  Lock-in, the escalating commitment of decision-makers to an ineffective
course of action, has the potential to explain the large cost overruns in large
scale transportation infrastructure projects. Lock-in can occur both at the
decision-making level (before the decision to build) and at the project level
(after the decision to build) and can influence the extent of overruns in two
ways. The first involves the methodology of calculating cost overruns according
to the formal decision to build. Due to lock-in, however, the real decision to
build is made much earlier in the decision-making process and the costs
estimated at that stage are often much lower than those that are estimated at a
later stage in the decision-making process, thus increasing cost overruns. The
second way that lock-in can affect cost overruns is through practice. Although
decisions about the project (design and implementation) need to be made,
lock-in can lead to inefficient decisions that involve higher costs. Sunk costs
(in terms of both time and money), the need for justification, escalating
commitment, and inflexibility and the closure of alternatives are indicators of
lock-in. In this paper, two case studies, of the Betuweroute and the HSL-South
projects in the Netherlands, demonstrate the presence of lock-in and its
influence on the extent of cost overruns at both the decision-making and
project levels. This suggests that recognition of lock-in as an explanation for
cost overruns significantly contributes to the understanding of the inadequate
planning process of projects and allows development of more appropriate means.
