Geotechnical characterization of cost overrun drivers in highway projects: Predicated on heterogeneous ground conditions in the Niger delta region of Nigeria

Literature analysing cost overruns in highway projects abound the literature: most espouse that Infrastructure clients face significantly higher levels of cost overrun than those experienced by other construction industry sectors. The consequences of cost overruns in highway projects has led some to question the efficiency of public highway commissioners through the developed and developing world, leading to questions about the ability of such organisations to initiate and deliver highway infrastructure projects. An expansive range of research identifying theoretical and technical explanations for this negative trend has emerged from academe,  resulting in the emergence of three distinct schools of thought. The first suggests   reliant on heuristics and optimism bias is responsible for poor accuracy levels. The second espouses that inaccuracy stems from deliberate deception by clients and their professional advisors due to corruption or politically induced malpractice. Whereas the final school suggest technical explanations, most likely resulting from 'Latent Pathogens', which often lay dormant in the complex interactive processes of infrastructure projects are unintentionally triggered and lead to a series of events culminating in a cost overrun.  In an attempt to better understand the impact of latent pathogens on the accuracy of project estimates in the Niger Delta, longitudinal cost data gathered from 61 completed highway infrastructure projects has been comprehensively analysed,.  The results identify that latent pathogens such as heterogeneous ground conditions, account for the majority of the recorded variance between the initial estimates and the project’s final account.