Improving cost performance in design-bid-build road projects by mapping the reasons for cost overruns into the project phases

Design-Build (DB) is an alternative project delivery system that has shown to be better in controlling cost growth than the traditional Design-Bid-Build (DBB) system. However, some road administrations are not legally allowed to implement DB and keep using DBB with consequent disadvantages, such as having high-cost overruns. There is a need, therefore, to provide road administrators delivering DBB projects with research-based mitigation measures that can help them to minimize the main reason for cost overruns. To this end, this study identifies the main reasons for cost overruns in the design, the procurement and the construction phases of DBB road projects and point out to the specific elements of DB project delivery that might help to minimize these reasons. To identify the reasons, an exploratory content analysis was performed on interviews conducted with 41 professionals involved in road project management in Chile. Literature review and document analysis of DB were used to analyze the identified reasons under the framework of the DB practice in the United States. The results showed that four elements based on the DB approach might be used to minimize cost overruns in DBB projects: (1) in the design phase, road administrators should consider the early integration of the constructor&rsquo;s expertise. In the procurement phase, they should establish (2) instances for effective information exchange and (3) a goal-oriented selection process. Overall, road administrators should consider (4) establishing a one-point of high-level accountability for the design, the procurement, and the construction phases. This study will serve DBB road administrators to start the transition from DBB to more collaborative approaches that will help to minimizer cost overruns and, therefore, to improve the project cost performance.</p