Noise barriers are solid obstructions built between the highway/railway and city areas, designed to reduce the noise of traffic.
They are built only after noise impact studies are conducted and certain conditions are met. Noise barriers can be formed from earth mounds along the road or from high, vertical walls. Noise walls built of concrete, masonry, metal, wood and other materials take less space than earth berms.
Increasingly, attempts are being made to construct noise barriers that are visually pleasing and that blend in with their surroundings.
Several options are available. For new roads engineers will try to reduce the anticipated noise while they are designing the road by shifting the road away from the affected properties.
The next step is to consider noise reducing devices. The effectiveness of a noise wall and an earth berm of equivalent height are broadly similar. The use of an earth berm is not always an option, due to the excessive space they require. Walls are an effective mitigation measure which can reduce traffic noise significantly and improve quality of life for people living behind them.