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 in noise level. This occurs because the wall has already intercepted a high percentage of noise energy.
