Public infrastructure projects face mounting pressure to deliver faster and cost less. Yet the procurement model governing most of them - design-bid-build - was designed for an era when sequential workflows and competitive low-bid selection were the primary safeguards. The evidence now points in a different direction.
According to the Design-Build Institute of America (DBIA), design-build now accounts for over 44% of construction spending across the United States - a share that continues to grow as public agencies and state legislatures reassess how infrastructure gets built, financed, and delivered.
Design-Build vs. Design-Bid-Build: A Structural Divide
The core difference between the two approaches is contractual integration. In the traditional design-bid-build (DBB) model, a public owner first hires a designer to produce completed plans, then solicits separate bids from construction contractors. The design firm delivers fully complete documents, and the owner independently solicits bids from contractors to execute the documented scope of work.
Design-build (DB), by contrast, consolidates both responsibilities under a single contract. Instead of the owner coordinating between an architect and a general contractor, one unified team manages both design and construction - streamlining decision-making, reducing risk, and accelerating the project timeline.
The practical consequence is schedule compression. Because the contractor is engaged early, construction can begin as soon as a portion of design is complete, allowing building and design to proceed simultaneously. On large, complex projects, this concurrency can save months or even years.
What the Performance Data Shows
Independent research consistently favors design-build on speed and cost control for complex projects. A University of Texas analysis of 75 design-build and design-bid-build projects for the U.S. Navy found that design-build projects took less time, experienced less cost growth, and were less expensive to build. A separate Construction Institute study found that design-build projects had 6% fewer change orders, 102% faster delivery speed, and 3.8% less cost growth compared to design-bid-build.
Cost predictability is another differentiating factor. Design-bid-build's competitive bidding process can yield lower initial costs, but because contractors are absent from the design phase, unforeseen conflicts often result in change orders and budget adjustments during construction. Design-build offers greater cost predictability, as early collaboration between designer and contractor helps align budgets and minimize unexpected expenditures.
Design-build is not universally superior. Design-bid-build suits linear project sequences where each step is completed before the next begins. It works best when the owner needs complete design control and for less complex projects that are budget-sensitive but not time-critical. For straightforward public works with well-defined scope - such as a standard road widening or minor civic building - the transparency and competitive pricing of DBB remain legitimate advantages.
The Method at a Glance
| Factor | Design-Bid-Build (DBB) | Design-Build (DB) |
|---|---|---|
| Contract Structure | Two separate contracts | Single integrated contract |
| Timeline | Sequential - typically longer | Overlapping phases - compressed |
| Cost Predictability | Lower estimate upfront; change orders common | Greater early certainty; fewer change orders |
| Risk Allocation | Owner bears design/coordination risk | Design-builder assumes integrated delivery risk |
| Transparency | High - competitive bidding | Moderate - best-value procurement |
| BIM/Tech Integration | Possible, but often siloed | Natural fit under single data environment |
| Best Fit | Simple, budget-driven, or mandated DBB projects | Complex, fast-track, or highly integrated projects |
State-Level Reform and Expanding Authorization
Legislatures across the U.S. are actively expanding design-build authorization. Kentucky Governor Andy Beshear announced a design-build team executing a $9.5 million project to improve highway safety along interstates prone to wrong-way crashes. Ohio and Kentucky jointly announced the Brent Spence Bridge design-build team - one of the most significant interstate infrastructure projects in the region.
Governors nationwide are exploring alternative delivery models alongside innovative funding and financing approaches. As funds flow from the Infrastructure Investment and Jobs Act (IIJA) and related legislation, these models are being leveraged to accelerate projects, reduce costs, and free public resources for other priorities.
State-level approval frameworks vary significantly. In Washington State, all public bodies - including state agencies, counties, cities, school districts, and special purpose districts - may use design-build contracting for eligible projects, but agencies must first obtain approval from the state Project Review Committee. This tiered authorization model reflects a broader pattern: states are opening the door to design-build while maintaining oversight mechanisms that protect public accountability.
Beyond Design-Build: The DBFR and P3 Spectrum
Design-build is not a monolithic model. On the more expansive end of the delivery spectrum sits design-build-finance-run (DBFR) - sometimes structured as design-build-finance-operate-maintain (DBFOM) under public-private partnership (P3) frameworks.
Under the design-build-finance (DBF) model, a single contract covers design, construction, and full or partial financing of a facility. Long-term maintenance and operation remain with the project sponsor but could be included in a separate agreement. This approach captures design-build efficiencies while allowing the sponsor to defer financing - fully or partially - during construction.
P3s have traditionally been concentrated in the transportation sector, but their use has expanded into energy, broadband, school infrastructure, water, and affordable housing. While often presented as a solution to constrained public finances, the primary benefit of P3s lies in their ability to accelerate delivery, reduce costs, and foster innovation.
For public authorities weighing these options, the critical question is how much operational risk - not just construction risk - to transfer to the private sector. P3 structures can unlock private capital for capital-constrained governments, but they demand sophisticated contract structuring and long-term performance monitoring.
BIM and Digital Twin Integration: Design-Build's Natural Advantage
The structural integration of design-build creates a data environment inherently more compatible with Building Information Modeling (BIM) and digital twin workflows. When a single team owns both design and construction, model data does not need to cross contract boundaries - reducing the rework and information loss that plague siloed DBB projects.
Governments in North America, Europe, and Asia-Pacific are mandating BIM usage for public infrastructure planning, reinforcing the software's role in achieving sustainability, cost transparency, and lifecycle asset management. Construction firms use design software to simulate construction sequencing, energy performance, and clash detection - all of which mitigate risks before physical work begins. These capabilities are critical in an industry where errors and inefficiencies can significantly impact budgets and timelines.
Real-world results are beginning to quantify the savings. A 2024 Caltrans project used BIM to create a digital model of a roadway impacted by a landslide as part of a design-build stabilization effort. The model enabled Caltrans to save $520,000.
Digital twins are moving from pilot projects to enterprise platforms, driven by owner demand for lifecycle value rather than short-term delivery efficiency. Interoperability is becoming a priority, with increasing focus on open standards and integration across BIM, GIS, IoT, and asset management systems. Public sector infrastructure projects are accelerating adoption due to aging assets, climate resilience needs, and budget constraints.
For design-build teams working under a shared interoperability framework, a Common Data Environment (CDE) can serve as a live project record throughout construction - and become the foundation for the asset owner's ongoing facilities management platform.
Barriers, Risks, and Equitable Competition
The case for design-build is compelling, but three friction points consistently slow broader public adoption:
1. Risk allocation and contract structuring. Design-build shifts significant design coordination risk to the private partner. While this can benefit public owners, the design-builder is bidding on a project not yet fully designed - introducing inherent uncertainty. Poorly structured contracts that fail to define scope, performance benchmarks, and change-order protocols clearly can produce disputes as significant as those in DBB arrangements.
2. Market competition and small-firm access. Design-build procurement typically evaluates contractors on qualifications rather than price alone, favoring large, integrated firms with in-house design and construction capabilities. This can disadvantage smaller regional contractors and independent design firms. Public agencies implementing design-build must actively structure procurements to preserve competitive market access.
3. Statutory and regulatory constraints. Public and municipal entities mostly use design-bid-build as required by state statutes; some private developers also rely on it when seeking low-cost bids. Expanding design-build requires legislative action in many jurisdictions - a process that moves slowly relative to project pipeline demands. States that have already acted, as explored in the Army's parallel reform of military construction delivery, offer useful templates for enabling legislation.
Key Takeaways for Construction and Public Procurement Professionals
- Design-build delivers measurable schedule and cost advantages on complex, fast-track, or highly integrated projects - but is not the optimal choice for all public procurement scenarios.
- State-level procurement reform is accelerating, with governors and legislatures authorizing design-build for a broader range of project types, particularly as IIJA funding flows.
- BIM and digital twin integration align naturally with design-build, enabling a single team to maintain a live data model from concept through commissioning - supporting lifecycle asset management.
- DBFR and P3 models extend the value proposition for capital-constrained public authorities, but require more sophisticated contract structuring and risk-sharing frameworks.
- Equitable competition requires deliberate design: procurement frameworks must ensure smaller and regional firms can meaningfully compete alongside large integrated design-builders.
As procurement reform reshapes how public sector projects are contracted, design-build stands as both an opportunity and a test of institutional readiness - demanding not just enabling legislation, but the analytical and contractual sophistication to deploy it effectively.
