Challenges for Tire Noise Evaluation on Common Pavements

Developing common methods of noise evaluation and facilities can present a number of challenges in the area of tire/pavement noise. Some of the issues involved include the design and construction of pavements globally, the change in pavement over time, and variation in the noise produced with standard test tires used as references. To help understand and address these issues for airborne tire/pavement noise, acoustic intensity measurement methods based on the On-board Sound Intensity (OBSI) technique have been used. Initial evaluations have included measurements conducted at several different proving grounds. Also included were measurements taken on a 3m diameter tire noise dynamometer with surfaces replicating test track pavements. Variation between facilities appears to be a function of both design/construction and pavement age. Consistent with trends in the literature, for smooth asphalt surfaces, the newest surface produced levels lower than older surfaces. For more aggressive, exposed aggregate concrete surfaces, the levels produced appear to depend more on the roughness built into the surface rather than aging effects. The tire noise dynamometer produced overall levels slightly higher than the actual pavements especially at higher frequencies. The long term stability and durability of the dynamometer surface make it a useful reference for evaluating the actual pavements over time.