There Have Been Studies

I have notice that I have gotten a lot of "There have been extensive studies" as an explaination for something totally stupid, and said by someone who is put out front, but has no real authority. For example, the state government gave lots of money for a sound wall to be built in my neighborhood to reduce noise from a new parkway they ran though my 'hood. The sound wall was built for cars, not trucks. So the state let trucks go on the parkway, and we can see the tops of trucks and their exhaust pipes over the sound wall. We can hear the trucks and exhaust and horns over the sound wall, and it is so loud that you cannot carry on a conversation outside. The explaination I got from the government lowly worker was, "There have been extensive studies done, and you should have an effective sound wall." OK, where is the study, and can I read it? And by the way, can I add empirical data of TOO MUCH NOISE to that study?