Pavement Macrotexture Monitoring through Sound Generated by a Tire-Pavement Interaction

Abstract

A road is considered safe when it provides adequate friction between the tire and pavement surface interaction to avoid accidents. The current manual methods of evaluating surface friction of roads are not only dangerous for the inspectors and motorists on the road but are very time-consuming and subject to the inspector’s judgment. This paper confirms the possibility of monitoring pavement macrotexture from acoustic measurements underneath the body of a moving vehicle. Currently, macrotexture is quantified by a mean texture depth (MTD) index. In the present work, MTD is estimated from the sound generated by the tire-pavement interaction in a moving vehicle. To establish this approach, experiments were performed at the National Center for Asphalt Technology (NCAT), Auburn, Alabama. Signal processing techniques were used to identify a frequency band that led to an accurate correlation between integrated acoustic pressure and MTD collected by NCAT. This frequency band depends on the speed of the vehicle. The effect of microphone locations and the speed of the vehicle on macrotexture monitoring are studied, and conclusions are presented. Microphones that are close and oriented toward the contact patch of the rear tire have the highest correlation to MTD. It is observed that raising the microphones by 33 cm decreased the correlation by ∼13%. It was shown that higher vehicle speed has higher correlation values. Accurate estimates of MTD were obtained for road surfaces having MTD values in the range of 0.5–2.5 mm, with vehicle speeds in the range of 32–80 km/h (20–50 mi/h).