  Smartphones are equipped with sensors such as accelerometers, gyroscope, and
GPS in one cost-effective device with an acceptable level of accuracy. There
have been some research studies carried out in terms of using smartphones to
measure the pavement roughness. However, a little attention has been paid to
investigate the validity of the measured pavement roughness by smartphones via
other subjective methods such as the user opinion. This paper aims at
calculating the pavement roughness data with a smartphone using its embedded
sensors and investigating its correlation with a user opinion about the ride
quality. In addition, the applicability of using smartphones to assess the
pavement surface distresses is examined. Furthermore, to validate the
smartphone sensor outputs objectively, the Road Surface Profiler is applied.
Finally, a good roughness model is developed which demonstrates an acceptable
level of correlation between the pavement roughness measured by smartphones and
the ride quality rated by users.
