Noise walls are free-standing barriers built parallel to a highway. They are usually found near public areas, such as parks, and residential areas. The walls range in height from 6 to 20 feet, but are normally 12 to 15 feet tall. They can reduce noise levels by 10 to 15 decibels, cutting the loudness of traffic noise in half. Barriers can be formed from earth berms, or constructed of wood, stucco, concrete, masonry, metal, or other materials. This feature class contains Type I and Type II noise walls that have been constructed. This data has been synchronized with the LRS dated December 31, 2018. Data appended April 2022