Noise barrier walls

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Noise barriers are solid obstructions built between the highway and the homes along the highway designed to reduce the loudness of traffic. Barriers can be formed from earth mounds along the road, usually called earth berms, or from high, vertical walls.

Concrete noise barriers take less space and require little to no maintenance.

Noise walls built of wood, stucco, concrete, masonry, metal, and other materials take less space than earth berms. Many attempts are being made to construct noise barriers that are visually pleasing and that blend in with their surroundings.

Noise Barrier Terms

Benefited Properties
A property that is not affected by a construction project but benefits anyway from a noise abatement system prescribed for impacted properties. For a property to have this distinction, the noise barrier must provide at least five decibels of noise reduction.

Impacted Properties
A property whose noise level is predicted to exceed criteria identified in federal and state policy. A property is said to be impacted if it meets either of the following criteria:

• The projected noise level approaches or exceeds the level recommended by the Federal Highway Administration (FHWA), using the noise abatement criteria table.
• The projected noise level represents a substantial increase over the current noise level.

Protected Properities
A property is considered to be protected by a noise barrier if:

• It is impacted and receives a noise level reduction of at least five decibles.

-or-

• Has benefited in that it was not impacted but still receives a reduction in noise level.

Substantial Increase
If a property's existing noise level is predicted to increase by 10 decibels or more as a result of a proposed road project, the increase is considered substantial and therefore the property is impacted.

Noise Barrier Facts

• Substantially reduce noise levels for people living next to highways
• Reduce the loudness of traffic noise by as much as half
• Be effective, regardless of the material used

Noise barriers are:

• Most effective within 61 meters (200 feet) of a highway (usually the first row of homes)

Noise barriers must be:

• Visually appealing
• Designed to preserve aesthetic values and scenic vistas

• Completely block all traffic noise

For More Information

• Noise Barrier Walls  (FHWA Web site)
• Vehicle emission levels (FHWA Web site)
• Compatible growth and development (FHWA Web site)