Fairfax Department of Transportation Predicts Significantly Worsening Congestion for Dulles Corridor Traffic
In a presentation to the Reston Master Plan Special Study Task Force on October 26, the Fairfax County Department of Transportation (DOT) presented analysis forecasting a dramatic increase in traffic congestion through 2030. The study focused on the corridor immediately adjacent to the Dulles Toll Road and highlighted 24 critical road intersections, each assigned a level of service (LOS) from A (free flow, low traffic density) to F (forced flow with demand volumes greater than capacity resulting in complete congestion. Volumes drop to zero in extreme cases).
Of the 24 intersections, the traffic analysis showed current morning peak hour LOS at three Fairfax County Parkway and Reston Parkway intersections was already an F. Two additional intersections were rated as E. There were no intersections rated as A, and only four rated as B LOS.
The analysis then assumed major roadway improvements between 2010 and 2030, including widening of Route 28 to ten lanes including HOV lanes; widening of Fairfax County Parkway to six lanes including HOV lanes; an overpass across the Dulles Toll Road near the County line (Rock Hill Road Overpass); an overpass across the Dulles Toll Road west of Wiehle Avenue (Soapstone Overpass); widening of Centreville Road to six lanes; extension of Sunrise Valley Drive south of Frying Pan Road; completion of improvements to West Ox Road, Coppermine Road, and Reston Parkway; and widening/improvement of Fox Mill Road, Monroe Street, and Frying Pan Road. The analysis did not assume several improvements currently advocated by affected interests, including additional access to the existing Herndon-Monroe parking garage, which would relieve some of the congestion at the critical Fairfax County and Monroe Street intersections with Sunrise Valley Drive.
In 2030, the study predicted the number of F rated intersections will increase from six to fifteen, including degradation of two of the four existing B ratings to F. The analysis ignored the intersections of Monroe Street with Sunrise Valley Drive and the Monroe Street overpass of the Dulles Toll Road , which will be significantly affected by the new Metro station; did not consider Fox Mill Road intersections with Fairfax County Parkway, Monroe Street, and Colts Brook Drive which may be affected; and did not address Sunrise Valley Drive intersections with Thunder Chase Drive, Roark Court, Milburn Lane, Hitchcock Court, and Colts Brook Drive, all in very close proximity to the Metro station.