AASHTO R 43-13 (2021)

This standard practice describes a method for estimating roughness for a pavement section. An International Roughness Index (IRI) statistic is calculated from a single longitudinal profile measured with a road profiler in both the inside and outside wheelpaths of the pavement. The average of these two IRI statistics is reported as the roughness of the pavement section.

The standard practice recognizes the need for a quality assurance (QA) plan and proposes guidelines for the development of a QA plan.

Measurements of profile are made in accordance with ASTM E 950. If any part of this standard practice is in conflict with its references made, such as ASTM standards, this standard practice takes precedence for its purpose.

This standard practice is a combination of two former provisional standard practices - PP 37 Standard Practice for Determination of International Roughness Index (IRI) to Quantify Roughness of Pavements and PP 37M Standard Practice for Quantifying Roughness of Pavements.