The adverse effects of traffic noise are a serious concern both domestically and internationally. In many urban places, highways have been lined with noise barriers on one or both sides in an effort to reduce the noise levels alongside the highway.
Barriers are sometimes effective, often disliked and always expensive.
Much effort has been spent toward modeling highway noise and noise reduction by barriers. In particular, accurately modeling the sound field outside of parallel noise barriers has proved to be a challenge. An alternative to protection by barriers is noise reduction at the source. For modern highway vehicles, the major component of traffic noise comes from tire-pavement interaction, which produces noise by several mechanisms. How much noise these mechanisms produce is greatly affected by tire and pavement design.