegetation has an influence on their annoyance moderation effect. It also aims to identify the most cost-effective configuration for the vegetated noise barriers from the perspective of lifecycle costs.

Summary of the Findings/Outcomes:
Two probability models were successfully formulated for describing the relationships between the prevalence of high noise annoyance, and vegetative noise barriers and other personal characteristics. Our results determined that the prevalence of high annoyance could be lowered by placing climbers, and/or trees near barriers. Trees covering barriers would lower the prevalence when noise level was above 70 dB(A). For climbers, the prevalence of high annoyance lowered with 50% covering, and further lowered with 90% covering. This is in contrast with tree coverage, for which the prevalence of high annoyance lowered with 50% covering but increased with 90% covering. With both trees and climbers were used, the optimal combination that produced the lowest prevalence of high annoyance was when 50% of barriers was covered by climbers and trees. In addition, the cost effectiveness of various vegetation configurations was also estimated. The configuration of trees covering half of noise barriers was found to be the most cost effective option.