Installing an On-Board Sound Intensity (OBSI) frame to the wheel hub of a noise test vehicle. The frame suspends two precision microphones 3” from the pavement and 4” from the tire sidewall while the vehicle collects data at 60 mph. The OBSI gear is used to measure noise at the pavement/tire contact point and thereby evaluate the acoustic performance of the pavement. OBSI affords a directional measurement of noise. The measurements are unaffected by traffic and reflective barriers at the roadside, which allows testing at any time of the day in urban areas.
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