Have you ever gotten the impression that there are always huge cost overruns on big infrastructure projects, like high-speed rail lines? If so, you haven’t gotten the wrong impression. That’s the message from Virginia Postrel, writing for Bloomberg News. She quotes a definitive study of cost and ridership estimates by Oxford business school scholar Bent Flyvbjerg, which nails the case.

“It is very common to have cost overruns in big construction projects,” she quotes Flyvbjerg as saying. “It’s the norm. It’s not the exception. ”