Evaluation of Test Variables for Onboard Sound Intensity Measurements

Abstract

As a portion of the overall research work for the NCHRP 1-44 project, an examination of test variables was conducted for the onboard sound intensity (OBSI) method of measuring tire–pavement noise at the source. The intent of this investigation was to provide guidance on test variables for users to determine the control limits needed to implement the OBSI procedure. An extensive review of literature about onboard tire noise measurement methods identified pertinent variables that could affect the repeatability and reproducibility of the measurements. The sensitivity of OBSI results to variations in pavement temperature, the configuration of the OBSI measurement fixture, tire inflation pressure, test vehicle type, test speed, and load were measured. The testing was done on both asphalt and cement concrete pavements with two different test tires: the ASTM standard reference test tire and the Dunlop SP Winter Sport M3 tire. This paper summarizes the evaluation and results of the test parameter investigation, the information obtained, and the implications for development of a rational test procedure.