A Study on the Road Conditions Assessment Obtained from International Roughness Index (IRI): Roughometer Vs Hawkeye

Abstract

Study is aimed to find out what is the representation of IRI (International Roughness Index) from the Roughometer results if it was used as substitute of IRI from the Hawkeye results on the road conditions assessment, which is the hawkeye device is included in the Class I category of roughness measurement devices, while the Roughometer is in the Class III. The Student’s t statistical operation is used to find the representation of IRI from the Roughometer results as substitute of IRI from the Hawkeye results. It is determined by analyzing the comparison of the mean values of both measurement results. The study was conducted on three national road sections in North Sumatra Province, namely: Bts. Kota Binjai – Bts. Kota Medan road with a length of 7,300 meters, Bts. Kota Tebing Tinggi – Bts. Kabupaten Simalungun road with a length of 18,800 meters, and Bts. Kabupaten Simalungun/Bts. Kabupaten Sergai road with a length of 15,000 meters. The IRI values were measured by using Roughometer and Hawkeye devices. The measurements were carried out with the survey team from the Center for Implementation of the National Road II Medan, which was also the facilitators in providing the survey equipment, Roughometer and Hawkeye. The statistical test results that the IRI values from the Roughometer measurement results were significantly different from the IRI values from the Hawkeye measurement results (Ho was rejected) because the Student’s t-test results for the three road sections showed that tcount > tcritical and p-value < 0.05. And the assessment of the road functional conditions using Roughometer showed the same results on one road section but worse results on the other two road sections compared to assessment of the functional conditions with Hawkeye. Based on the analysis results, it can be concluded that the IRI values from Roughometer were more conservative in representing the functional conditions of the road when used as a substitute for the IRI values from Hawkeye.