scope:

This test method describes a procedure for measuring the influence of road surfaces on highway traffic noise. The Statistical Isolated Pass-By (SIP) Method 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 standard is intended for use by acoustic professionals. Competency with acoustical measurement and analysis techniques is assumed.

This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns associated with its use. It is the responsibility of the user of this standard to consult and establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

The quality of the results produced by this standard are dependent on the competence of the personnel performing the procedure and the capability, calibration, and maintenance of the equipment used. Agencies that meet the criteria of R 18 are generally considered capable of competent and objective testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with R 18 alone does not completely assure reliable results. Reliable results depend on many factors; following the suggestions of R 18 or some similar acceptable guideline provides a means of evaluating and controlling some of those factors.