Roughness of unpaved roads: Estimation and use as an intervention threshold. http://dx.doi.org/10.3141/2101-02

Abstract

One of the main tasks of the Chilean Dirección Nacional de Vialidad and its regional and provincial secretariats is to determine the maintenance requirements of its roads. In developing countries, most roads managed under this process are unpaved. The traditional way of determining maintenance requirements relies on the criteria applied by whoever inspects the roads. To improve this process, the present work proposes an easy, objective method for determining the conservation requirements of unpaved roads. Roughness thresholds are proposed because they adequately summarize the functional characteristic of this kind of road. Roughness thresholds were determined for different road types after consulting public-, private-, and academic-sector experts who proposed international roughness index (IRI) values based on the characteristics of each road. To measure the roughness of unpaved roads, the use of a response-type roughmeter is recommended. When this type of equipment is not available, it is proposed that IRI be estimated with data obtained from visual inspection. The main distresses of unpaved roads and IRIs were correlated by using data collected from 61 test sections.