These sound barriers are mainly used for sound insulation and noise reduction along highways, expressways, elevated composite roads and other noise sources. They can be divided into reflective sound barriers for pure sound insulation and composite sound barriers combining absorption and insulation. The latter is a more effective sound insulation method. It is a wall structure set up on the sides of railways and highways to reduce the impact of driving noise on nearby residents. The soundproof walls are also known as sound barriers. A facility is inserted between the sound source and the receiver to create a significant additional attenuation in the propagation of sound waves, thereby reducing the noise impact within a certain area where the receiver is located. Such a facility is called sound barrier. It can be divided into traffic sound barrier, equipment noise attenuation barrier and industrial boundary sound barrier. On highways and expressways, the sound barriers are mostly used to provide the most effective treatment for sensitive residential areas outside the barriers.