Noise barrier ,also called a soundwall, sound berm, sound barrier, or acoustical barrier), is an exterior structure designed to protect inhabitants of sensitive land use areas from noise pollution. Noise barriers are the most effective method of mitigating roadway, railway, and industrial noise sources - other than cessation of the source activity or use of source controls.

The acoustical science of noise barrier design is based upon treating an airway or railway as a line source. The theory is based upon blockage of sound ray travel toward a particular receptor; however, diffraction of sound must be addressed. Sound waves bend (downward) when they pass an edge, such as the apex of a noise barrier. Further complicating matters is the phenomenon of refraction, the bending of sound rays in the presence of an inhomogeneous atmosphere. Wind shear and thermocline produce such inhomogeneities.
 

Noise Barriers has many kind of types and styles as per the materials, outside shape, and application area.

1. Noise barrier types as per material
    Metal louvers noise barrier
    Metal microporous noise barrier
    Color plate noise barrier
    Fiberglass noise barrier
    Combination transparent noise barrier

2. Noise barrier types as per outside shape
    Arc-shaped noise barrier
    Top arc noise barrier
    Bending on the top noise barrier
    Upright noise barrier

3. Noise barrier types as per application area
    Viaduct noise barrier
    Highway noise barrier
     Railway/High-speed rail noise barrier
     Residential area/plant noise barrier
     Cooling tower of power plant noise barrier
     Air conditioning unit noise barrier