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SUZANNE CHILDRESS, ERIK SABINA, DAVID KURTH, TOM ROSSI, JENNIFER MALM DRCOG Focus Activity-Based Model Calibration/Validation Innovations in Travel Modeling.

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Presentation on theme: "SUZANNE CHILDRESS, ERIK SABINA, DAVID KURTH, TOM ROSSI, JENNIFER MALM DRCOG Focus Activity-Based Model Calibration/Validation Innovations in Travel Modeling."— Presentation transcript:

1 SUZANNE CHILDRESS, ERIK SABINA, DAVID KURTH, TOM ROSSI, JENNIFER MALM DRCOG Focus Activity-Based Model Calibration/Validation Innovations in Travel Modeling Conference May 12, 2010

2 Focus Model Flow Population Synthesizer Highway and Transit Skimming Regular Workplace Location Regular School Location Auto Availability Daily Activity Pattern/Exact Number of Tours Tour Primary Destination Choice Tour Mode Choice Tour Time of Day Choice Intermediate Stop Generation Intermediate Stop Location Trip Mode Choice Trip Time of Day Highway and Transit Assignment (Simplified)

3 Model Estimation Data: 1997 Travel Behavior Inventory (TBI) Next Steps: 1997 Validation Calibrated to Forecast Extensive Model Calibration/Validation Plan What’s the plan?

4 Data Sources 1997 TBI 2000 CTPP Other 2000 Census 2005 ACS 2005 State Demo- grapher 2005 Traffic/ Transit Counts 2005 HPMS VMT

5 Location Data At Point Level

6 Run component. Compare to observed Good? No. Identify source Software? Earlier Component? Input Data? Estimation? Utility Function? Test Logit in Spreadsheet No Discernable Problem Adjust Parameters Disaggregate Until You find the Problem Yes! Next Component Go back.

7 Process Example: Vehicle Availability Household Choice 0 Vehicles1 Vehicles2 Vehicles 3+ Vehicles

8 Utility Function Example (simplified) Utility (No Vehicle) = * 1 HH Driver * 2 HH Drivers * 3 HH Drivers * 4+ HH Drivers * (Cars >= Workers?) * (HH income < $15k/year?) * (HH income between $15k/year - $30k/year?) * (HH income between $75k/year - $100k/year?) * (HH income > $100k/year) * Transit Accessibility

9 Vehicle Availability - NO Calibration Household Vehicles 2005 Model 2005 ACS 2000 Census 0 vehicles 4%7%6% 1 vehicles 30%33% 2 vehicles 42%40%41% 3+ vehicles 25%19%20% Regional Households by Number of Vehicles:

10 Disaggregate–Where is Problem the Worst? Household Vehicles AdamsArapahoeBoulderDenverDouglas Jefferson 0 vehicles3% 6%1%2% 1 vehicle26%29% 39%17%27% 2 vehicles42% 43%35%53%44% 3+ vehicles28%25% 20%29%27% Household Vehicles AdamsArapahoeBoulderDenverDouglas Jefferson 0 vehicles4%5%4%12%1%4% 1 vehicle32%34%29%43%20%32% 2 vehicles41% 46%33%55%41% 3+ vehicles23%20%21%12%24%23% 2005 Model: Households by County by Vehicle Availability 2005 ACS: Households by County by Vehicle Availability

11 Set Up Logit Model in a Spreadsheet (simplified) ALTERNATIVENo Car 1 Car2 Car 3 Car4+ Car Variable NameCoeffTermCoeffTermCoeffTermCoeffTermCoeffTerm 1 driver in HH drivers in HH drivers in HH drivers in HH HH inc under $15k/yr HH inc $15k-30k/yr HH inc $75k-100k/yr HH inc above $100k/yr Transit Accessibilitiy UTILITY EXP(Utility) Sum of EXP(Utility) 6.9 Probability4.6% 89.3% 5.1% 0.8% 0.1%

12 Get Your Software to Write Out All Coefficients, Variable Values, and Utilities :08:37,098 DEBUG 5268 IRMCommon.UtilityFunctionTerm - Constant Value is :08:37,098 DEBUG 5268 IRMCommon.UtilityFunction - Running Utility Sum is :08:37,098 DEBUG 5268 IRMCommon.UtilityFunctionTerm - Coefficient is 1.18, Variable Name is PersTypeUniversity, Variable Value is :08:37,098 DEBUG 5268 IRMCommon.UtilityFunction - Running Utility Sum is

13 Final Changes Changed Coefficient for Transit Accessibility from to 8.0 in 0 car alternative Added Constant 0.3 to 0 car alternative

14 Auto Availability Model Calibrated–5 th Run Household Vehicles 2005 Model 2005 ACS 2000 Census 0 autos 6% 7%6% 1 autos 27% 33% 2 autos 41% 40%41% 3+ autos 26% 19%20% Regional Households by Number of Autos

15 Auto Availability Model Calibrated–5 th Run Household Vehicles AdamsArapahoeBoulderDenverDouglas Jefferson 0 vehicles6%7%5%9%2%4% 1 vehicle25%22%27%36%16%26% 2 vehicles42%38%46%35%53%44% 3+ vehicles28%33%22%20%29%26% Household Vehicles AdamsArapahoeBoulderDenverDouglas Jefferson 0 vehicles4%5%4%12%1%4% 1 vehicle32%34%29%43%20%32% 2 vehicles41% 46%33%55%41% 3+ vehicles23%20%21%12%24%23% 2005 Model: Households by County by Vehicle Availability 2005 ACS: Households by County by Vehicle Availability

16 Final Thoughts Make a plan –  How good does the model have to be?  By when?  For what purpose? Be creative in comparison –  For data sources and summaries.  Look at as much as possible. Break the problem down until the source is revealed. Do an alternate year run –  May reveal other issues with calibration.  Important for validation.

17 Person Trips By Mode

18 Average Tours per Person per Day By Tour Purpose

19 Trips By Time of Day

20 Modeled Versus Observed VMT # Links With Counts Modeled VMT With Counts Actual VMT With Counts %Error 1,68321,166,00020,507,0003.2% Total VMT by Facility Type Facility Type #Links Modeled VMT % Modeled VMT Actual VMT % Actual VMT Difference of Percents Freeway2108,791,00042%9,605,00047%-8% Major Regional Arterial711,834,0009%1,587,0008%16% Principal Arterial8638,990,00043%7,452,00036%21% Minor Arterial3161,121,0005%1,279,0006%-12% Collector218406,0002%558,0003%-27%

21 VMT by Screenline ScreenlineLinks with Counts Total Observed VMT on Links with Counts Modeled Volume on Links with countsPercent Error 120Th10 247, ,34613% CastleRock2 59,520 75,74227% Colfax16 405, ,47412% ColoradoBlvd10 419, ,6519% DIA3 100,862 80,711-20% DowntownCir19 423, ,1125% Hampden10 504, ,1162% Kipling9 188, ,21414% TowerRd5 64,603 37,195-42% Wadsworth20 581, ,7361%

22 Transit trips by sub-mode Submode2005 Observed2005 Modeled Difference: Observed- Modeled Mall Shuttle47,27656,606-9,330 Denver Local123,821172,231-48,410 Denver Limited17,49719,943-2,446 Boulder Local19,21021,983-2,773 Longmont Local6892,385-1,696 Express10,74124,737-13,996 Regional11,3559,9721,383 skyRide5, ,579 Light Rail34,57844,689-10,111 Total270,288353,088-82,800


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