Little research has been carried out on before-and-after studies of traffic and costs in large transport infrastructure projects. The few studies made all show a tendency for forecasts of construction costs to be underestimated, and for traffic forecasts to be overestimated. An examination of...

In terms of risk, many appraisals of very large infrastructure investments assume, or pretend to assume, that infrastructure policies and projects exist in a predictable Newtonian world of cause and effect where things go according to plan. In reality, the world of policy and project preparation...