The 'Dark Side' Of Transit Forecasting

Half of traffic forecasts are off by at least 20%, according to a study of 210 international road and rail projects.

"Analysis of traffic forecasts and actual first year traffic at 210 international road and rail projects concludes that the road forecasts are inaccurate with about half out by over 20%, but not seriously biased up or down. Transit ridership forecasts, by contrast, are grossly inaccurate, heavily biased upward, and clearly manipulated by special interests. The average error of transit ridership is +106%. Recent projects show no improvement over earlier ones.

Very often planners are a large part of the problem however, FHB write. Accurate forecasts do not serve their purposes because they are more interested in using numbers to promote the project, what FHB call the "dark side" of forecasting.

'Forecasting is here mainly another kind of rent-seeking behavior, resulting in a make-believe world of misrepresentation that makes it extremely difficult to decide which projects deserve undertaking and which do not.' "

Thanks to Chris Steins

Full Story: Forecasts shoddy for roads, mendacious for transit - Flyvbjerg

Comments

Prepare for the AICP* Exam

Join the thousands of students who have utilized the Planetizen AICP* Exam Preparation Class to prepare for the American Planning Association's AICP* exam.
Starting at $245
AICP CTP Storefont Display

The first online AICP* CTP exam prep class

Are you ready to take the AICP* Certified Transportation Planner exam?
Priced at $245 for May exam!
Book cover of Unsprawl

Unsprawl: Remixing Spaces as Places

Explore visionary, controversial and ultimately successful strategies for building people-centered places.
Starting at $12.95
Book cover of Where Things Are from Near to Far

Where Things Are From Near to Far

This engaging children's book about planning illustrates that "every building has its place."
$19.95