1. Slugging in the I-395 Corridor
Jonathan Avner, and Li Li (WRA)
Amanda Baxter, Virginia Department of Transportation
15th TRB National Transportation Planning Applications Conference
Raleigh, NC
May 15, 2017

2. Agenda
Project
Challenge
Options Evaluated
Approach
Findings

3. Project
Development of Traffic Forecasts to support the Environmental Assessment and Interchange Justification Report
I-395 study area extends from north of Edsall Road to Eads Street interchange (near the Pentagon)
Three / four general purpose lanes per direction
Two barrier-separated reversible HOV-3 lanes
Use of MWCOG Model to generate trip tables for Meso and Micro simulations

4. Project
Convert the two existing reversible HOV-3 lanes on I-395 to three managed lanes for eight miles from north of Edsall Road to the vicinity of Eads Street near the Pentagon

5. Challenge
Users of the HOV3 Lane concerned how project will impact them, specifically users of the informal ride sharing, or Slugging
SOV drivers become HOV3 -> Use of the HOV3 system AND toll free users in the build scenario
Definitions
Sluggers:
Scrapers:
The construction of the HOV lanes on the I-395 corridor began the phenomena
Mutual Benefits
Become HOV3 traveler
Save time over transit
Implications to the roadway system

6. Challenge As part of the I-395 HOT Lane Conversion project
Analysis of traffic on the corridor including users of the HOV3 and HOT system
Study of several design alternatives at the Pentagon and other interchanges along the corridor that increased access to the HOV3 /HOT facility is important

7. Options Evaluated
Demand for slugging on the I-395 based on surveys conducted as part of the Pentagon Transportation Management Plan

8. Options Evaluated
From Pentagon TMP 1240 vehicles leaving in the PM peak period
MWCOG Model does not capture the conversion of trips from SOV to HOV3 or the transfer of trips from transit to passenger mode
Significant volume (400 vehicles per hour) entering and leaving the facility
Generate trip tables from MWCOG Model
Mode choice / full model refinement
Identification of SOV candidate trips / conversion to HOV3

9. Approach
MWCOG Model was utilized to create the inputs for the Operational Analysis and Environmental Studies
Creation of an assignment post processor
Align demand with operating periods of the facility
Improved demand estimation for operational analysis

10. Approach

11. Approach Identification of Scraper Trips
Identified slugging locations along corridor based on reported stops
Used select link analysis in PM to identify candidate SOV trips passing by Pentagon and going to destinations
Compared model trips to survey
< Survey: adjusted upto survey
> Survey: took proportion
Converted SOV trip:
SOV / HOV3 / SOV

12. Approach Assumptions Based on 2010 survey demand
Held constant for 2020 and 2040 scenarios
No growth in employment at the Pentagon
AM versus flow of the PM
Location
Vehicles
Passengers
Burke / Springfield
130
275
Horner Road / Potomac Mills
315
600
Montclair / Route 234
245
480
Rt. 17 Stafford
165
320
Rt. 3 Fredericksburg Gordan Road 45 90
Rt. 610 Mine Road
250
Rt. 610 Stafford
Tackett’s Mill / Lorton / VRE
115

13. Findings Scenario analysis Report 2015 (w and w/o)
2040 no build (w and w/o)
2040 build (w and w/o)
Report
Managed lane traffic
Volumes entering Pentagon

14. Findings Results of the scenario analysis
Marginal difference to the overall traffic in the corridor
Shifting of traffic from general purpose to managed facility
Impact at the localized location
Pentagon
Park and Ride Locations

15. Findings
2015
2040 NB

16. Findings
2015
2040 NB

17. Findings
2040 BD
2040 NB

18. Findings
2040 BD
2040 NB

19. Next Steps
Need to consider the use of informal ride sharing into mode choice for models where a prevalent mode and become more common
Working with VDOT on an update to the Fredericksburg MPO Model
Including Slugging as mode

20. Jonathan Avner javner@wrallp.com
Questions
Jonathan Avner
Amanda Baxter
Li Li