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Pages 1-5

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From page 1...
... The objective of this study was to use noisesource mapping techniques to accurately localize, identify, and quantify the noise sources on typical commercial trucks operating in the actual roadway environment. The scope of work for this project included design, development, experimental demonstration, and validation of a practical technology for truck noise-source localization and distribution under actual operating conditions.
From page 2...
... The elliptical shape was found optimal because vertical resolution of the noise source image is more important than horizontal resolution for traffic noise barrier design and also because of certain inherent horizontal resolution of the noise source image during a passby. The microphone array parameters assuring the optimal performance were selected for implementation in the array hardware.
From page 3...
... (b) The results of these measurements for 59 heavy truck passbys and 4 medium truck passbys were analyzed in detail, with acoustic images and spatial noise source distributions obtained to define and interpret the noise source levels and sound paths from the engine, tires, exhaust, and other body components.
From page 4...
... Sound distribution images and maps obtained during truck passbys permitted examination of the time histories and spatial distributions of sources, as well as an analysis of the noise paths from the engine, exhaust, muffler, tires, and other body components for various trucks. Statistical analysis of the vertical distribution of noise sources indicated that for the majority of truck passbys measured at highway speeds on an in-service highway, tire–pavement interaction was the dominant source generating sound close to the pavement.
From page 5...
... as interim source height adjustments to the reference emission levels in the FHWA Traffic Noise Model. • Traffic noise prediction models updated using the noise source distributions obtained in the current study can serve as a resource for state and federal agencies to examine the effectiveness of highway noise mitigation strategies, such as the use of quieter pavements or barrier design.

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