This equipment is used for checking and recording the smoothness of profiles of pavements with accuracy and cost-effectiveness. The equipment, developed by Central Road Research Institute, New Delhi (CRRI), comprises of a mobile trussed frame, four datum wheels which provide the plan of reference with respect to which the instrument, moves along the pavement surface during the test. The probing wheel undulates with the surface irregularities and the pen marker linked to probing wheel records the magnitude of the undulation on a graph sheet. The road roughness level is estimated using this equipment.