Noise mitigation strategies involving both noise reduction at the source of transportation noise and at the receiver of transportation noise are reviewed. The following major sources of noise within a motor vehicle were considered: engine, intake, exhaust, cooling fan, transmission, and tire noise. Current research intended to address methods of reducing noise for each of these sources is discussed. It was found that vehicle manufacturer efforts in the U.S. to reduce vehicle noise is currently being motivated by marketplace demands for quiet vehicles. In addition to the potential noise reduction from specific components of the vehicle, it was found that the type of roadway pavement can have a significant effect on tire/road noise.
A key strategy for reducing transportation noise at the receiver of the noise is land use compatibility planning. Local agencies who have successfully implemented noise and land use compatibility planning programs were interviewed. These programs fall into two broad categories. The first category is land use compatibility brought about by zoning. In this category, land uses that are inherently compatible with transportation noise sources are located adjacent to the sources. The second category, referred to as proponent mitigated development, involves a process of mitigation needed to make the land use compatible with transportation noise through mitigation efforts funded by the proponent of the development. It was found that noise and land use compatibility programs were most beneficial to communities in the earlier stages of development whereas the use of a local noise ordinance was found to be more beneficial to communities that are more fully developed.