Here is the summary of the VDOT assessment (p. 16) with our highlighting of key points:
Due to significant concerns with the cumulative impacts of other development within the region, deficiencies in the Synchro analyses, and trip making assumptions the VDOT does not believe that this report contains “sufficient information to evaluate the system of new and expanded transportation facilities” and suggests that the report be refined and resubmitted incorporating the comments within this letter to determine if the transportation facilities will indeed support the proposed development as required by 24VAC30-155-30.VDOT's concerns are all the same concerns RCA has voiced about the current draft plan text: Lots of goals, no means to get there. And, indeed, Reston's transit station areas could easily end up with a Level of Service "F"--or GRIDLOCK. Indeed, the assessments we have seen suggest that is the likely outcome.
Furthermore, an inherent inconsistency is introduced in the proposed amendment by introducing a level of service standard of E, but not proposing mitigation measures to achieve this standard. If Fairfax County finds it necessary to stipulate a level of service standard the following methods should be considered: reduced intensity of development, an expanded transportation network, or a level of service standard of F. As noted in VDOT’s Traffic Impact Analysis Regulations Administrative Guidelines, “just identifying future transportation needs is not sufficient.”
The lack of any analysis of the DTR, the imbalance between development intensity and transportation capacity, and the failure to address level of service F situations are all significant concerns. Without addressing these major items, if all development proposed by the Comprehensive Plan Amendment be approved and constructed, there may be failing levels of service many hours of the day with constrained/limited mobility for the movement of goods and people.
As VDOT says, the county needs "reduced intensity of development, an expanded transportation network, or a level of service standard of F." We do not believe an LOS "F" is acceptable and the county may need to both reduce development intensity AND expand the transportation network to achieve a marginally higher LOS "E."