Engineering Guidelines for Highway Noise Shield Design

Federal legislation exists that requires consideration of traffic noise for all Federal Aid Highways. Barriers and liners must be designed primarily as noise reduction structures that must also meet many nonacoustical requirements. In the United States, a few experimental barriers have been installed to date and, although the incidental noise reduction they offer has been measured, not much effort has been made to maximize noise reduction. Several computing programs and nomographs have been developed that provide general siting criteria for barrier placement, but no guidelines exist to achieve the greatest reduction of traffic noise consistent with structural, safety, and esthetic considerations. The comparative merits of various types of barriers are considered and suggestions are offered to improve barrier acoustical performance. Recommendations are suggested to serve as interim guides until more authoritative standards are developed.