Highway noise will be discussed from the standpoint of planning and designing highways as well as the corresponding questions of land use in the adjacent corridor. In the location decision of a highway corridor and in choosing the specific highway alignment, the noise impact upon the adjacent community can be evaluated by predictive methods and compared to existing noise levels in that corridor. In such a way, one can compare the noise impacts of alternate location or alignment decisions in a manner consistent with applicable federal and state noise criteria. Once an alignment determination has been made the detailed design of the roadway including roadway elevation and the traffic operating characteristics can be addressed such that noise is minimized in the adjacent community. Factors by which highway noise may be further minimized by land use planning and proper design and construction of buildings near the highway itself will also be discussed.
Sound propagation near an urban highway is an extremely complex matter because of the role which meteorological conditions play as well as the role of complex topography and the existence of man made structures. The technology for addressing the variety of these features by means of a computer model will be discussed, especially as this prediction method allows one to take into account future descriptions of highway traffic which can address traffic volumes, vehicle mix, vehicle speeds, future noise control devices at the vehicular source and other factors.