ASTM-E1926 Historical Revision Information
Standard Practice for Computing International Roughness Index of Roads from Longitudinal Profile Measurements

ASTM-E1926 - 1998 R03 EDITION - SUPERSEDED
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Standard Practice for Computing International Roughness Index of Roads from Longitudinal Profile Measurements
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Scope

1.1 This practice covers the mathematical processing of longitudinal profile measurements to produce a road roughness statistic called the International Roughness Index (IRI).

1.2 The intent is to provide a standard practice for computing and reporting an estimate of road roughness for highway pavements.

1.3 This practice is based on an algorithm developed in The International Road Roughness Experiment sponsored by a number of institutions including the World Bank and reported in two World Bank Technical Papers (1) (2). Additional technical information is provided in two TRB papers (3) (4).

1.5 This standard 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 standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Significance and Use

This practice provides a means for obtaining a quantitative estimate of a pavement property defined as roughness using longitudinal profile measuring equipment.

5.1.1 The IRI is portable in that it can be obtained from longitudinal profiles obtained with a variety of instruments.

5.1.2 The IRI is stable with time because true IRI is based on the concept of a true longitudinal profile, rather than the physical properties of a particular type of instrument.

Roughness information is a useful input to the pavement management systems (PMS) maintained by transportation agencies.

5.2.1 The IRI for the right wheel track is the measurement of road surface roughness specified by the Federal Highway Administration (FHWA) as the input to their Highway Performance Monitoring System (HPMS).

5.2.2 When profiles are measured simultaneously for both traveled wheel tracks, then the MRI (average of the IRI for each profile) is considered to be a better measure of road surface roughness than the IRI for either wheel track.

Note 1—The MRI scale is identical to the IRI scale.

IRI can be interpreted as the output of an idealized response-type measuring system (see Test Method E 1082 and Specification E 1215), where the physical vehicle and instrumentation are replaced with a mathematical model. The units of slope correspond to accumulated suspension motions (for example, metres), divided by the distance traveled (for example, kilometres).

IRI is a useful calibration reference for response-type systems that estimate roughness by measuring vehicular response (see Test Method E 1082 and Specification E 1215).

IRI can also be interpreted as average absolute slope of the profile, filtered mathematically to modify the amplitudes associated with different wavelengths (3).

Keywords

highway performance monitoring system; HPMS; international roughness index; IRI; longitudinal profile; pavement management systems; pavement roughness; PMS; ICS Number Code 93.080.99 (Other standards related to road engineering)

To find similar documents by ASTM Volume:

04.03 (Road and Paving Materials; Vehicle-Pavement Systems)

To find similar documents by classification:

93.080.99 (Other standards related to road engineering)

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Document Number

ASTM-E1926-98(2003)

Revision Level

1998 R03 EDITION

Status

Superseded

Modification Type

Reapproval

Publication Date

Dec. 1, 2003

Document Type

Practice

Page Count

18 pages

Committee Number

E17.33