Standard Practice for
Quantifying Roughness of Pavements
AASHTO Designation: R 43M/R 43-07
1.1.This 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 lRI statistics is reported as the roughness of the pavement section.
1.2.The practice recognizes the need for a quality assurance (QA) plan and proposes guidelines for the development of a QA plan.
1.3.Measurements of profile are made in accordance with ASTM E 950.
If any part of this practice is in conflict with its references made, such as ASTM standards, this practice takes precedence for its purpose.
1.4.The values in either SI units or inch-pound units are to be regarded separately as standard. Within the text, the inch-pound units are shown in parentheses.
The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other.
Combining values from the two systems may result in nonconformance with the specification.
1.5.This practice does not purport to address all of the safety concerns, if any, associated with its use.
It is the responsibility of the user of this practice to establish appropriate safety and health practices and determine the applicability of regulatory limitations
related to and prior to its use.
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