Evaluation of Effect of Different Types of Asphalt Pavement Distresses on Ride Quality of Road in Terms of International Roughness Index

Road infrastructure and its development is an essential factor for transportation efficiency, economic development, and public safety. Using the International Roughness Index (IRI), this study identifies the influence of various asphalt pavement distresses on ride quality. Primary data for the study were divided into two sections, i.e., IRI data collection through a smartphone based application called ‘RoadRoid’ and distress data collection through visual inspection surveys. The data from a Class I IRI measuring device called ROMDAS Z-250 reference profiler was also collected as the secondary data for the study for validation purpose of RoadRoid. To determine the potential use of IRI as a reliable metric for pavement maintenance decisions and planning in Nepal, a multiple linear regression model was developed to analyze the relationship between various asphalt pavement distresses and IRI. The model revealed a coefficient of determination 0.851. Sensitivity analysis was performed to determine the individual effects of each distress type on ride quality in terms of IRI from which the high severity potholes were found to be the most sensitive one. Additionally, the study also looks at the correlation between IRI and the Surface Distress Index (SDI) to determine how different distresses affect IRI values, which in turn affects ride quality. The coefficient of determination for cubic polynomial relationship was the highest among linear, logarithmic and polynomial relationships with the value of 0.56.