Abstract
The study considered four basic highway noise reduction constructions: (1) roadside barriers, (2) elevated highway sections, (3) depressed highway sections, and (4) roadside structures. To minimize the number of variables to be evaluated, strict criteria were imposed on the selection of the test sites. For each selected test site, a comprehensive measurement plan was developed. The measurement program was designed to fully describe the acoustic characteristics of each site, and to assess the contribution of traffic and environmental parameters to the-all noise reduction characteristics of each highway geometry.