Equipment for Measurement of Road Surface Roughness as Applied to Rumble Strip Evaluation

Equipment for evaluating the relative roughness (or smoothness) of a road surface is described. Although the equipment was developed primarily for investigation of various types and patterns of rumble strips for traffic control, it could also be applied to the evaluation of street or highway pavement conditions. The equipment measures the vertical movement of the rear axle of the test vehicle with respect to the frame of the vehicle in 0.125-in increments. Each increment of movement is converted into an electrical pulse. The pulses are accumulated with an electronic counter throughout a test run with the vehicle. The magnitude of the resulting total count is an indication of the relative roughness of the tested surface.