How it Helps
To be effective, noise barriers should be constructed high enough to effectively block road noise from traveling a significant distance. Noise walls are generally between 12 and 18 feet high and constructed from brick, concrete, metal, wood, or other materials.4 However, noise barriers can vary widely in their design and construction material.5 For example, past noise barriers often consisted of simple reflective surfaces, but more modern barriers tend to have absorptive surfaces that serve to absorb some of the traffic noise.
Path of Sound:
Prior to constructing noise barriers, engineers should evaluate the many paths that sound can take when encountering a noise barrier.6 For example, noise can either bounce off the wall, be diffracted over the top, or even go through the barrier. Studies that assess the scattering of sound are important to determine how to design noise barriers.
1) Minnesota Department of Transportation (MnDOT) Standalone Noise Barrier Program
MnDOT’s Standalone Noise Barrier Program provides funding for the construction of noise barriers along Minnesota highways to reduce the public’s exposure to traffic noise. MnDOT keeps track of areas where residential noise standards are higher than recommended levels, and cities can submit an application about the area where a barrier is requested.
2) Sound Fighter Systems
Manufacturers such as Sound Fighter Systems provide different types of highway noise barriers for various applications. They offer sound-absorptive barriers that weigh less than traditional concrete barriers and reduce overall traffic noise levels.