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Southern California Ozone Study MOBILE SOURCE IMPROVEMENTS. Ed Yotter Planning & Technical Support Division California Air Resources Board Sacramento, CA. Southern California Ozone Study TRAVEL DEMAND MODELING. Travel Demand Modeling (TDM) What is a TDM? Previous SCAG TDM Current SCAG TDM
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Southern California Ozone StudyMOBILE SOURCE IMPROVEMENTS Ed Yotter Planning & Technical Support Division California Air Resources Board Sacramento, CA
Southern California Ozone StudyTRAVEL DEMAND MODELING • Travel Demand Modeling (TDM) • What is a TDM? • Previous SCAG TDM • Current SCAG TDM • Heavy Duty Truck TDM • Direct Travel Impact Model (DTIM4) • Day Specific Mobile Source Activity • EMFAC2000
Southern California Ozone StudyTRAVEL DEMAND MODELING • What is a TDM? • Estimates Personal Travel Generation • Socio-Economic Data • Home Interview Travel Diaries • Person Trip Distribution • Mode Choice (Walk, auto, bus, etc) • Auto Assignment • Network Link Volumes • Trip-end Activity
Southern California Ozone StudyTRAVEL DEMAND MODELING - Generation • Southern California Association of Governments (SCAG) • Modeling Study Area • Traffic Analysis Zone System • Socio-Economic Data • Population • Housing / Income • Employment • Network
Southern California Ozone StudyTRAVEL DEMAND MODELING - STUDY AREA
Southern California Ozone StudyTRAVEL DEMAND MODELING - TAZs
Southern California Ozone StudyTRAVEL DEMAND MODELING - NETWORK
Southern California Ozone StudyTRAVEL DEMAND MODELING - Socio-Economic Data { Population }
Southern California Ozone StudyTRAVEL DEMAND MODELING - Socio-Economic Data { Household Income }
Southern California Ozone StudyTRAVEL DEMAND MODELING - Socio-Economic Data { Employment }
Southern California Ozone StudyTRAVEL DEMAND MODELING - Distribution • DISTRIBUTION • Productions & Attractions • Peak Periods • Off-Peak Periods • By Trip Purpose • Trip Purpose (Home-based, Non-home based) • Examples: • Home-based Work • Home-based Shop • Home-based School • Work to Other • etc
Southern California Ozone StudyTRAVEL DEMAND MODELING - Mode Choice • MODE CHOICE • Non-Motorized (Walk / Bicycle) • Automobile • Driver • Passenger • Transit • Bus • Rail
Southern California Ozone StudyTRAVEL DEMAND MODELING - Assignment • ASSIGNMENT • Feedback Loops • Realistic Travel Times and Costs • Mode Choice (auto, bus, rail, etc) • Validation of Results • Volumes • Time of Day • Travel Time • Screenline Validation
Southern California Ozone StudyTRAVEL DEMAND MODELING - SCREENLINES
Southern California Ozone StudyHEAVY DUTY TRUCK MODEL • GENERATION • S/E Data • Commodity Flow Database (STCC) • Inbound Flows • Outbound Flows • Special Generators (Airports & Seaports) • HDT Classes • Light-heavy (8,500 to 14,000 GVW) • Medium-heavy (14,000 to 33,000 GVW) • Heavy-heavy (over 33,000 GVW)
Southern California Ozone StudyHEAVY DUTY TRUCK MODEL • GENERATION (continued) • Outbound truckload • Private truck mode • Less-than-truckload • By STCC • By HDT vehicle class • Time of day
Southern California Ozone StudyHEAVY DUTY TRUCK MODEL • DISTRIBUTION • Truck Trip • External Truck Trips (X-I & I-X) • Internal Truck Trips (I-I) • Through Truck Trips (X-X) • Time Period • Morning Peak (6am - 9am) • Mid-day (9am - 3pm) • Evening Peak (3pm - 7pm) • Night (7pm - 6am)
Southern California Ozone StudyHEAVY DUTY TRUCK MODEL • ASSIGNMENT • Special Considerations • Truck Prohibitions (e.g. Pasadena Freeway) • Significant Grades • Passenger Car Equivalents (PCE) • Example: 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 • Congestion Adjustments (as much as 34% increase)
Southern California Ozone StudyCOMBINED TRAVEL DEMAND MODELS • COMBINED MODEL ASSIGNMENT • Auto Assignment • Heavy-duty Truck Assignment • with PCE & Congestion Adjustments • Final Network Loading • Realistic Speeds on Links • Improved Volume Estimates • Screenline Validation
Southern California Ozone StudyDIRECT 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 • METEOROLOGY • GRIDDED DAY SPECIFIC TEMPERATURES & RELATIVE HUMIDITY DIRECT TRAVEL IMPACT MODEL • USER PROGRAM CONTROLS • GRIDDED AREA • NETWORK TO GRID TRANSFORMATION • STARTS/PARKS/STABLES FACTORS FROM PERIOD • TO HOUR • GRIDDED MOTOR VEHICLE EMISSIONS • HOUR OF THE DAY • POLLUTANT • PROCESS