This research project performed statistical pass-by (SPB) measurements of tire/pavement noise influence on overall traffic noise levels. The pavement specimens included in the project were a conventional grind surface, an innovative grind surface, a transverse tine surface, and a burlap drag surface, all located on I-94 to the northwest of Minneapolis. Due to the high volume of traffic on the interstate highway, field measurements were not feasible. An alternative method was adopted of recording video and high-quality audio of all the traffic over several hours, along with a calibration reference level, and analyzing the recorded traffic in the office. This allowed selection of several hundred pass-by events meeting data quality requirements out of the several thousand vehicles present in the recordings. The results showed the innovative grind was clearly the quietest pavement with four-wheeled passenger cars. The results also showed the innovative grind was quieter than most other pavement surfaces, but was inconclusive against the conventional grind with dual-axle and multi-axle heavy vehicles due to insufficient data. On-board sound intensity measurements showed a dBA difference of 4.7 to 5 between the innovative grind and the pre-existing surface texture.
