Looking at What Is Driving Up the Cost of Highway Construction.

The cost of building one mile of interstate highway in the 1980s was three times what it cost in the 1960s, adjusted for inflation, according to "What Is Driving Up the Cost of Highway Construction?" a paper from Brookings. The increase isn't because highway planners left the most geographically challenging routes to do last, or because of changing costs (for construction material or labor, of acquiring rights of way or the costs of planning, or large changes in federal interstate highway construction standards over time)--all common explanations.

Instead, the paper suggests two other explanations. One is what the authors call "the rise of 'citizen voice'" beginning in the 1970s, which brought costly environmental review delays. "Projects associated with wigglier highways may have encountered resistance that both led to less direct routes and also more expensive construction"--a 0.01 mile per year increase in the wiggliness of a highway is associated with a $9.71 million increase in costs...