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SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY San Francisco DTA Model: Working Model Calibration Part 1: Process Greg Erhardt Dan Tischler Neema Nassir DTA Peer Review Panel Meeting July 25 th , 2012

DTA Peer Review Panel Meeting July 25 th , 2012

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San Francisco DTA Model: Working Model Calibration Part 1: Process Greg Erhardt Dan Tischler Neema Nassir. DTA Peer Review Panel Meeting July 25 th , 2012. Agenda. 9:00Background 9:30Technical Overview – Part 1 Development Process and Code Base/Network Development 10:15Break - PowerPoint PPT Presentation

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Page 1: DTA Peer Review Panel Meeting July 25 th , 2012

SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY

San Francisco DTA Model: Working Model Calibration

Part 1: Process

Greg ErhardtDan Tischler

Neema Nassir

DTA Peer Review Panel MeetingJuly 25th, 2012

Page 2: DTA Peer Review Panel Meeting July 25 th , 2012

SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY

Agenda

• 9:00 Background• 9:30 Technical Overview – Part 1

• Development Process and Code Base/Network Development

• 10:15 Break• 10:30 Technical Overview – Part 2

• Calibration and Integration Strategies

• 12:00 Working Lunch / Discussion• 2:00 Panel Caucus (closed)• 3:30 Panel report• 5:30 Adjourn

Page 3: DTA Peer Review Panel Meeting July 25 th , 2012

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Outline

• Model Overview• Calibration Approach• Speed Flow Parameters

• Presented by Dan Tischler & Neema Nassir

• Model Calibration Runs• Current Model Parameters• Key Findings

Page 4: DTA Peer Review Panel Meeting July 25 th , 2012

Model Overview

Page 5: DTA Peer Review Panel Meeting July 25 th , 2012

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Model Overview

• Natural breakpoint at San Bruno Mountain Park• 976 TAZs• 22 external stations• 1,115 signals• 3,726 stop controlled intersections

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Model Overview

• PM Peak Model from 4:30-6:30 pm• 1 hour warm-up time• 3 hour network clearing time• 270,000 internal trips• 180,000 IX , XI or XX trips Dynameq Software

Platform

Page 7: DTA Peer Review Panel Meeting July 25 th , 2012

Calibration Approach

Page 8: DTA Peer Review Panel Meeting July 25 th , 2012

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Calibration Approach

1. Ensure quality inputs2. Measure anything that can be

measured3. Evaluate the results qualitatively4. Evaluate the results quantitatively5. Make defensible adjustments

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Ensure Quality Inputs• Identify and investigate failed signal imports• Spot check stop-control—some issues with direction of 2-way stops• Automate as much as possible

DESCRIPTION:

NOTES:

S M T W T F S

to -- X X X X X --to -- X X X X X --

X X X X X X X

PHASE 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

2 G Y R

6 G Y R

8 R G Y R

2P W FRH RH

6P W FRH RH

4P RH W FRH RH

8P RH W FRH RH

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

12.0 12.0 3.5 0.5 18.0 10.0 3.5 0.512.0 12.0 3.5 0.5 18.0 10.0 3.5 0.512.0 12.0 3.5 0.5 18.0 10.0 3.5 0.5

X = YES -- = NO

Mission St EB

ALL OTHER TIMES

18:30

CYCLE

212313

(seconds)

STREET

Mission St WB

Peds Xing 09th St SS

Peds Xing 09th St NS

09th St and Mission St

CH

AN

GE

60.0

10:00

60.0

Peds Xing Mission WS

09th St NB

OFFSET(seconds)

Peds Xing Mission ES

60.0

CSO

111

--1

1

6:0015:00

FLASHOFFSET

----

23

1

SPLIT 11

2

CYCLE

3

Controller:CabinetOperation Date:System:Master:Cascade:

2070M-SF

2/29/19562,6

STREET NAMEMission09th St8

Soma (TBC)5th/How ard

FLASHRR

09th St and Mission St

32

New cycle lengths, made part of SOMA system

24313000

10:2003/01/2006

PHASE

PN/JD

32

CHANGEIntersection No.ENGINEER:

Electrician

SIGNAL INTERVALS (seconds)

R.Olea

202020

OPERATION TIMESPLAN ONE (1)

Time:Date:

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Measure Anything that can be Measured• Measure speed flow parameters• Change perceived cost instead of measured speed and capacity• Avoid arbitrary demand changes

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Evaluate Qualitatively

Example of extreme congestion

Page 12: DTA Peer Review Panel Meeting July 25 th , 2012

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Evaluate Quantitatively

• Relative gap, RMSE, GEH, R-Squared• Scatter plots, maps• Tables by: area type, facility type, speed, turn type, time period, etc. • Corridor plots• Speeds

Page 13: DTA Peer Review Panel Meeting July 25 th , 2012

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Make Defensible Adjustments

• Evaluate results and investigate worse offenders• Hypothesize problems and propose changes20 Worst Links with Volumes too Low

LinkID Label FacilityType FreeflowSpeed NumLanes StartTime EndTime CountVolume ModelVolume Diff15034 HARRISON ST 4 30 5 17:00:00 18:00:00 2093 368 -172513221 SUNSET BLVD 4 35 3 17:00:00 18:00:00 2514 884 -163013221 SUNSET BLVD 4 35 3 16:00:00 17:00:00 2248 961 -128713223 SUNSET BLVD 4 35 3 17:00:00 18:00:00 2204 926 -127832848 HARRISON ST 4 30 5 17:00:00 18:00:00 1443 186 -125728691 GEARY BLVD 6 30 1 17:00:00 18:00:00 1300 47 -1253

9010899 HARRISON ST 4 30 5 17:00:00 18:00:00 1946 722 -122415034 HARRISON ST 4 30 5 16:00:00 17:00:00 1664 461 -120328691 GEARY BLVD 6 30 1 16:00:00 17:00:00 1264 67 -119716027 HARRISON ST 4 30 5 17:00:00 18:00:00 1900 737 -1163

Page 14: DTA Peer Review Panel Meeting July 25 th , 2012

Speed Flow Parameters

Page 15: DTA Peer Review Panel Meeting July 25 th , 2012

Model Calibration Runs

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Base Case – July 6 Test

Change(s):

Results:

• RMSE: Links = 133 (58%), Movements = 64 (80%)

• GEH: Links = 7.17, Movements = 4.59

• Overall Vol/Count Ratio: Links = 0.6527, Movements = 0.7145

• This test includes intrazonal trips (assigned to the nearest centroid) and ambiguous two-way stop signs re-assigned as all-way stops

• At this stage, there were still network and signal issues that have since been dealt with

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Test 1 – Speed-Flow Curve Changes

Change(s): Free-flow speed, response time factor, effective length factor

Results:

• RMSE: Links = 132 (57%), Movements = 64 (80%)

• GEH: Links = 7.04, Movements = 4.56

• Overall Vol/Count Ratio: Links = 0.6467, Movements = 0.7051

• Increasing RTF and decreasing speeds caused gridlock in the CBD

• Without bus-only lanes, these changes have more impact

• With bus-only lanes included, capacities are too low and CBD is full of gridlock

Page 18: DTA Peer Review Panel Meeting July 25 th , 2012

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Test 2 – Removing Bus-only Lanes:Stockton Street Example

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Test 2 – Removing Bus-only Lanes

Change(s): Bus-only lanes no longer specified as bus-only

Results:

• RMSE: Links = 135 (59%), Movements = 64 (80%)

• GEH: Links = 7.32, Movements = 4.59

• Overall Vol/Count Ratio: Links = 0.6459, Movements = 0.7085

• Got rid of gridlock in CBD

• People are allowed to use these lanes for right turns – how can we model that?

• Need to add them back in some way while still allowing for limited use – next test.

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Test 3 – Increasing Demand

Change(s): Increasing internal demand by 30%

Results:

• RMSE: Links = 155 (68%), Movements = 72 (90%)

• GEH: Links = 8.18, Movements = 4.86

• Overall Vol/Count Ratio: Links = 0.6316, Movements = 0.7526

• Significant gridlock all over the network

• Previously about 30% low on counts, but more demand overloads the network

• Need to fix flow patterns and speeds, not demand

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Test 4 – Penalizing Locals & Collectors

DTA Volumes Static Volumes

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Test 4 – Penalizing Locals & Collectors

DTA Volumes Static Volumes

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Test 4 – Penalizing Locals & Collectors

Change(s): Local and collector links had penalty of 1*FFTime added to generalized cost

Results:

• RMSE: Links = 122 (53%), Movements = 61 (76%)

• GEH: Links = 6.85, Movements = 4.47

• Overall Vol/Count Ratio: Links = 0.8074, Movements = 0.855

• Arterial Plus flows are still much lower than expected – looking at speed-flow curves

• Important to test this again with transit-only lanes added back in some way

Page 24: DTA Peer Review Panel Meeting July 25 th , 2012

Current Model Parameters

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Free Flow Speeds

Free Flow Speed (mph)

Regional Core CBD Urban Biz Urban

Local 25 25 30 30Collector 25 25 30 30Minor Arterial 30 30 35 35Major Arterial 30 30 35 35Super Arterial 30 30 35 35Fwy-Fwy Connect 35 40 45 45Expressway 60 65 65 65Freeway 60 65 65 65

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Response Time Factors

Response Time Factor*

Regional Core CBD Urban Biz Urban

Local 1.2 1.2 1.2 1.2Collector 1.2 1.2 1.2 1.2Minor Arterial 1.2 1.2 1.2 1.2Major Arterial 1.2 1.2 1.2 1.2Super Arterial 1.2 1.2 1.2 1.2Fwy-Fwy Connect 1.2 1.2 1.2 1.2Expressway 1.2 1.2 1.2 1.2Freeway 1.1 1.1 1.1 1.1

* Response times corresponding to RTF equal to 1.1 and 1.2 are respectively 1.375 and 1.5 seconds

Page 27: DTA Peer Review Panel Meeting July 25 th , 2012

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Saturation Flow Rates

Saturation Flow (vphpl)

Regional Core CBD Urban Biz Urban

Local 1671 1671 1760 1760Collector 1671 1671 1760 1760Minor Arterial 1760 1760 1830 1830Major Arterial 1760 1760 1830 1830Super Arterial 1760 1760 1830 1830Fwy-Fwy Connect 1830 1886 1932 1932Expressway 2031 2055 2055 2055Freeway 2185 2213 2213 2213

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Other Traffic Flow Parameters

Effective Length (Ft.) 24Effective Length Factor 1.17Jam density (vpmpl) 220

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Assignment Specification

These values define the period of the simulation: • Start of demand: 15:30 • End of demand: 18:30 • End of simulation period: 21:30 • Transit lines simulation: Yes • Re-optimization: No • Re-optimization iteration(s): 0

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Demand Specification

Demand and generalized cost for cars: • class: Car_NoToll • matrix: car_notoll • paths: 20 • intervals: 12 • types (%): Car=100, • generalized cost: movement expression + link expression• movement expression: ptime+(left_turn_pc*left_turn)+

(right_turn_pc*right_turn) • link expression: fac_type_pen*(3600*length/fspeed)

Demand and generalized cost for trucks: • class: Truck_NoToll • matrix: truck_notoll • paths: 20 • intervals: 12 • types (%): Truck=100, • generalized cost: movement expression + link expression movement

expression: ptime+(left_turn_pc*left_turn)+(right_turn_pc*right_turn) • link expression: fac_type_pen*(3600*length/fspeed)

Page 31: DTA Peer Review Panel Meeting July 25 th , 2012

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Control Plans and Results Specifications

Signals are applied during this period: • excelSignalsToDynameq: 15:30 - 18:30

These settings specify the time steps used by Dynameq. The purpose of these settings is just for analysis of the DTA results and doesn’t have any bearing on the results themselves.

• Simulation results: 15:30:00 - 21:30:00 -- 00:05:00

• Lane queue animation: 15:30:00 - 21:30:00 -- 00:05:00

• Transit results: 15:30:00 - 21:30:00 -- 00:05:00

Page 32: DTA Peer Review Panel Meeting July 25 th , 2012

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Advanced Specifications

These values are settings for the DTA method used by Dynameq.

• Traffic generator: Conditional • Random seed: 1 • Travel times averaged over: 450 s • Path pruning: 0.001 • MSA reset: 3 • Dynamic path search: No • MSA method: Flow Balancing • Effective length factor: 1.00 • Response time factor: 1.00

Page 33: DTA Peer Review Panel Meeting July 25 th , 2012

Key Findings

Page 34: DTA Peer Review Panel Meeting July 25 th , 2012

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Key Findings

• Model is sensitive to changes, and can easily regress into gridlock.

• Bus-only lanes matter.• Penalizing locals and collectors helps. • Increasing internal demand 10% helps.

Increasing demand 30% causes gridlock. • Most runs show less congestion than we

would anticipate.

Page 35: DTA Peer Review Panel Meeting July 25 th , 2012

Questions?