Project Delivery Methods’ Change-Order Types and Magnitudes Experienced in Highway Construction

Abstract

Controlling construction change orders and associated cost growth can be a challenge for highway agencies and is a topic of interest for both practitioners and researchers. Change-order management is particularly crucial on projects using alternative delivery methods with agencies choosing these alternative methods in part to help manage this challenge. Despite the importance, few studies have explored the relationship between change orders and project delivery methods. As such, this study examined the relationships among delivery methods and the types and magnitude of change orders in highway construction. The types of change orders studied are restricted to categories established by the literature and industry. The data set for this study included 162 US highway projects completed between 2004 and 2015. Interviews with agency members working on select projects from the data set were also performed to supplement the quantitative data. The findings reveal that unforeseen condition changes have the most substantial impact on the total cost growth, followed by agency-directed change orders. Agency-directed change orders were found to often add value as a result of owner agencies taking advantage of an initial contract surplus with the greatest benefits realized in design-build delivery. The results of this study provide evidence for agencies and researchers to better understand reasons for change orders across delivery methods and to develop appropriate mitigation strategies.