Relationship between international roughness index (IRI) and present serviceability index (PSI)

A good road structure may help in reducing the number of accident. Wearing course is the top layer of road structure which is the layer that exposed to the vehicle tires and environment. The International Roughness Index (IRI) and Present Serviceability Index (PSI) are both index that can be used as indicators of road roughness and serviceability. IRI was measured by using the walking profilometer.PSI data was collected manually. Both IRI and PSI was measured along the 100 m section of road. This study only focused on one type of road which was asphaltic pavement located in UTM (University Teknologi Malaysia). The objectives of this study are to determine the IRI, PSI and relationship between IRI and PSI. The statistical analysis which is R2 value was used to evaluate the relationship between IRI and PSI. From this study, it was found that the IRI value increased when the PSI value is decreased. Mostly, the roughness of tested road for this study is unacceptable based on JKR (Jabatan Kerja Raya) Specification. While the PSI rating shows the tested road for this study is still in good condition.