UL Lafayette: CDW: I-49 Connector: Noise Barriers

				I-49 Connector: Sound Study


				BACK \| NEXT TOPICS introduction public process case studies alignments garden urbanism alt. street links public realm neighborhoods lighting sound study public art conclusion recognition SUB-TOPICS introduction land use reducing noise noise barriers	Noise Barriers

					Finally, noise barriers can be erected between noise sources and noise-sensitive areas. Noise barriers are solid obstructions built between the highway. Effective noise barriers can reduce noise levels by 10 to 15 dBA, cutting the loudness of traffic noise in half. These barriers may take the form of berms made of sloping mounds of earth or walls and fences. Earth berms have a very natural appearance and are usually attractive, but can require a lot of land if they are high, Noise walls take less space and can be built from a range of material that are visually pleasing and blend with their surroundings. The FHWA also has barrier design guidance, which is used to size and locate the noise walls. Noise walls are most effective for noise-affected sites within approximately 200 feet of the highway. the barrier length should be at least eight times the distance from the barrier to the affected site. For example, a home approximately 50 feet from the noise wall would require a sound wall at least 400 feet in length. Openings in noise walls for driveway connections or intersecting streets destroy the effectiveness of barriers. For the I-49 Connector Project, this eliminates the option of placing the noise walls at ground level and requires that they be at the interstate height to reduce noise transmission effectively. The noise walls of I-49 through Shreveport are perforated metal, with an acoustic core and rigid metal backing that comes in a range of colors. This is mounted directly to the elevated interstate to provide noise reduction. Noise reduction goals for noise walls influence acoustical considerations and, in conjunction with non-acoustical considerations such as maintenance, safety, aesthetics, physical construction, cost, and community participation, determine various barrier design options. Lafayette may take the opportunity to introduce symbols of local or regional identity to the walls in terms of aesthetics, relying on such things as materials, form, surface treatment, and color- even murals and signage Traffic noise mitigation for the I-49 Connector will require no single measure, but a range of measures both administrative and physical, to minimize noise impacts. The options recommended for the sites that border the proposed highway include a Noise Impact Overlay Zone, acoustical site planning, acoustical architectural design, acoustical construction, and construction of noise barriers.






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Document last revised Thursday, April 22, 2004 10:46 AM