The infrastructure industry has witnessed significant changes in project delivery methods over the past few decades. Traditional design-bid-build models have given way to alternative delivery (AD) approaches, which offer faster project completion and greater flexibility. This shift has been driven by the need for performance-based requirements and innovative contracting strategies. Today, three primary AD models dominate the construction sector: Construction Manager at Risk (CMAR), Design-Build (DB), and Progressive Design-Build (PDB). Each model brings unique advantages and challenges, influencing how projects are procured and executed.

Understanding Modern Project Delivery Methods

In recent years, traditional procurement methods have evolved to accommodate more flexible and efficient project delivery systems. The emergence of Construction Manager at Risk (CMAR) represents a significant departure from conventional practices. In this model, the owner contracts separately with a design consultant and a construction manager who collaborates closely throughout the project lifecycle. This approach offers cost certainty through a guaranteed maximum price but requires specialized contractor expertise, which can limit its applicability. CMAR has gained popularity due to its ability to streamline processes and reduce risks for owners.

One of the key features of CMAR is the early involvement of the construction manager, who provides valuable input during the design phase. This collaboration ensures that potential issues are identified and addressed before construction begins, leading to smoother project execution. However, finding contractors with the necessary skills and experience can be challenging, especially in regions where such expertise is limited. Despite these constraints, CMAR has proven effective in various large-scale infrastructure projects, demonstrating its value in delivering complex initiatives within budget and schedule constraints.

Evaluating Design-Build and Progressive Design-Build Approaches

Beyond CMAR, two other prominent AD models have emerged: Design-Build (DB) and Progressive Design-Build (PDB). Both methods prioritize speed and efficiency while offering distinct benefits. DB allows owners to select a single entity responsible for both design and construction based on a best-value proposal. This integrated approach minimizes interfaces between parties and shifts most of the risk onto the design-builder. However, it often results in higher initial costs for owners as the contractor assumes full responsibility for delivering the project within agreed parameters.

PDB, on the other hand, offers a one-step, qualifications-based procurement process that fosters greater collaboration between the owner and the contractor during the design phase. This method enables stakeholders to provide substantial input, ensuring that the final design aligns closely with their needs and expectations. PDB also reduces procurement time and provides flexibility in terms of adjusting the scope or schedule as needed. Notably, PDB has been particularly effective in emergency situations, such as the rapid reconstruction of Baltimore's Francis Scott Key Bridge following its collapse in March 2024. By leveraging PDB, agencies can respond swiftly to urgent infrastructure needs without compromising quality or safety standards.