1. Southern California Ozone Study MOBILE SOURCE IMPROVEMENTS Ed Yotter Planning & Technical Support Division California Air Resources Board Sacramento, CA

2. Southern California Ozone Study TRAVEL DEMAND MODELING zTravel Demand Modeling (TDM) yWhat is a TDM? yPrevious SCAG TDM yCurrent SCAG TDM yHeavy Duty Truck TDM zDirect Travel Impact Model (DTIM4) zDay Specific Mobile Source Activity zEMFAC2000

3. Southern California Ozone Study TRAVEL DEMAND MODELING zWhat is a TDM? yEstimates Personal Travel Generation xSocio-Economic Data xHome Interview Travel Diaries yPerson Trip Distribution yMode Choice (Walk, auto, bus, etc) yAuto Assignment zNetwork Link Volumes zTrip-end Activity

4. Southern California Ozone Study TRAVEL DEMAND MODELING - Generation zSouthern California Association of Governments (SCAG) yModeling Study Area yTraffic Analysis Zone System ySocio-Economic Data xPopulation xHousing / Income xEmployment yNetwork

5. Southern California Ozone Study TRAVEL DEMAND MODELING - STUDY AREA

6. Southern California Ozone Study TRAVEL DEMAND MODELING - TAZs

7. Southern California Ozone Study TRAVEL DEMAND MODELING - NETWORK

8. Southern California Ozone Study TRAVEL DEMAND MODELING - Socio-Economic Data { Population }

9. Southern California Ozone Study TRAVEL DEMAND MODELING - Socio-Economic Data { Household Income }

10. Southern California Ozone Study TRAVEL DEMAND MODELING - Socio-Economic Data { Employment }

11. Southern California Ozone Study TRAVEL DEMAND MODELING - Distribution zDISTRIBUTION yProductions & Attractions xPeak Periods xOff-Peak Periods xBy Trip Purpose yTrip Purpose (Home-based, Non-home based) xExamples: Home-based Work Home-based Shop Home-based School Work to Other etc

12. Southern California Ozone Study TRAVEL DEMAND MODELING - Mode Choice zMODE CHOICE yNon-Motorized (Walk / Bicycle) yAutomobile xDriver xPassenger yTransit xBus xRail

13. Southern California Ozone Study TRAVEL DEMAND MODELING - Assignment zASSIGNMENT yFeedback Loops xRealistic Travel Times and Costs xMode Choice (auto, bus, rail, etc) yValidation of Results xVolumes xTime of Day xTravel Time yScreenline Validation

14. Southern California Ozone Study TRAVEL DEMAND MODELING - SCREENLINES

15. Southern California Ozone Study HEAVY DUTY TRUCK MODEL zGENERATION yS/E Data xCommodity Flow Database (STCC) Inbound Flows Outbound Flows xSpecial Generators (Airports & Seaports) yHDT Classes xLight-heavy (8,500 to 14,000 GVW) xMedium-heavy (14,000 to 33,000 GVW) xHeavy-heavy (over 33,000 GVW)

16. Southern California Ozone Study HEAVY DUTY TRUCK MODEL zGENERATION (continued) xOutbound truckload xPrivate truck mode xLess-than-truckload By STCC By HDT vehicle class xTime of day

17. Southern California Ozone Study HEAVY DUTY TRUCK MODEL zDISTRIBUTION yTruck Trip xExternal Truck Trips (X-I & I-X) xInternal Truck Trips (I-I) xThrough Truck Trips (X-X) yTime Period xMorning Peak (6am - 9am) xMid-day (9am - 3pm) xEvening Peak (3pm - 7pm) xNight (7pm - 6am)

18. Southern California Ozone Study HEAVY DUTY TRUCK MODEL zASSIGNMENT ySpecial Considerations xTruck Prohibitions (e.g. Pasadena Freeway) xSignificant Grades yPassenger Car Equivalents (PCE) xExample: 5-10% Trucks, 3% Grade, Length > 1 mile Light-heavy duty truck = 4.2 passenger cars Medium-heavy duty truck = 5.9 passenger cars Heavy-heavy duty truck = 7.8 passenger cars xCongestion Adjustments (as much as 34% increase)

19. Southern California Ozone Study COMBINED TRAVEL DEMAND MODELS zCOMBINED MODEL ASSIGNMENT yAuto Assignment yHeavy-duty Truck Assignment xwith PCE & Congestion Adjustments yFinal Network Loading xRealistic Speeds on Links xImproved Volume Estimates xScreenline Validation

20. Southern California Ozone Study DIRECT TRAVEL IMPACT MODEL (DTIM) TRAVEL DEMAND MODEL  LINK VOLUMES & SPEEDS  TRIP-END DATA  NETWORK DESCRIPTION BY TIME PERIOD EMFAC2000  CALENDAR YEAR & SEASON  COMPOSITE EMISSION RATES BY VEHICLE CLASS BY TEMPERATURE & RELATIVE HUMIDITY, BY SPEED USER PROGRAM CONTROLS  GRIDDED AREA  NETWORK TO GRID TRANSFORMATION  STARTS/PARKS/STABLES FACTORS FROM PERIOD TO HOUR METEOROLOGY  GRIDDED DAY SPECIFIC TEMPERATURES & RELATIVE HUMIDITY DIRECT TRAVEL IMPACT MODEL GRIDDED MOTOR VEHICLE EMISSIONS  HOUR OF THE DAY  POLLUTANT  PROCESS

21. Southern California Ozone Study DTIM - GRIDDED EMISSIONS