The document outlines the Reston Network Analysis for Fairfax County, Virginia, focusing on a detailed study of the street grid and future traffic conditions projected for 2050 without mitigation. Key findings include significant vehicle trip reductions linked to increased transit use and the identification of problem intersections experiencing high levels of congestion. The report also suggests mitigation options to improve traffic flow and prepare for anticipated development in the area.

1. County of Fairfax, Virginia
Reston Network Analysis
2050 Unmitigated Results
January 11, 2016
Kristin Calkins
Fairfax County Department of Transportation

2. County of Fairfax, Virginia
Agenda
• Study Purpose
• Project Progress Overview
• Methodology
• 2050 Unmitigated Modeling Results
• Mitigation Options
• Next Steps
• Questions and Answers
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3. County of Fairfax, Virginia
Purpose of Study
• Conduct a detailed analysis of the grid of streets
to determine:
– Number of lanes between and at intersections
– How to best serve pedestrians, bikes and transit
– Right-of-way needs
• Assign urban street types and modal emphasis
based on Department of Rail and Public
Transportation Multimodal System Design
Guidelines
• Conduct a phasing analysis of when larger
projects are needed
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4. County of Fairfax, Virginia
Reston Network Analysis Tasks
1. Data Collection – done
2. Existing Conditions – done
3. Future Conditions – 2050 unmitigated underway
– Determine Grid of Streets
4. Phasing Analysis
5. DRPT Classifications
6. Specific location improvements for additional study
– Reston Parkway
– Sunrise Valley Drive @ Fairfax County Parkway
– Spring Street @ Fairfax County Parkway
– Rock Hill Bridge
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5. Data
Collection
• Traffic
Counts in
June 2015
• Travel Time
Runs
Existing
Conditions
• Capacity
Analysis
• Level of
Service
Test Grid of
Streets (2030
& 2050)
• Traffic
Forecasting
Capacity
Analysis
• Level of
Service
Mitigation
• Signal re-
timing
• New links
• Turn lanes
• Additional
lanes
Roadway
Classification
• DRPT Design
Guidelines
• Bike lanes
• Sidewalks/
Pedestrian
routes
• On-Street
Parking
• Transit Routes
Finalize Grid of
Streets (2030
& 2050)
Based on:
• Advisory Group
input
• Stakeholder
input
• Community
input
Phasing
Analysis
• Prioritization
of larger
projects
Network Analysis Project Process
Advisory Group input, Stakeholder input, Community input

6. County of Fairfax, Virginia
Project Progress Overview
• Completed data collection
• Finalized existing conditions
• Begun analyzing future conditions (2030
& 2050)
– Developed ITE-based vehicle trips for 2030 and 2050
• Significant vehicle trip reductions due to transit, TDM, and
bike and pedestrian increases associated with the Metro
station and TOD development
– Developed the 2050 VISUM model
– Completed 2050 VISUM preliminary vehicle trip
assignment without mitigation
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7. County of Fairfax, Virginia
Methodology
• County model
– Seed trip tables
– Roadway network
• VISUM
– Model development including local roads & driveways
• VISUM model input
– Origin/Destination (O-D) trip tables from County and Regional
Model
– ITE-based trips
– SYNCHRO for signal timing optimization
• VISUM model output
– Intersection delay and level of service
– Link volumes
– Turning movements volumes and LOS
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8. County of Fairfax, Virginia
Reston VISUM Model
Tysons
Reston
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9. County of Fairfax, Virginia
2050 Unmitigated
VISUM Modeling Results
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10. County of Fairfax, Virginia
2050 Unmitigated Results
• Stop controlled intersections:
– Overall LOS
– Overall Delay
• Signalized intersections:
– Overall LOS
– Overall Delay
– LOS by movement
– Delay by movement
– Volumes for each movement
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11. County of Fairfax, Virginia
LOS Results
• Of 42 key signalized intersections in the study area,
in 2050 unmitigated the following operate at Level
of Service F:
– AM peak hour: 24
– PM peak hour: 26
– AM and PM peak hours: 22
• Existing development is 31,812,244 square feet
• 2050 development is approximately 100,000,000
square feet (including Innovation TSA)
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12. County of Fairfax, Virginia
Existing Peak Hour LOS (Page 1)
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13. County of Fairfax, Virginia
2050 Unmitigated Peak Hour LOS (Page 1)
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14. County of Fairfax, Virginia
Existing Peak Hour LOS (Page 2)
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15. County of Fairfax, Virginia
2050 Unmitigated Peak Hour LOS (Page 2)
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16. County of Fairfax, Virginia
Existing Peak Hour LOS (Page 3)
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17. County of Fairfax, Virginia
2050 Unmitigated Peak Hour LOS (Page 3)
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18. County of Fairfax, Virginia
LOS Results
• Intersections with delay of 120 seconds or
more
– AM peak hour: 17
– PM peak hour: 19
– AM and PM peak hours: 14
• LOS E is the standard for
the Reston Transit Station
Areas
Delay (s/veh)
LOS
Signalized
Intersections
Unsignalized
Intersections
A ≤ 10 ≤ 10
B > 10 - 20 10 - 15
C > 20 - 35 15 - 25
D > 35 - 55 25 - 35
E > 55 - 80 35 - 50
F > 80 ≥50
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19. County of Fairfax, Virginia
2050 Unmitigated Problem Locations
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20. County of Fairfax, Virginia
2050 Unmitigated Problem Locations (cont.)
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21. County of Fairfax, Virginia
2050 Unmitigated Problem Locations (cont.)
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22. County of Fairfax, Virginia
2050 Unmitigated Problem Locations (cont.)
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• Intersections with Delay over 120 Seconds
1. Frying Pan Road & Sunrise Valley Drive
2. Frying Pan Road & Centreville Road
3. Centreville Road & Sunrise Valley Drive
4. Centreville Road & the Eastbound DTR Ramps
5. Centreville Road & the Westbound DTR Ramps (PM only)
6. Monroe Street & Fox Mill Road (AM only)
7. Monroe Street & Sunrise Valley Drive (PM only)
8. Spring Street & Herndon Parkway
9. Fairfax County Parkway & Sunrise Valley Drive
10. Fairfax County Parkway & New Dominion (PM only)
11. Fairfax County Parkway & Baron Cameron Avenue

23. County of Fairfax, Virginia
2050 Unmitigated Problem Locations (cont.)
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• Intersections with Delay over 120 Seconds
12. Town Center Parkway & Baron Cameron Avenue
13. Town Center Parkway & Sunset Hills Road
14. Reston Parkway & Baron Cameron Avenue
15. Reston Parkway & Sunset Hills Road
16. Reston Parkway & Sunrise Valley Drive
17. Reston Parkway & South Lakes Drive
18. Sunrise Valley Drive & Soapstone Drive (PM only)
19. Wiehle Avenue & Eastbound DTR Ramps (AM only)
20. Hunter Mill Road & Sunrise Valley Drive (AM only)
21. Hunter Mill Road & Westbound DTR Ramps
22. Hunter Mill Road & Sunset Hills Road (PM only)

24. County of Fairfax, Virginia
2050 Unmitigated Data
• Stop controlled intersections:
– Overall LOS
– Overall Delay
• Signalized intersections:
– Overall LOS
– Overall Delay
– LOS by movement
– Delay by movement
– Volumes for each movement
• Link volumes
• Driveway volumes
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25. County of Fairfax, Virginia
2050 AM Peak Hour Data
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26. County of Fairfax, Virginia
PM 2050 Peak Hour Data
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27. County of Fairfax, Virginia
2050 AM Peak Hour Data
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28. County of Fairfax, Virginia
2050 PM Peak Hour Data
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29. County of Fairfax, Virginia
AM Peak Hour Site Trips and Link Volumes
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30. County of Fairfax, Virginia
PM Peak Hour Site Trips and Link Volumes
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31. County of Fairfax, Virginia
Existing Reston TSA Walk-shed
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32. County of Fairfax, Virginia
2050 Reston TSA Walk-shed
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33. County of Fairfax, Virginia
2050 Walkshed
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Distance Existing With Grid Increase
0-.25 mile 0.06 0.10 66%
.25 - 0.5 mile 0.22 0.46 108%
.05-1.0 mile 1.86 2.52 35%
Total 2.15 3.09 44%
Walkshed Area (square mile)

34. County of Fairfax, Virginia
Mitigation
• Mitigation reduces vehicle congestion
• Mitigation reduced delays experienced at
intersections
• Mitigation improves the reliability of travel times
through an area (for both buses and vehicles)
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35. County of Fairfax, Virginia
Mitigation Options
• Mitigation Measures - Tiered Approach
– No right of way impact
– Some right of way impact
– Large scale mitigations if needed
– Consultation with Advisory Group and
Stakeholders
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36. County of Fairfax, Virginia
Mitigation Measures
No Right of Way Impact
•No/Low Cost: Intersection Reconfiguration
– Optimized signal timing and phasing
– Lane configuration modification
Westwood Center Dr. @ Route 7 (2013)
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Westwood Center Dr. @ Route 7 (2015)

37. County of Fairfax, Virginia
Mitigation Measures (cont.)
No Right of Way Impact
•Existing and Potential Future Signals
– Adding/removing traffic signals
– Adding/modifying stop control
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Westwood Center Dr. @
Sheraton Tysons Dr. (2013)
Westwood Center Dr. @
Sheraton Tysons Dr. (2015)

38. County of Fairfax, Virginia
Mitigation Measures
Some Right of Way Impact
• Turn lanes
– Left and Right turn lanes
– Add storage
– Reduces queuing on to through movement
• Additional through lane
• Additional grid link
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39. County of Fairfax, Virginia
Mitigation Measures
Alternative Intersection Treatment
• Median U-Turn/Superstreet
– Eliminate left turn movement for side streets
– Increases thru movement green time
– Additional needed ROW to provide turn radius
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40. County of Fairfax, Virginia
Mitigation Measures
Large Mitigation Measures
• Underpass/Overpass
– Provides for an uninterrupted thru movement
• Only done in close coordination with Advisory
Group and Stakeholders after all other mitigation
measures have not worked
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41. County of Fairfax, Virginia
Next Steps
• Apply no ROW impact Mitigation Measures
– Modifications to the lane configuration
– Signal timing and phasing optimization
– All-way stop vs. two-way stop evaluation
– Additional traffic signals
• Meet with Stakeholder Group on no ROW impact
Mitigation Measure LOS Results
• Develop possible mitigation measures for problem
locations that remain to discuss with Advisory Group
• Meet with Advisory Group on possible some-ROW
impact mitigation measures
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42. County of Fairfax, Virginia
Schedule
Task Description
1A Land Use and Networks - Task is Complete
1B Traffic Counts - Task is Complete
2A Establish Existing Conditions - Task is Complete
2B Calibrate Against Existing Conditions - Task is Complete
3A2 Analyze Future Conditions (2050)
3A1 Analyze Future Conditions (2030)
3B Simulation of the Dulles Toll Road
3C Microsimulation - Optional
4A Meetings/Presentations
5A Phasing Analysis - Existing Conditions
5B Phasing Analysis - 2050 - Optional
6 Determination of DRPT Guidelines Roadway
Classification
7 Documentation
8 Reston Parkway Capacity Improvements
9 Fairfax County Parkway & Spring Street Interchange
10 Fairfax County Parkway & Sunrise Valley Drive
11 Rock Hill Bridge at Sunrise Valley Drive
12A Meetings/Presentations
Feb-15May-15 Jun-15 Jul-15 Aug-15 Sep-15 Oct-15 Nov-15 Dec-15 Jan-16 Sep-16 Oct-16Mar-16 Apr-16 May-16 Jun-16 Jul-16 Aug-16
1/11/16
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43. County of Fairfax, Virginia
Questions & Comments
For questions and comments about the study please
contact:
Kristin Calkins: Kristin.Calkins@fairfaxcounty.gov
(703) 877-5710
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