Mapping Heavy Vehicle Noise Source Heights for Highway Noise Analysis (2017) / Chapter Skim
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3 Problem Statement and Objectives Heavy vehicles (i.e., trucks and buses) contribute substantially to overall traffic noise levels -- noise from one heavy truck is equivalent to noise from about 10 passenger cars.
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4 Mapping Heavy Vehicle Noise Source Heights for Highway Noise Analysis now routinely advertise systems for performing noise source identification and, in two cases, specifically for identifying sources under vehicle pass-by conditions.3,4,5 There is also some indication that acoustic beamforming is being used in some vehicle noise development work.6,7 The recent literature, including national and international conference proceedings, published papers, technical applications notes, and the internet, was searched, but this search yielded no new research directly related to noise source localization for in-service heavy trucks. Several applications of acoustic beamforming for source identification in pass-by noise were found.
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Background 5 The results at this speed were similar to the 56 mph case, except that at a lower frequency range (175 to 196 Hz) , exhaust noise was more indicated as a source.10 Beamforming methods have also been recently used for noise source identification in laboratory facilities in which pass-by conditions are simulated.
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6 Mapping Heavy Vehicle Noise Source Heights for Highway Noise Analysis measurement results in a second Interim Report. In Phase III, the researchers analyzed the results of the first two phases to develop proper weighting of the one-third octave band source distributions to account for their contribution to overall sound pressure level.
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