The document summarizes an informational meeting about opening a new Diverging Diamond Interchange (DDI) at Interstate 66 and Route 15 in Prince William County, Virginia. It provides details on the project status and completion timeline, an overview of how traffic will flow through the new DDI configuration, and comparisons of traffic volumes between the new DDI and Virginia DOT's first DDI. The meeting included simulations of traffic flow, informational exhibits, and representatives available to answer questions.

1. Opening of the Diverging Diamond Interchange
Interstate 66/Route 15 in Prince William County
Public Information Meeting
Christiana Briganti-Dunn, PE, CCM
Design-Build Program Manager
Virginia Department of Transportation
Jan A. Sherman
Design-Build Project Manager
The Lane Construction Corporation
December 7 and 13, 2016

2. Tonight’s Meeting
• Project Status
• Opening the Diverging Diamond Interchange
• Detour for One Night
• How to Navigate through the New DDI
• Project Schedule and Cost Updates
• Stations Around the Room:
• Simulation Videos
• FHWA Alternative Intersections Video
• Interactive Exhibit
2

3. 3
Project Status
(Items in Orange are Complete, Blue are Ongoing)
• Reconstruct I-66/Route 15 interchange as a Diverging
Diamond Interchange (DDI)
• Replace Route 15 bridges over I-66
• Retaining walls, shared-use path, partial interchange
lighting, fencing, and architectural treatments
• Geometric and access management improvements to
ramps, intersections, Route 55, and frontage road
• Provide drainage and stormwater management facilities
• Replace/modify traffic signals, signs and sign structures,
and guardrail/barrier
• Construct a sound barrier Wall
• Landscaping (will be completed under separate contract)

4. Opening the DDI Configuration
• Close interchange and detour traffic starting 8 p.m.
Friday, Jan. 6 (or Jan. 13, weather depending), to place
final pavement markings
• Route 15 closed from south of Heathcote Blvd to north
of Route 55/Washington St
• Ramps to and from I-66 will also be closed
• Local traffic will be detoured to Old Carolina Rd/
Jefferson St
• Interstate traffic use Route 29 in Gainesville
• Open DDI to traffic by 9 a.m. Saturday, Jan. 7 (or Jan. 14)
• All ramps to and from the Interstate 66
• Two lanes in each direction on Route 15
4

5. Detour – Night of Jan. 6 (or Jan. 13)
5

6. 6
Diverging Diamond Interchange
Traffic Flow

7. 7
Diverging Diamond Interchange
Traffic Flow

8. 8
Project Schedule
Contract awarded May 2014
Public information meeting October 2014
Began right-of-way acquisition Winter 2014
Began construction Spring Fall 2015*
Open DDI configuration January 2017
Project completion Fall Summer 2017
* Project construction is approximately 70% complete.

9. 9
Project Costs
Preliminary engineering: $3 Million
Right-of-way acquisition and
relocation assistance: $8 Million
Design/Build contract (final design,
utility relocation, and construction),
Contingency and VDOT oversight: $48 Million
Total cost: $59 Million
The above estimate has remain unchanged since October 2014.
The project is fully funded by state and federal funds.

10. Stations Around the Room
• VISSIM simulation videos
• Based on actual design for DDI in Haymarket
• Shows future 2036 traffic volumes, AM and PM peaks
• FHWA Alternative Intersections Video – “As
easy as 1-2-3”:
• To Turn Left – Stay to the Left
• To Turn Right – Stay to the Right
• No Turns at Crossover Intersections – Go “Straight”
• Interactive exhibit
• Attendees are invited to “walk” through the DDI exhibit
the way they would drive through one
10

11. 11

12. 12
For More Information…
http://www.virginiadot.org/projects/northernvirginia/i-
66_and_route_15_interchange.asp
OR:
• Visit www.virginiadot.org
• Click on “Projects and Studies” in the orange bar
• Click on the “Northern Virginia” portion of the map
• Scroll to “Under Construction” and look for “I-66 and
Route 15 Interchange Reconstruction” link
Project Manager: Christiana Briganti-Dunn, P.E., CCM
Phone: 703-259-2960
E-mail: Christiana.Briganti@vdot.virginia.gov

13. Traffic Comparison to VDOT’s 1st DDI
180 270
120
0
120
450 310
300 90
700 180
60
0
160
Zion Crossroads DDI
1500
670
1110
720
I-64 WB
Off-Ramp
I-64 WB
On-Ramp
I-64 EB
On-Ramp
I-64 EB
Off-Ramp
US Route 15
I-64
2010 AM Peak
40 1160
320
0
200
40 600
580 780
510 810
130
0
100
Haymarket DDI
570
1520
1010
2880
I-66 WB
Off-Ramp
I-66 WB
On-Ramp
I-66 EB
On-Ramp
I-66 EB
Off-Ramp
US Route 15
I-66
2011 AM Peak

14. 80 530
140
0
140
150 480
550 120
440 150
190
0
350
Zion Crossroads DDI
1070
1720
1120
1450
I-64 WB
Off-Ramp
I-64 WB
On-Ramp
I-64 EB
On-Ramp
I-64 EB
Off-Ramp
US Route 15
I-64
2010 PM Peak
110 1010
740
0
880
140 580
1510 380
680 310
40
0
50
Haymarket DDI
1130
740
2500
1340
I-66 WB
Off-Ramp
I-66 WB
On-Ramp
I-66 EB
On-Ramp
I-66 EB
Off-Ramp
US Route 15
I-66
2011 PM Peak
Traffic Comparison to VDOT’s 1st DDI

15. How Haymarket DDI differs from
Zion Crossroads DDI
15
Triple Left
Dual Left
3 Lanes NB/SB
Single
Right
Spur Ramp to H