1. Tysons Corner Consolidated Transportation Impact Analyses (CTIAs)
BOS Transportation Committee
May 8, 2012

2. Tysons Purpose of CTIAs
Analyze impact of pipeline developments. Individual impact studies (TIAs) do not consider pipeline developments
Analyze 2030 and 2050 levels of development for the analysis area and determine associated mitigation measures
Finalize grid of streets including
Functional classification
Number of lanes between and at intersections
Accommodation of transit, bikes, and pedestrians
Right-of-way needs
Create a Tysons-wide simulation model
Bullet 1 – the necessary adjustments would provide an acceptable level of traffic flow, be cost effective, and identify the minimum ROW required with the least negative impacts to adjacent properties and the environment by taking into consideration the provisions of the Tysons comprehensive plan
Bullet 2 – Three levels of development are being tested – 1. Plan Buildout including Rezonings, 2. Rezonings with existing development, and 2030 GMU Forecast

3. Tysons East is used as an example
Macroscopic Models – Regional Transportation Model
Public policy, regionally significance projects
Mesoscopic Models – Sub Area Extractions
Link regional trip purpose to details of micro-simulation models
Microscopic Models – Street Traffic analysis
“Visualization” of solutions, detailed intersection operations analysis
Tysons East is used as an example

4. MWCOG Regional Model
This is an overview of the entire MWCOG model. The entire model is heavily concentrated in the Metro Washington area which includes a great level of detail in Fairfax County. The red polygon shoes the full extent of the VISUM model while the smaller red polygon represents the Tysons East study area.

5. Tysons East Analysis Area
-This image is of the Tysons East CTIA Analysis Area.
-The CTIA analysis area is defined as a coherent area of Tysons where rezoning activity is prevalent and where the traffic impact of the rezoning activity is significant. It is also typically a sub-district as defined in the Tysons Comprehensive Plan with adjustments resulting from taking into consideration traffic impact and the grid of streets. Gateways providing access and egress to and from the analysis area will be included in the analysis.

6. Tysons Central Analysis Area
-Like the last image, this is the Tysons Central Analysis Area

7. Tysons West Analysis Area
-Finally, this is the Tysons West Analysis Area

8. Volume/Capacity Sample Output
-This map shows a sample result, output by the model of a Volume-to-capacity ratio map.
(Explain how these are used and how we are coordinating this data with the developers and their consultants for review.)

9. Measures of Effectiveness (MOE)
Level of Service and Delay at Intersections
Vehicles Mile Travel
Hours of Delay
Average Speed
Travel Time
Queue Length

10. CTIA Process with Stakeholders
Weekly meetings
Inclusive, collaborative process
Full access to information
Analyze suggestions from stakeholders
Many iterations of testing alternative mitigation measures – what transportation measures are required to accommodate proposed land use intensity levels?
Focus is cost-effectiveness

11. CTIA Analysis Process – Tiered Approach
No right of way impact (traffic reassignment, signal modification, lane restriping)
Some right of way impact (turn lanes, additional through lane, additional grid link)
Additional mitigation
-Mention use of CDPs
-describe large scale mitigations.
-used in conjunction with lesser mitigations (ex: lane config changes depending on what large scale mitigation used)

12. TIER 2 – ROW Impacts

13. TIER 2 – ROW Impacts

14. TIER 3 – Additional Mitigation

15. I-495
Dolley Madison

16. Conclusions (Tysons East)
Traffic impacts were mitigated
Identified right-of-way needs
Finalized grid of streets
Next Steps
Submit analysis to VDOT to meet VA traffic impact study requirements
Plan amendment