The Federal Highway Administration says most highway sound barriers are constructed of concrete or masonry block, range from 3-5 meters [9-16 feet] in height, and cost between $175 and $200 a square meter.There is little shame in running half a decade behind parapundit, I suppose.
According to the American Association of State Highway and Transportation Officials, there are "more than 2,630 linear miles of sound barriers" along U.S. highways, constructed at a cost of some $1.4 billion.
By comparison, the Pentagon is spending about $3.9 billion a month in Iraq and Afghanistan, not counting rebuilding costs, the Associated Press has reported.
I was in Minneapolis last week and was treated to miles and miles of aesthetically-pleasing highway sound barriers along I-35 and I-90. Over the last few years, I've noticed them in several cities I've travelled to. They began going up along the I-435 loop of my native stomping grounds four or five years ago. If you're unfamiliar with them, take a look at these google images.
Municipalities are putting up hundreds of miles of these walls all across the country--and justifying the costs that accompany it--just to keep noise out. These structures could just as well be used to keep people out. A couple hundred miles here, a couple hundred miles there, and before long we're talking about real mileage--say, around 2,000. Anyone who claims that building a wall along the entire US-Mexico border is an impossible undertaking is telling a lie.