AASHTO TP 98-12

This test method describes a procedure for measuring the influence of road surfaces on highway traffic noise. The Statistical Isolated Pass-By (SIP) method of test provides a quantitative measure of the sound pressure level at locations adjacent to a roadway. The SIP method allows for the comparison of vehicle noise on roadways of varying surfaces and across studies by comparing measured sound levels to a reference noise curve.Measurements capture the sound pressure level from isolated vehicles in existing traffic. The SIP method is to be applied on roadways where measuring sound levels from single vehicle pass-by events is possible without contamination from sound from other vehicles.This document is intended for use by acoustic professionals. Competency with acoustical measurement and analysis techniques is assumed.