Rinker Design Associates, P.C. (RDA) provided professional engineering services for the design of Stringfellow Road (Route 645) from Fair Lakes Boulevard (Route 7735) to Lee Jackson Memorial Highway (Route 50). This design work also included the intersection of Stringfellow Road at Route 50 and the associated approaches. The roadway was technically administered by VDOT but was designed per Fairfax County’s direction. The project consisted of widening a two-lane roadway to a four-lane divided roadway with sidewalks and trails, curb and gutter, and a raised median for the length of 2.02 miles. The project passed through a densely populated, residential corridor with several public facilities including a library, schools, and parks as well as several stream crossings. One of the main design issues was the major stream crossing of Little Rocky Run. In addition, the corridor had major utilities, including a newly installed 24-inch water main, several large bore aviation fuel pipelines (6 inches to 36 inches in diameter) that serve Dulles Airport’s fuel farm, and other standard overhead and underground utilities. RDA’s extensive utility coordination efforts, which resulted in a savings of more than $4 million in construction costs and more than a year of advancement to the project schedule, received high marks on this project. As the Prime Consultant for this project, RDA provided complete right of way and construction plans for the following elements:

• Roadway design
• Hydraulic design (including bridge H&HA and scour analysis)
• Extensive utilities coordination
• Retaining wall design
• Traffic engineering analysis and design (including traffic data collection and recommendations)
• Signage and pavement marking plans
• Signalization design
• Lighting plans and ITS
• Permit sketches
• Supplemental survey data with roadway design
• Construction coordination and support