However, because of the tremendous amount of land that must be purchased and because in many cases dwellings already border existing roads, creating buffer zones is often not possible. Noise News NPC Resources NPC Home Noise barriers are solid obstruction built between the highway and the homes along the highway. Effective noise barriers can reduce noise levels by 10 to 15 decibels, cutting the loudness of traffic noise in half. Earth berms have a very natural appearance and are usually attractive. However, an earth berm can require quite a lot of land if it is very high.
Walls take less space.
They are usually limited to 25 feet in height because of structural and aesthetic reasons. Noise walls can be built out of wood, stucco, concrete, masonry, metal, and other materials. Many attempts are being made to construct noise barriers that are visually pleasing and that blend in with their surroundings. However, barriers do have limitations. For a noise barrier to work, it must be high enough and long enough to block the view of a road.