Little research has been carried out on before-and-after studies of traffic and construction
costs in large transportation infrastructure projects. The few studies that do exist show that
forecasts of construction costs tend to be underestimated and those of traffic, overestimated.
An examination of construction costs and traffic in seven large Danish bridge and tunnel
projects indicates that, on average, construction costs were underestimated and traffic was
overestimated in the initial phases of planning. This pattern is also found for similar projects …

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 construction costs and traffic in seven large Danish bridge and tunnel
projects shows that construction costs have been underestimated and traffic has been
overestimated in the initial phases of planning. This pattern is also found in studies from …