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Ohio Statewide Travel Model: Framework, Freight, and Initial Calibration

Session 6:. Ohio Statewide Travel Model: Framework, Freight, and Initial Calibration. 11th National Transportation Planning Applications Conference May 6-10, 2007, Daytona Beach, Florida. Acknowledgements. This presentation was primarily developed by Pat Costinett. Topics.

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Ohio Statewide Travel Model: Framework, Freight, and Initial Calibration

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  1. Session 6: Ohio Statewide Travel Model:Framework, Freight, and Initial Calibration 11th National Transportation Planning Applications ConferenceMay 6-10, 2007, Daytona Beach, Florida

  2. Acknowledgements This presentation was primarily developed by Pat Costinett.

  3. Topics Ohio Statewide Modeling Framework Micro-simulation Integrates: Economic Land use Transport Models Aggregate Commercial Model (ACOM) Preliminary calibration results

  4. General Model Structure • Integrated micro-simulation based • Model economic activity & land use • Build synthetic population • Tour-based • Home tours • Establishment/Work tours • Aggregate commodity movements

  5. Model Components & Flows

  6. Model Components & Flows Economic Activity by Geography

  7. ISAM • Input-output economic model • Represents trading commodities • Exogenous to the model system

  8. 1 = Model Area

  9. ISAM Input-output economic model Represents trading commodities Exogenous to the model system Region to region commodity flows Shares of commodity flows from the model area to regions

  10. Economic Activity & Land Development Approximately 700 districts and 4000 zones Distribution of economic activities & flows by sector to analysis districts Production of goods & services by zone Consumption demand for goods & services by zone Flows of commodities (goods, services & labor) among zones In response to exchange prices Interacting with a grid-based representation of land supply, develop types, zoning, water & sewer service, flood plains, steep slopes, other protected land uses and land prices

  11. Economic Activity & Land Development Results: Flows of commodities between districts Floor space allocated to activities by zone

  12. Model Components & Flows Transport Models

  13. Types of Trip Making Modeled • Personal Travel /Household Travel (PT): • person movements arising from household (or population) production and consumption, • separated into short distance (50 mi or less) and long distance • Visitor Travel (VM): • person movements made by non-residents staying at locations in the internal model area • Business/Services Travel (DCOM): • movements arising as part of the rest of the ‘business cycle’ apart from the physical delivery of commodities • Goods Transport (ACOM): • shipments of commodities arising from economic activity production and consumption

  14. Commercial Travel • Incorporates long-haul commodity shipment, localized goods delivery, service provision & work-related tours • Long-haul shipment related directly to commodity flows • Establishment survey of goods delivery, service provision & work-related tours • Micro-simulation of commercial tours for each employee (a first at this scale)

  15. Why a freight model? • Need to be consistent with economic models • Freight movements are important to Ohio: • Interest in impact of Turnpike tolls on trucks. • Interest in road-rail diversion. • Relatively large impact on traffic LOS

  16. Underlying “Theory” • Commodities are carried by trucks, rail, and other modes • Commodity flow patterns determine truck flow patterns • Truck characteristics vary substantially by commodity type and shipment distance • Mode share • Average value per ton • Size mix • Average payload weight • Unlike personal travel, commodity shipment choices are influenced very little by network LOS measures

  17. What does it do? • ACOM translates dollar flows of commodities from ISAM and AA into truck trips by four size categories • ISAM for E-E • AA for I-I • Both for E-I and I-E

  18. ACOM and Economic Models Relationships AA ISAM Internal to Internal Internal to External AA External to Internal External to External ISAM

  19. Production and Consumption Weights Distribute to Commodity Flow Matrices Convert to Truck Trips by STCC General Model Flow ISAM AA Distance

  20. Expand regions to ETAZs Expand using distance Production and Consumption Weights Region to region E-E flows by commodity Distribute to Commodity Flow Matrices Convert to Truck Trips by STCC External to External Flow ISAM AA Distance

  21. Allocate districts to TAZs Expand using distance Production and Consumption Weights Distribute to Commodity Flow Matrices Districts to districts flows and floor space by TAZ by commodity Convert to Truck Trips by STCC Internal to Internal Flow ISAM AA Distance

  22. Allocate districts to TAZs, regions to ETAZs ISAM Production and Consumption Weights AA Region shares of commodities Distribute using singly constrained gravity model Distribute to Commodity Flow Matrices Distance District exports and floor space by TAZ by commodity Convert to Truck Trips by STCC Internal to External Flow

  23. $ Flows to Truck Trips by Size Factors Total $’s to Truck $’s Distance Truck $’s to Truck tons Split Truck tons by Truck Size Convert to Truck trips by STCC Convert to time periods

  24. Calibration • Each of the models uses a gamma function to calculate deterrence as a function of distance and three parameters • The parameters can be adjusted up or down to match trip lengths and distribution shapes • Calibration Targets • Ohio county to external state for Statewide Cordon Roadside Survey • Selected MPO County to other Ohio counties truck trips from MPO Roadside Surveys • Average trip lengths by area from CFS97 and Transearch

  25. Average Truck Trip Lengths

  26. Average Truck Trip Lengths

  27. S3 Calibration OD Checks • Total auto and total truck trips crossing model area and Ohio cordons versus counts • Ohio county to external state auto and truck trips versus roadside survey for Ohio cordon • For counties entirely within MPO roadside survey cordon, OD flows to counties entirely outside MPO cordon versus MPO roadside survey

  28. MPO Roadside Survey Cordons

  29. OD Analysis Districts

  30. Initial results for auto vehicle trip OD (1)

  31. Initial results for auto vehicle trip OD (2)

  32. S3 Calibration Global Assignment Checks • VMT by FUNCLASS • Model Area • Ohio • MPO county groups • Major Screenline Volumes by FUNCLASS • Model Area cordon • Ohio cordon • MPO cordons • Source of independent VMT estimates? Counts versus “counts”

  33. Initial Unconstrained Auto Assignment ResultsSum of Link Flows for Links with Actual Year 2000 Counts (20,751 links)

  34. Initial Unconstrained Auto Assignment ResultsSum of Link Flows for Links with Actual Year 2000 Counts (20,751 links)

  35. Initial Unconstrained Auto Assignment ResultsAll Links

  36. Conclusions This framework allows us to be consistent. Calibration results look good so far. More work to be done.

  37. Questions for Pat?

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