The city council work session reviewed proposed designs for improvements at the intersection of Chain Bridge Road and 123. Three options were presented: Option 1 removed the right turn lane but preserved some buffer; Option 2 added the turn lane but removed all buffer; Option 3 shifted the road west and retained most of the buffer. The recommended option was Option 3, which excludes the turn lane, includes a shared use path, sidewalk, retaining wall, and preserves the buffer with enhanced landscaping. The council will be asked to advance this project, which has $10.75 million in funding and is estimated to cost $11.4 million. Construction would occur from 2025-2026 after design, right of way acquisition, and utility relocation

1. City Council Work Session
September 27, 2022

2.  Review previous recommended design
 Review community feedback
 Review updated recommended design
 Discuss next steps
2

3. 3

4. 4
Summary of Primary Benefits
 57% Reduction in Overall Delay
◦ 71% Reduction SB123
◦ 53% Reduction NB 123
 42% Reduction in Conflict Points
 12% - 75% Reduction in Queue Length
 Enhanced School Bus Stop Safety
 Expanded Multimodal Connections
Summary of Concept
 Removes east side frontage road signals
 Converts west side frontage to one-way inbound
 Relocates exiting Cobbdale traffic to new signal
 Adds a sidewalk on west side frontage road
 Adds a protected dual left turn lane from SB CBR
to Eaton (replaces single lane permissive left)

5. 5
Community Outreach Began January 2022
Five Initial Concerns
1. Enhance pedestrian and multi-modal facilities
2. Condense and improve school bus stop(s)
3. Eliminate mini-roundabout at Norman Ave
4. Provide dedicated right turn lane at the new signal
5. Keep two-way traffic between Assembly & Norman Ave
Additional Concerns
6. Complete eastern improvements, eliminate work west
of Chain Bridge Road
7. Preserve the green buffer between Chain Bridge Road
& the service road





6.  Located within VDOT Right of Way
 Features natural berm
 Approx. 0.8 Acres
 Variety of trees, shrubs, vines
6

7.  264 total trees inventoried, 3” & larger*
◦ 105 “Good” condition (40%)
◦ 105 “Fair” condition (40%)
◦ 25 “Poor” condition (9%)
◦ 29 “Dead” condition (11%)
 Primarily deciduous species (not evergreen)
 Southern half of buffer is widest, most effective
 Visual buffer enhanced by tangle of vines
◦ Vines may contribute to declining tree health
◦ 39 of 105 “Good” trees, 67 of 105 “Fair” trees have vines
* Tree condition assessment completed by Wetland Studies and
Solutions, Inc., August-September 2022
7

8. 8
N
 One-way traffic configuration on Service Road
 Southbound Chain Bridge Rd dedicated right turn lane into Cobbdale
 Neighborhood sidewalk on west side of Service Road
 Shared-use path along Chain Bridge Road
 Existing boxwoods & trees along west side of Service Road

9. 9
Right Turn
Lane
Shared-
Use Path
Sidewalk
Hedges
Preserved
Buffer
Preserved
Recommend
Option 1 X    X X
Option 2     X X
Option 3 X   X  
 Developed three design modifications
 Each includes a different combination of design components
 Each has trade-offs, varying impacts to buffer

10. 10
Right
Turn Lane
Shared-
Use Path
Sidewalk
Hedges
Preserved
Buffer
Preserved
Recommend
Option 1 X    X X
 Similar to “Recommended Design” from July Council meeting EXCEPT:
◦ Right turn lane into Cobbdale removed
◦ Shared-use path shifted west towards service road
◦ Results in 10% or less of existing buffer preserved; narrow strip available for replanting

11. 11
Right Turn
Lane
Shared-
Use Path
Sidewalk
Hedges
Preserved
Buffer
Preserved
Recommend
Option 2     X X
 Same as Option #1, but adds in right turn lane into Cobbdale
 None of existing buffer preserved, very limited area for replanting

12. 12
Right Turn
Lane
Shared-
Use Path
Sidewalk
Hedges
Preserved
Buffer
Preserved
Recommend
Option 3 X   X  
 Shift one-way service road west to maximize existing right of way
 Existing west-side landscaping & hedges removed; construct retaining wall & fence/landscape
 Majority of existing buffer to remain undisturbed south of Norman Ave.

13. 13
Right Turn
Lane
Shared-
Use Path
Sidewalk
Hedges
Preserved
Buffer
Preserved
Recommend
Option 1 X    X X
Option 2     X X
Option 3 X   X  

14. 14

15. 15
 Recommended Build Scenario
◦ Includes shared-use path (shifted to the west)
◦ Removes right turn lane into Cobbdale
◦ Shifts one-way road west, which impacts hedges
◦ Preserves the buffer & the berm
◦ 111 live trees and 29 dead trees to be removed (of 264 total inventoried)
 85% of this tree removal is within the area of the new traffic signal
 Arborist’s Recommendations for Overall Health & Enhanced Buffer
◦ Forest thinning – primarily targeting dead and poor condition trees
◦ Management program – removal of vines & invasive species
◦ Supplemental planting – evergreen screening plants in thin areas and along path

16. 16
 Design Option 3
◦ Right Turn Lane Excluded
◦ Shared-Use Path
◦ Sidewalk
◦ Retaining Wall
◦ Buffer Maintained with
Enhanced Landscaping

17. 17
 Design Option 3
◦ Right Turn Lane Excluded
◦ Shared-Use Path
◦ Sidewalk
◦ Retaining Wall
◦ Buffer Maintained with
Enhanced Landscaping

18. 18
 Improvements primarily constructed within existing right of way
 Limited utility impacts anticipated
 New traffic signal north of Eaton Place constructed by VDOT (I-66)
 City has $10,750,000 in NVTA 70% funding available
◦ Funding subject to rescoring by NVTA for Congestion Reduction Relative to Cost (CRRC)
◦ Anticipated to meet or exceed CRRC rating from original roundabout concept
◦ City may seek additional funds at later date as required
 Estimated Project Budget (Recommended Option)
◦ Engineering & Development: $ 750,000
◦ Right of Way & Utilities: $ 1,200,000
◦ Construction & Oversight: $ 9,450,000*
Total Budget: $11,400,000*
* Includes 30% Construction Contingency & 11% Inflation Factor

19. 19
◦ Fall 2022: Seek Council concurrence to advance project
◦ Fall 2022: NVTA evaluation of updated concept
◦ Fall – Winter 2022: Design of interim safety retrofit for dual-lefts
◦ 2023: Complete field survey and detailed project design
◦ 2024 – 2025: Right of way acquisition and utility relocations
◦ 2025 - 2026: Construct Project

20. 20