To be effective, how high do soundwalls have to be?

Heights of walls are based upon their ability to lower the level of traffic noise. If a soundwall height is reduced to a point where it no longer achieves this measured noise reduction, it will no longer qualify for federal funding (and it will not be built). An effective soundwall normally blocks the line of sight from a 5-foot-tall receptor to the 11.5-foot truck exhaust stacks on the highway.

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I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.