Model development of road performance indicator-related travel time using international roughness index: A case study national road network of Sulawesi

Abstract

The International Roughness Index (IRI) is widespread in measuring road performance. However, travel time is a more critical benchmark in measuring road performance and the transportation system's performance. Therefore, new studies and models are needed to determine the relationship between IRI and travel time to obtain a segment performance function model influenced by road conditions. The study begins with a traffic condition survey to obtain vehicle travel time data on various road conditions. Assessment of road conditions uses the value of road surface flatness obtained from the results of Hawkeye measurements by carrying out actual travel throughout the national road network of Sulawesi Island. The study results show that the IRI value greatly influences the achievement of travel time as a road performance indicator in Indonesia. The equation of the relationship function of the vehicle travel time in free flow with the value of the flatness of the road surface is y=−6,062x2 +1,068x−1,0873 with R2 0,9314. At the same time, the equation of travel time as a function of road performance is ta = α1 (v/c)β + α1 (v/c) - 6,062x2 + 1,068x - 1,0873.