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Using VISSIM to Evaluate BRT Station Configurations and TSP using ASC/3
Controllers
Scott Poska, P.E., PTOE2013 PTV Users Group Meeting
October 2, 2013
2
Outline
• Project Background• Project Goals• Study Methodology• VISSIM Model• ASC/3 Controller Module• Station Configuration Evaluations & Results• TSP Evaluation & Results• Bus Following Video• Project Conclusions• VISSIM Lessons Learned
3
Project Background
• Arterial Transitway Corridors Studycompleted April 2012
• Snelling Avenue top priority
• 1st BRT to be operated by Metro Transit
St. Paul
Minneapolis
4
10 Miles4 Cities20 stations2 LRT connections
Blue Line LRT
Green Line LRT
5
BRT “Rapid Bus” Components
• Platform fare collection
• Half-mile station spacing
• Stops in travel lane
• 2 Doors
• Transit Signal Priority
Illustration of a Rapid Bus stop in the travel lane
Project Goals:
1. Evaluate mainline traffic impact of station locations
2. Assess potential benefit of Transit Signal Priority
Project Goals
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Study Methodology
• VISSIM
• Scenarios Modeled
• AM/PM Peaks
No. Scenario Name1. Baseline2. Rapid Bus Alpha3. Rapid Bus Beta4. Rapid Bus Refined5. Rapid Bus Refined with TSP
Traffic Impact
TSP Benefit
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VISSIM Model
• 10 miles long• 34 signalized intersections• Existing geometry & volumes• Mix of existing/proposed signal timing• Included 1 of 2 crossing LRT lines
Minnehaha
Co Rd BHar MarRoselawnLarpenteurHoytMidwayHewitt
Thomas
Spruce TreeSt. AnthonyConcordia
Fairview
Kenneth
Cleveland
Finn
45th/46th
Hiawatha
Minnehaha
Co Rd B2 East RampsCo Rd B2 West Ramps
University
MarshallSelby
SummitGrand
St. Clair
Jefferson
Randolph
Highland
Ford
Cretin
42nd
36th
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• Challenge– Code & calibrate model of
this size!
• Solution– Links/Connectors– Split network elements up– Use video from counts to
calibrate
•Model statistics– 1200 links and connectors– 5100 static routes– ~30 min run time
VISSIM Model
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Econolite ASC/3 Controller Module
• ASC/3 controller module for all 34 signals
• Challenge– No module operation documentation
• Solution:– Interface identical to Virtual
Controller/Aries– Interchangeable ASC/3 databases
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Rapid Bus Station Configurations
• 3 station configurations
• 75% farside
• Occupancy varies along route
• 10 min. headways
• 7-21 sec. dwell times
BumpoutStop in Travel Lane;
Replace existing on-street parking
Stop in Travel Lane Stop in Bus-Only Shoulder
Curbside
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Station Configuration Evaluations
• Challenge– What VISSIM Evaluation to
Measure Station Traffic Impacts?
• Solution– Test evaluations on small
network• Node• Link• Travel Time
Dwell Time (sec) 7 21 300
WBR (140 veh) 20.8 19.0 27.3NBT (1535 veh) 18.6 19.0 48.3EBL (110 veh) 40.7 43.5 39.0Intersection 19.4 19.1 32.4
Adjacent Link 31.0 30.9 29.8Upstrean Link 19.0 18.7 11.6
1305' Segment 45.1 46.9 76.2
Node Evaluation (sec/veh)
Link Evaluation (mph)
Travel Time Evaluation (sec)
Farside Station Evaluation Test
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Results: Q1 - Traffic Impact
• MOEs:– Travel Time– Vehicle-delay /
Level of Service
• Baseline vs. Alpha– AM Peak Hour
• No impact (<2 sec./veh.)– PM Peak Hour
• University• Hague Minnehaha
45th/46th
Woodlawn
Finn
Kenneth
Fairview
Highland
Randolph
St. Clair
Grand
Hague
University
Minnehaha
Hewitt
Larpenteur
Roselawn
Cty. B/Har Mar
0 10 20 30 40 50 60 70 80 90 100
Baseline vs. Alpha Non-Rapid Bus Travel TimeNorthbound - PM Peak Hour
BaselineAlpha
4-Block Travel Time (sec.)
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Results: Q1 - Traffic Impact
• Alpha vs. Beta: NB University
University
Spruce Tree
Snel
ling
Alpha
Beta
Scenario Platform Type
Rapid Bus Alpha Farside + Bumpout(stop in travel lane)
Rapid Bus Beta Nearside + Curbside(stop in right turn lane)
Northbound0
10
20
30
40
50
60
70
80
90
100
79.9
89.4
78.2
Travel Time
BaselineAlphaBeta
4-Bl
ock
Trav
el T
ime
(sec
.)
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TSP Assumptions
• Unconditional• LRT vs. BRT:
first-come, first served• Max green reduction:
– 25% of split or– To phase minimum
• ASC/3 defaults:– Early + extended
green– No skipping/omitting
phases (incl. peds)
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TSP Setup in VISSIM
• Rapid Bus Detectors
• Placed 20 seconds in advance
• Placement adjusted for near-side stops
• ASC/3 mapper to assign TSP detector numbers
• Locking detection issue
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Results: Q2 - TSP
• Network-wide:– 10-14% travel
time reduction for Rapid Bus
NB SB NB SBAM PM
0
5
10
15
20
25
30
35
40
45
35 34
40
37
31 31
3533
Rapid Bus Travel Time
No TSPWith TSP
Trav
el T
ime
(min
.)
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Bus Following Video
• Client Requests– “Bus Following” Videos– “Play by Play” of
Signal Controller TSP Status • Challenge
– “Bus Following” Keyframes– Record ASC/3 Controller TSP status
• Solution– Manually note times bus changes motion– Manually note times of controller changes
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Project Conclusions
• No Station Impacts (AM Peak)• 2 Stations with Impacts (PM Peak)• Rapid Bus TSP Savings of 3-5 minutes (10-14%)
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VISSIM Lessons Learned
• Model Size– Merge work frequently– Vehicle Classes– Text Editor for mass edits
• ASC/3 Controller Module– TOD schedule & model time– 4 digit filename– Locking detection for TSP
• Evaluations– Travel Time evaluation is simplest & most flexible– Travel Time start/end locations
• Bus Following Video• Note times and seed number• No rewind!
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Acknowledgement
• Thank you to Katie Roth with Metro Transit for managing this successful project!
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Contact
Scott Poska, P.E., PTOESRF Consulting Group, Inc.sposka@srfconsulting.com
www.srfconsulting.com763-475-0010
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