Noise Barrier (also known as Noise Walls, Acoustic Barriers, Noise Fences or Sound Barrier Walls) have been made of a number of different materials over the years. Noise barriers are solid obstructions built between noise sources, be it highway noise or air conditioning equipment,that are designed to be ¡°line of sight¡± interruptions between the noise source and the receiver. Noise Barriers are typically made from concrete, steel, vinyl, wood or earth mounds called ¡®berms¡¯. Berms are pretty good but in order to get them high enough to be effective sound barriers, they have to be so wide they take up huge amounts of valuable land. Steel barriers are expensive, subject to corrosion and dent badly especially if they are going to have snow thrown up against them by snow plows. Concrete noise barriers are incredibly heavy, very expensive and are subject to needing replacement in as little as 10-20 years. Properly engineered vinyl barrier Like Silent Protector Noise Wall, is the best choice for lower in place costs, great acoustic performance and appearance combined with a life span many times that of all other acoustic barrier noise wall systems. There are a variety of types of noise barriers that are regularly used to reduce noise pollution. Noise barriers are any outside structure that are used to block sound waves from roads, railroad tracks and industrial areas. They can be made of natural or manmade materials. To be effective, these barriers must take a variety of factors into consideration. When engineers are designing noise barriers, they look at the amount of traffic on a road, the way that the road is shaped, how the land lies around the roadway and what type of materials the road is made from. Noise barriers are expensive to build and install. In particular, barrier walls that run alongside interstate highways can mean miles of construction. For this reason, noise barriers are most often constructed in areas where the roadways pass through residential areas.