Stateline.org, a news site that surveys local political stories across the country, picks up the cost overruns story, and, going with the "Big Dig" scenario, adds more meat to Mayor McGinn's case:

With this as a backdrop, the research of Bent Flyvbjerg, a professor at Oxford University in England, has been coming up in Seattle quite a bit lately. Flyvbjerg studied 258 mega-projects around the world, and found that officials underestimated the cost in nine out of 10 cases. On average, tunnel and bridge projects came in 34 percent higher than expected. Flyvbjerg goes so far as to suggest that governments underestimate costs deliberately; if taxpayers knew ahead of time what mega-projects would wind up costing, he says, they’d never approve them in the first place.