Beyond the narrative of failure: Road project cost overruns are manageable

Cost overruns in road transport projects have long been portrayed as inevitable. They were typically measured as the percentage difference between actual and estimated costs at the time of decision-to-build, expressed relative to the estimated cost. Influential studies, notably Flyvbjerg et al. (2002), popularized the view that projects almost always overrun and by large margins. Yet recent evidence tells a different story. Norwegian studies show that overruns have been low and stable over time and declined further after governance reforms such as the Quality Assurance scheme. Much of the escalation occurs during front-end planning, while estimates at decision-to-build are generally accurate. Similar patterns appear elsewhere. New measurement approaches reveal that earlier studies in England and Sweden overstated overruns. In Sweden, estimates stabilize once construction begins. Swiss highway projects show median overruns of around 5%, and Australian and New Zealand studies also find modest medians once outliers are accounted for. Other research highlights the role of reforms in planning, assurance, procurement, and accountability in improving delivery. This essay argues that overruns are not destiny. With the right governance and institutional reforms, governments can act to improve cost performance in road projects. Early studies relied on measurement that overstated central tendencies. Whereas we reflect on the wider and supportive international literature, we focus more on evidence from the Norwegian context.