The Use of International Roughness Index and Structural Number for Rehabilitation and Maintenance Policy of Local Highway

Rehabilitation and maintenance of road performed by technical agencies at the local government in Indonesia, are generally not based on the assessment of road conditions. The value of the structural and functional condition of the pavement is not counted on carefully. As a result, road rehabilitation and maintenance patterns tend to be similar, repetitive and improper. International Roughness Index (IRI) is a parameter for assessing the functional condition of the pavement while the Structural Number (SN) is a parameter for assessing the structural condition of the pavement. Measuring road conditions by using Roadroid applications on smartphones can provide an efficient way, scalable, and low cost to the highway authority to collect road condition data. This study was conducted to determine the conditions of the road both functionally and structurally. Results of research conducted, pavement functionally in a good condition with the acquisition of IRI value of less than 4. Structural pavement conditions indicate that the value of Structural Number Effective (SN_eff) is less than the value of the Structural Number Future (SN_f), thus the structural condition of the road segments has not been able to serve traffic with a design life of 20 years. Prediction of IRI value obtained to determine the type of road maintenance is functionally performed when the value of IRI exceeds the value of 4 with an overlay of material HRS WC 30 mm. Structurally road maintenance carried out various scenarios, the phased construction and direct construction. The type of material and thickness of pavement on a phased construction scenario for the design life of 15-20 years and direct construction gives better results than the phased construction scenarios for the design life of 5-20 years and 10-20 years.