🤖 AI Summary
This study addresses the pervasive issue of horizontal change orders (COs) under the Design–Bid–Build (DBB) delivery method, which frequently trigger cost overruns and schedule delays. Leveraging historical data from 770 Florida Department of Transportation projects (581 unit-price and 189 lump-sum contracts), a discrete choice model is developed to quantitatively identify key determinants of CO frequency—including project size, duration, and work type—and to assess the differential impact of contract type on CO incidence. Its novelty lies in the first application of discrete choice modeling to inform DBB contract-type selection, moving beyond heuristic, experience-based matching. Empirical validation demonstrates that the model outperforms current practice, yielding higher accuracy in contract-type recommendation and improved precision in CO frequency prediction. The framework thus provides a practical, quantitative decision-support tool for transportation agencies to optimize procurement strategies and mitigate change-order risk.
📝 Abstract
Change orders (COs) are a common occurrence in construction projects, leading to increased costs and extended durations. Design-Bid-Build (DBB) projects, favored by state transportation agencies (STAs), often experience a higher frequency of COs compared to other project delivery methods. This study aims to identify areas of improvement to reduce CO frequency in DBB projects through a quantitative analysis. Historical bidding data from the Florida Department of Transportation (FDOT) was utilized to evaluate five factors, contracting technique, project location, type of work, project size, and duration, on specific horizontal construction projects. Two DBB contracting techniques, Unit Price (UP) and Lump Sum (LS), were evaluated using a discrete choice model. The analysis of 581 UP and 189 LS projects revealed that project size, duration, and type of work had a statistically significant influence on the frequency of change orders at a 95% confidence level. The discrete choice model showed significant improvement in identifying the appropriate contract type for a specific project compared to traditional methods used by STAs. By evaluating the contracting technique instead of project delivery methods for horizontal construction projects, the use of DBB can be enhanced, leading to reduced change orders for STAs.