Pass-by noise: regulation and measurement

Traffic noise is generated by four subsources of a highway vehicle: engine/powertrain noise, intake and exhaust noise, aerodynamic noise, and tire/road noise. For a normally maintained highway vehicle, the tire/road noise is a dominant subsource at speeds higher than 80 km/h. The road surfaces that produce less tire/road noise are an important strategic solution to address the future highway vehicle noise problems. This chapter studies general vehicle pass-by noise with a focus on generation mechanisms, characteristics, and frequency components of the pass-by tire/road noise, as the pass-by tire/road noise is one of the important components of the general vehicle pass-by noise. The pass-by noise contributed from each of the main subsources will be separately discussed for their frequency contents and characteristics. This chapter aims to summarize the state of knowledge of the pass-by noise, to define terminology, and to connect different disciplines for studying the vehicle pass-by noise and its test, analysis, and simulation methods.