Noise barriers as exterior soundproofing

Since the early 1970s, it has become common practice in the United States and other industrialized countries to engineer noise barriers along major highways to protect adjacent residents from intruding roadway noise. The technology exists to predict accurately the optimum geometry for the noise barrier design. Noise barriers may be constructed of wood, masonry, earth or a combination thereof. One of the earliest noise barrier designs was in Arlington, Virginia adjacent to Interstate 66, stemming from interests expressed by the Arlington Coalition on Transportation. Possibly the earliest scientifically designed and published noise barrier construction was in Los Altos, California in 1970. Roadway noise is the collective sound energy emanating from motor vehicles. In the USA it contributes more to environmental noise exposure[1] than any other noise source, and is constituted chiefly of engine, tire, aerodynamic and braking elements. In other Western countries as well as lesser developed countries, roadway noise is expected to contribute a proportionately large share of the total societal noise pollution.Masonry is the building of structures from individual units laid in and bound together by mortar; the term masonry can also refer to the units themselves. The common materials of masonry construction are brick, stone, marble, granite, travertine, limestone, cast stone, concrete block, glass block, stucco, and tile. Masonry is generally a highly durable form of construction. However, the materials used, the quality of the mortar and workmanship, and the pattern in which

he units are assembled can significantly affect the durability of the overall masonry construction.The Arlington Coalition on Transportation (ACT) is a citizens group formed to oppose the construction of Interstate 66 through Arlington, Virginia. The focal activity of ACT was the conduct of a lawsuit filed against the Virginia Department of Transportation in 1971 in district court. This small citizen's group, founded by Jim and Emelia Govan, actually defeated the powerful Virginia Highway Commission, as the agency was then known. After considerable further legal and technical struggles, a compromise solution was reached to create a scaled down highway segment, including a transit element. Los Altos i/ls lto?s/ is a city at the southern end of the San Francisco Peninsula, in the San Francisco Bay Area. The city is in Santa Clara County, California, United States. The population was 28,976 according to the 2010 census. Most of the city's growth occurred between 1950 and 1980. Originally an agricultural town with many summer cottages and apricot orchards, Los Altos is now an affluent bedroom community. Los Altos has several distinctive features. Commercial zones are strictly limited to the downtown area and small shopping and office parks lining Foothill Expressway and El Camino Real. Forbes places Los Altos (area code 94022 and 94024) as the 24th most expensive ZIP code in the United States, behind such cities as Alpine, NJ, Atherton, CA, and Beverly Hills. This lists median home price as over $2,500,000.[4] Los Altos means "the heights" or "foothill" in Spanish.