Pavement management in urban areas requires the identification of appropriate roughness indicators and of related acceptability thresholds. The use of the international roughness index (IRI) is not suitable for urban areas owing to a number of problems. The available length of homogeneous sections is often much shorter than the typical 320 m used in the World Bank experiment that led to the IRI classification. The speed is considerably lower than the 80 km/h considered for the IRI quarter car model. Also, the type of paving materials used in urban areas can be considerably different than the ones used in rural areas, resulting in a different type of roughness (as in the case of stone pavements). Furthermore, the acceptability levels in urban areas need to be defined according to the different perception of the user and additional environmental constraints. Within the Interazione Ambiente Sicurezza nel Progetto delle Infrastrutture Viarie project funded by the Italian Research and University Ministry, an extensive study has been conducted to define a roughness index suitable to represent urban streets and to identify acceptability thresholds. For this purpose, a number of urban sections with different pavement surfacing and age have been identified, and on each section the profile has been measured. To identify user perception toward the different pavement conditions, a rating procedure has been defined, and a panel rating has been performed on each section.
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