The purpose and need of the project was to improve operations, increase connectivity, and address pedestrian and bicyclist safety concerns. Issues surrounding these focus areas had increased over time given that the interchange remained generally unchanged since its construction with the Pentagon Reservation prior to World War II in the 1940s. The reconfiguration emphasizes safety improvements for drivers, pedestrians, and bicyclists by incorporating pedestrian facilities and traffic calming measures, such as the roundabouts and RRFB at shared-use path crossings. The changes have also provided easier access to regional community, social, and economic facilities, national parks and monuments, and recreational amenities in the area.

This project required a significant number of stakeholders and coordination with each. Stakeholders included the Virginia Department of Transportation, Arlington County, Washington Headquarters Services (WHS), the Department of Defense, the Washington Metropolitan Area Transit Authority, and the National Park Service. It was also important to maintain uninterrupted access to the Pentagon Reservation throughout construction.   

In addition to the roadway and interchange design, our firm provided all engineering design and environmental permitting services, including roundabout design and operational analysis; hydraulic design and stormwater management analysis; traffic engineering, including temporary traffic control, transportation management, signing and marking, roadway, and roundabout lighting; and interchange and roundabout landscaping design. Our survey and environmental team completed a detailed tree location and species survey to identify and establish tree protection areas. Our landscape architects designed a plan to replace the impacted landscaping and proposed new elements that were consistent with the surrounding area and native species.