Modelling Pavement Deterioration of Strategic Road Network in Nepal Based on Different Performance Indicators

<p>Road asset management (RAM) is a systematic process of maintaining, upgrading, and operating physical assets such as roads and bridges in a cost-effective way. The Department of Roads (DOR) is the responsible agency established for the RAM of Strategic Road Network (SRN) in Nepal. Maintenance planning and implementation activities are done by DOR to preserve and maximize the service periods of road assets. The DOR faces the challenge to maintain over 95 percent SRN in fair to good condition. The determination of the rates of deterioration of the road pavements is important for planning the appropriate maintenance approach. However, the pavement condition deterioration curve for SRN in Nepal is not available to forecast future deterioration. Based on the annual road condition survey data, an empirical method developed in the early 2000s is still being used to prepare the integrated annual road maintenance plan. The deterioration process and deterioration rates depend on the pavement’s characteristics, use, and environmental factors. The Markov deterioration hazard model can be applied to estimate and forecast the deterioration process of the pavement. In the model, the deterioration process is described by transition probabilities. The deterioration states are categorized into several ranks based on inspection results and their deterioration rates are estimated by the hazard models. The application of the Markov deterioration hazard model for describing the pavement conditions of SRNs in Nepal using the Surface Distress Index (SDI) and International Roughness Index (IRI) data set from 2014 to 2023 is presented in this paper. For periodic maintenance of road sections in Nepal, only SDI is considered as the prime indicator. In this paper, IRI is discussed as an alternative parameter for making maintenance decisions and prioritizing road sections for periodic maintenance.</p>