One hoped-for benefit of the redevelopment of Seven Corners proposed by Fairfax County has been relief from some of the traffic congestion.  However, the results of the FCDOT analysis of the roadway improvements proposed by the task force show that network performance would be unacceptable in critical areas.  Today’s traffic congestion issues are not resolved by high-rise redevelopment.

The task force and FCDOT have developed a proposed road network known as Concept B to serve the high-rise redevelopment.  FCDOT has published an analysis of that network in their Phase II transportation study, and  VDOT is in the process of completing their review of the report.  In an effort to support the VDOT review, comments on the Phase II report have been submitted to provide a community perspective and local knowledge of the traffic situation.

In its Phase II transportation study, FCDOT compared the Year 2040 performance of the Concept B network serving the proposed high-rise redevelopment against today’s development served by today’s roads with Rt 50 widened to 6 lanes.  The principal conclusion of the report is that some intersections would perform better in 2040 with Concept B.  However, the report shows that Concept B performance overall would not be acceptable.  Rt 50 would operate over capacity (LOS F) and all through and turning movements at the intersections of Patrick Henry Drive with both Rt 7 and Rt 50 would operate at LOS F.  The VDOT definition of Level of Service (LOS) F is that traffic delays would be unacceptable to most drivers; roadway network capacity has been exceeded.

The FCDOT  analysis of Concept B made optimistic assumptions about the traffic demand that would be imposed by the high-rise redevelopment.  It assumed that traffic demand would be increased very little.  Despite an increase in floor area from 1.7 M sq ft today to 7.8 M in 2040, AM peak hour traffic would increase only 4%; PM peak hour traffic would increase only 7%. Therefore, the 2040 traffic demand applied to Concept B was nearly the same as the 2040 demand currently projected for the area without additional development.  To the extent that the report underestimated Concept B traffic demand, it overestimated the performance of the network.   The traffic demand assumption and other limitations of the FCDOT analysis and Concept B are discussed in the comments.

A broad conclusion from the FCDOT report is that the traffic currently projected for Seven Corners without additional development would saturate the existing road network even with Rt 50 widened to 6 lanes.  The network would perform at LOS F in 2040.  If the Concept B network were implemented in the 2040 time frame (still without additional development), the network would still be saturated.  Rt 50 and the Patrick Henry Drive intersections would operate over capacity (at LOS F).

Seven Corners is the intersection of four major roads in a very small space.  Rt 50, Rt 7, Wilson Blvd, and Sleepy Hollow Rd carry heavy peak hour traffic loads, and there are limited options for better routing the traffic within the immediate area.  The conclusion is that Seven Corners is not an appropriate site for high-rise, high-density redevelopment.