Would a berm be as effective as a noise wall in reducing noise levels?
Earth berms are just as effective as noise walls. Studies have shown that earth berms actually reduce noise levels to a greater extent than noise walls due to absorption and edge effects. However, the use of berms depends on the space available. For maintenance reasons, IDOT requires at least a 3:1 slope on berms. For example a 12-foot berm with a 3:1 slope would be approximately 72 feet wide at the base. The available area for abatement would need to accommodate this base width. Why can’t we build a taller wall to get greater noise reduction? The barrier height is just one element that affects the traffic noise reduction achieved. A noise wall that breaks the line of sight between the traffic noise source and noise receiver reduces traffic noise up to 5 dBA. Each additional two feet of noise wall improves the traffic noise reduction by approximately 1 dBA; however, there are diminishing returns. Beyond a certain height, incremental changes in height do not provide additional reduction
Related Questions
- How will the proposed test noise wall impact the construction? If the test wall is effective, will INDOT create a policy on when they will be used?
- How much will the noise levels change after a noise wall has been built and will the change be noticeable?
- Would a berm be as effective as a noise wall in reducing noise levels?
