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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

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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

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Project Background

• Arterial Transitway Corridors Studycompleted April 2012

• Snelling Avenue top priority

• 1st BRT to be operated by Metro Transit

St. Paul

Minneapolis

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10 Miles4 Cities20 stations2 LRT connections

Blue Line LRT

Green Line LRT

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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