Relating On-Board Sound Intensity Tire Noise to Heavy Truck Pass-by Noise

Heavy truck pass-by noise was measured at 20 different sites in the U.S. featuring different pavements, speeds, and roadway grades. At each site, tire noise was also measured following the T 360 procedure specified by the American Association of State Highway Transportation Officials, Standard Method of Test for Measurement of Tire/Pavement Noise Using the On-Board Sound Intensity (OBSI) Method. The average truck speed at the 20 sites ranged from 46.2 to 109.1 km/hr, while at any given site, the one-third octave band spectrum levels typically displayed a range of 10 dB. Comparing the pass-by levels to the other three variables, the OBSI results most closely follow the truck pass-by levels, with a regression slope of less than 1.1 to 1. The dominance of truck tire noise was also demonstrated with beamforming measurements made at each site for each pass-by. The results of the OBSI and pass-by measurements are presented along with the results from a previous truck tire OBSI study.