There is now a movement in the united states toward standardizing road roughness measurements by using a scale called the international roughness index (iri). The iri was defined by the world bank (based on earlier work performed for the nchrp) and is required by the federal highway administration (fhwa) for the roughness database of the highway performance monitoring system (hpms). The iri is definedas a roughness description for a single wheeltrack profile, obtained by using a quarter-car model with certain specified parameter values. A related roughness measure is obtained by using both wheeltrackprofiles as inputs to the same computer algorithm used for the iri.This analysis is mathematically equivalent to a half-car model and produces a roughness measure called the half-car roughness index (hri). There is currently a mixture of iri and hri data being measured in the united states. The two analytic methods are so similar in concept that many ractitioners are not aware of the difference betweenthem. As a result, there has been occasional confusion and error when data are reported. The purpose of this paper is to identify and discuss the differences and similarities between iri and hri. The paper also summarizes technology (automated profiling systems) used to measure iri and hri. This paper appears in transportation research record no. 1215, Pavement management and rehabilitation.
Samenvatting