Why U.S. Infrastructure Costs So Much

The plan started simply, as many plans do: The Massachusetts Bay Transportation Authority would extend one of its light rail lines from Cambridge to Boston’s northern suburbs. It was estimated to cost less than $500 million when planning began in earnest in 2005. And it would provide transit access to some of the region’s most densely populated neighborhoods that didn’t already have it. 

Then things veered off track. By 2015, state lawmakers temporarily canceled the Green Line Extension (GLX) after costs had ballooned to a staggering $3 billion; progress resumed after an internal audit and management overhaul that reduced the price tag by several hundreds of millions.