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Innovative Technology helps deliver the Warrenton Southern interchange Project

Carl Kaczmarek, PE 

The previously signalized intersection at US Route 15/17/29 and Business US Route 15/17/29 in Fauquier County, Virginia, experienced a high volume of crashes, caused traffic delays for a growing community, and did not provide accommodations for pedestrian or bicycle traffic. The Virginia Department of Transportation (VDOT) selected design-build contractor Shirley Contracting Company, LLC (Shirley) and design service firm Dewberry to design and construct a solution that would alleviate the cumbersome congestion and safety concerns. With Lord Fairfax Drive to the east and Business US Route 15/17/29 to the west, the $19.7-million design-build project kicked off in 2018 and opened to traffic in 2020. 

The design team used Bentley’s OpenRoads technology in all aspects of the project, which allowed for real-world contextualization of the project site and elements in a 3D deliverable. The software was used to develop a 3D model for the construction phase of the project, and the team harnessed its capabilities during the design-build procurement and final design development phases. This included quickly developing limits of construction and quantities estimates for Shirley during the development of the requests for proposal (RFP) concept, and analyzing a multi-stage traffic control diversion with grade changes
of up to 30 feet. 

Challenges and Sustainability

While every design-build and complex transportation project comes with its own unique challenges, learning a new technology presents a major obstacle for this project. The team attended forums and training sessions on 3D deliverables to better understand how the use of this technology would impact the project, VDOT, and its stakeholders. 

In addition to utilizing new technology, the Warrenton Southern Interchange project involved positive sustainable impacts. In designing the interchange, we provided enhancements that allowed for removal of extraneous existing pavement to maintain a phosphorus removal requirement of less than 10 pounds per year. This included reducing the proposed pavements, maximizing the use of existing pavements, and relocating the proposed park-and-ride lot within the existing roadway. Our unique design concept also reduced disturbance to forested areas by approximately 85,000 square feet when compared to the RFP design. 

This project was located within the Journey Through Hallowed Ground (JTHG) National Heritage Area. As part of their mission to preserve the cultural landscape of this region, the Living Legacy Project aims to honor fallen soldiers of the American Civil War by planting one tree for each of the 620,000 soldiers who gave their lives. Our design was able to provide 70,000 feet of landscaping, developed by our landscape architects in accordance with the Living Legacy Project’s tree palette for the project’s character zone. 

Providing these sustainable enhancements had its challenges, requiring coordination with the town of Warrenton, VDOT, and the JTHG to determine a cohesive final design that met the desires of each stakeholder. In the end, everyone’s objectives were met through innovative design concepts and approaches. 

Breakthroughs and Awards

Shortly after the Warrenton Southern Interchange project was complete, VDOT requested that Dewberry participate in the Industry 3D Task Force. In this, our engineers worked with VDOT to offer their perspectives on Virginia’s expectations of their consultants. Through many correspondences, Dewberry helped define what 3D deliverables and model management will look like in Virginia for years to come.

In addition, the project was used as an example of innovation within the design-build process during the University of Virginia’s 2018 session of the Transportation Project Management Institute and selected for a Merit Award at the Virginia American Council of Engineering Companies (ACEC) Engineering Excellence Awards in 2022. 

Inclusive of the time taken to master the new software, the design team achieved plan approval within 12 months of notice to proceed. This success continued through construction as the team received the highest Construction Quality Control Program (CQIP) score at the time (94.38 on a 100 point scale), and a Design-Builder Performance Evaluation (DBPE) of a 4.0. Additionally, the project has provided the firm exciting new opportunities for growth in the region. 

Carl is a senior associate and roadway department manager for Dewberry’s mid-Atlantic transportation group. He has been a full-time employee since January 2009 and is currently licensed in Virginia, Maryland, and Washington, D.C. Carl was selected as one of ENR’s Mid-Atlantic Top Young Professionals in 2021. 


Carl Kaczmarek is a senior associate and roadway department manager for Dewberry’s mid-Atlantic transportation group. He has been a full-time employee since January 2009 and is currently licensed in Virginia, Maryland, and Washington, D.C. Carl was selected as one of ENR’s Mid-Atlantic Top Young Professionals in 2021.