The purpose of this paper is to compare and assess the measured and calculated attenuations obtained from earthen sound berms and also to assess the perceived effects of selected berms on adjacent residential neighborhoods by means of an attitudinal survey. Simultaneous sound readings were taken before and after construction of the berms. It was found that they produced median sound-level attenuations of 5 dB (A) at the right-of-way line and 3 dB (A) at a distance corresponding to the front sidewalk of the homes along the freeway. The attitudinal survey, conducted before and after the construction of sound berms, indicated that residents immediately adjacent to the freeway perceived a reduction in sound levels and increased privacy both indoors and outdoors. The study concluded that even minor attenuations of freeway noise of 5 dB (A) or less are discernible within adjacent neighborhoods and, based on the subjective responses of the attitudinal survey, are per· ceived to be greater than actually measured. Also, the increased privacy afforded by sound berms should be a consideration in the evaluation of proposals for the construction of future sound-attenuating devices.

In the fall of 1971 the Milwaukee metropolitan distrir. t office of the Wisconsin Division of Highways undertook a series of safety improvement projects, particularly concrete median barriers, on the interstate freeways within its jurisdiction. During the design of these barriers it became evident that there would be an excessive