BACKGROUND: Tire-pavement noise has become an increasingly important consideration for highway agencies as the public consistently demands that highway traffic noise be mitigated. Although noise barriers have been used for many years as a noise mitigation measure, great advances in quiet pavement technology have been introduced in recent years as potential alternatives to these barriers. Also, methods for measuring the effect such pavement technologies have on tire-pavement noise, traffic noise, and vehicle noise have been developed, and recently introduced in the AASHTO Standard Specifications for Transportation Materials and Methods of Sampling and Testing. These test methods include AASHTO Designations: TP 76, Standard Method of Test for Measurement of Tire/Pavement Noise Using the On-Board Sound Intensity (OBSI) Method, TP 98, Standard Method of Test for Determining the Influence of Road Surfaces on Vehicle Noise Using the Statistical Isolated Pass-By Method (SIP), and TP 99, Standard Method of Test for Determining the Influence of Road Surfaces on Traffic Noise Using the Continuous-Flow Traffic Time-Integrated Method (CTIM)(see Special Note A). Precision and bias statements that define limits on precision repeatability and reproducibility have been developed for TP 76 under NCHRP Project 1-44(01) but no such statements have been developed for TP 98 and TP 99. There is a need for further research to develop precision and bias statements for these test methods. These statements will help define the extent of uncertainties associated with the measurements to better interpret the results of these tests.
OBJECTIVE: The objective of this research is to develop precision and bias statements for AASHTO Standard Methods of Test TP 98 and TP 99.
STATUS: Project is complete. Research agency final report is avaialable as NCHRP Web Only Document 217 at