Reston citizens worried the Silver Line will bring gridlock, WTOP, February 18, 2013

Ari Ashe, wtop.com

RESTON, Va. - Some Reston residents are worried that the opening the first phase of Metro's Silver Line will make traffic worse near one of the stations scheduled to open at the end of the year.

The concern is that extra cars parking at the Wiehle-Reston East station's 2,300 space parking garage could further choke traffic on Wiehle Avenue.

"It's already a focal point for congestion because of the Dulles Toll Road next to it," says Terry Maynard, with the Reston Citizens Association.

"This situation with more cars coming there to park for Metrorail will make a bad situation worse.". . .

Southbound traffic on Wiehle Avenue approaching the Dulles Corridor bridge.

(FC DOT rail planner Nick) Perfili says the level of service grade at the Wiehle Avenue and Sunrise Valley Drive intersection is currently a "D." He says the planned improvement would keep the intersection at its current grade. Without any improvements, it is projected that the intersection would get an "F."

The level of service measure grades intersections on an "A" to "F" scale based on traffic flows, wait times, and the space between vehicles. Level A is wide-open and Level F is total gridlock.

However, Maynard doubts the improvements would have any effect on traffic.

"And it will get worse as more people and jobs come to this area of Reston," says Maynard.

WTOP's full article is available by clicking here.

For the record, FC DOT projects that the corner of Wiehle and Sunset Hills will have a "F-" grade with three minute peak-of-the-peak delays in the evening rush hour under the current Reston Task Force development planning scenario for the Wiehle station area.  Specifically, it foresees an intersection delay of 215 seconds (3-1/2 minutes) at that time (see p. 11 of the FC DOT assessment) under assumptions of "full build"--the completion of all proposed roadway improvements, including the Soapstone connector, and the full completion of the Silver Line. The intersection of Reston Parkway and Sunrise Valley Drive will be worse:  A full 4-minute delay in the evening peak period.

In the ITE level of service (LOS) standards, a rating of "F" begins when traffic delays reach 80 seconds.  Here are the standards for a signalized intersection as published in the federal Highway Capacity Manual:

LOS	Signalized Intersection (Grade, avg. delay/vehicle, general description)
A	≤10 sec        Free flow
B	10-20 sec     Stable flow (slight delays)
C	20-35 sec     Stable flow (acceptable delays)
D	35-55 sec     Approaching unstable flow (approaching intolerable delay, occasionally wait       through more than one signal before proceeding)
E	55-80 sec     Unstable flow (intolerable delay)
F	≥80 sec        Forced flow (jammed)