Report

R157: The life cycle economic feasibility of noise barrier caps Y2

Authors
David Schultz
Robert Kochhan
Khodamorad Nabaki
Michael Kurniawan
June 1, 2026

This project assessed the life-cycle economic feasibility and structural requirements of various noise barrier caps, also referred to as 'noise caps’, to provide a basis for selecting efficient noise mitigation strategies. Noise caps are specialised extensions designed to be mounted on the top edge of conventional roadside noise barriers. The fundamental motivation for investigating these devices is that they aim to provide additional noise reduction, or insertion loss (IL), without demanding a significant increase in the barrier's height or requiring the barrier to be moved closer to the noise source (the road) or noise sensitive receiver (for example a dwelling). Noise caps are therefore considered as a potential solution where simply constructing taller barriers is undesirable due to associated factors such as visual intrusion, or complex structural demands. By modifying the path of sound waves and increasing the acoustic shadow zone, these caps seek to offer a more efficient, feasible or aesthetically acceptable mitigation solution.

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