via Andrew Sullivan.
Virgina Postrel asks about the reckless lack of accountability in public works projects:
On average, urban and intercity rail projects run over budget by 45 percent, roads by 20 percent, and bridges and tunnels by 34 percent… A charitable explanation is that promoters are starry- eyed and suffer from what psychologists call optimism bias. But it’s suspicious that forecasters rarely seem to learn, even over decades of experience. Alas, contractors, local governments and other advocates have strong incentives to underplay costs and exaggerate benefits to sell their services or attract funding.
I wonder if Len Brown has factored in the 45% over budget the average rail project has managed to achieve with remarkable regularity.
Promoters of rail and toll-road projects also tend to substantially overstate future use, making those projects look more appealing to whoever is footing the bill. Rail projects attract only about half the expected passengers, on average, while in new research still in progress, Flyvbjerg finds that toll roads (including road bridges and tunnels) fall 20 percent short. (Non-toll roads also miss their traffic projections, but their errors go in both directions.)
Rail-ridership predictions are especially over- optimistic in the U.S., where the average gap between expectations and reality is 60 percent, compared with 23 percent in Europe. So a back-of-the-envelope calculation would suggest that California High-Speed Rail can expect to carry only 15.6 million passengers a year by 2035, rather than the 39 million projected.
Sounds familiar doesn’t it? We should be very wary of people suggesting we spend even more of other peoples money to get hugely inflates numbers of other people to take their trains.