Dulles Corridor Area Traffic with GMU Forecast for Reston, Fred Costello, September 2010

This is another in a series of papers prepared by Fred Costello, member of the Reston Task Force, on the traffic impacts of proposed development in Reston's TOD areas.  As usual, it's thorough, methodical, and insightful.  It's also complex.  Here is this layman's summary of the paper's conclusions:

The paper examines 16 intersections along the Dulles Corridor in Reston:  The intersections of Sunrise Valley and Sunset Hills as well as the east- and west-bound ramps of the Dulles Toll Road with Hunter Mill, Wiehle, Reston Parkway, and the Fairfax County Parkway.  He examines data for both the morning and evening peak and for open/closed right-hand turns. He measures the percent of vehicles that (a) clear in a light cycle and (b) are stored in a light cycle at present and in 2050 using GMU's projected intermediate residential and non-residential populations from the paper they presented the Reston Task Force.  In short, he makes assesses 128 data points for both the present and the future (2050).   Some very basic findings from this data set--evidenced in the ending spreadsheets--include:

• Today, half--64 of the 128--data points seriously or marginally fail meeting the criteria laid out for success, i.e.--clearing a waiting queue of vehicles in a single light cycle, in traffic hours.  In 2050, he projects that 89 percent of the points measured (70%) will fail under the same conditions. 
• The intersections that currently fail marginally or seriously on all four metrics (AM & PM, % clearing, % waiting)--that is, the worst of the worst--include Sunrise Valley at 7100, Reston Pkwy, and Hunter Mill.  In 2050, the worst of the worst include:
• Sunrise Valley at all four intersections (i.e.--adding Wiehle)
• Sunset Hills at all the intersections except 7100.

The paper provides some partial solutions to this congestion-filled future as depicted on the first page of his report below. 

Those of a quantitative bent will want to read the entire paper where Fred details his assumptions, methodology, and conclusions.  


Dulles Corridor Area Traffic With GMU Forecast for Reston, Fred Costello, September 2010