Evaluation of Pavement Roughness Using Smartphones

A well-maintained pavement network is an essential component of good road infrastructure. Roughness is an important indicator of the condition and riding quality of pavement and influences vehicle operation costs. Pavement roughness is indicated by a dimensionless index called IRI (International roughness index), which is the cumulative displacement per unit length. Bump Integrator, ROMDAS (Road Measurement Data Acquisition System) equipment are widely used to measure the IRI. This study aims to utilize the potential of smartphones equipped with sensors like accelerometer which collect the acceleration data leading to a cheaper alternative to compute pavement roughness. Roughness data was collected on the State Highway using different smartphones and vehicle types at varying speeds. The data obtained was validated using data obtained from ROMDAS. The R2 value between the smartphone-based roughness index and the roughness index obtained from ROMDAS data was found to be in the range of 0.83 to 0.93 for a vehicle speed of 40kmph, which decreased with an increase in speed. IRI obtained from smartphone placed on a two-wheeler at 40kmph was found to have R2 value of 0.78 which was lower than that of the four-wheelers. It was inferred from the study that IRI obtained was not only influenced by the vehicle type and speed but also by the smartphone hardware and performance. IRI values do not vary much with different cars given that the suspension is in good condition.