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Overview Freight Modeling

Overview Freight Modeling. Tianjia Tang, PE., Ph.D FHWA, Office of Freight Management and Operations Tianjia.Tang@FHWA.DOT.GOV Phone: 202-366-2217. For more information on freight modeling…. www.fmip.gov www.ops.fhwa.dot.gov/freight. Presentation Outline. 1: Modeling Objective

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Overview Freight Modeling

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  1. Overview Freight Modeling Tianjia Tang, PE., Ph.D FHWA, Office of Freight Management and Operations Tianjia.Tang@FHWA.DOT.GOV Phone: 202-366-2217

  2. For more information on freight modeling… www.fmip.gov www.ops.fhwa.dot.gov/freight

  3. Presentation Outline 1: Modeling Objective 2: Modeling Approach 3: Method Classification 4: Challenges 5: Summary

  4. Modeling Objective Three main areas: 1: Economic development 2: Logistic and supply chain 3: Transportation planning and engineering

  5. Modeling Objective Three main areas: 1: Economic development 2: Logistic and supply chain 3: Transportation planning and engineering Private Business, Local, Regional, State, and Federal Government perform modeling for…

  6. Modeling Objective Three main areas: 1: Economic development 2: Logistic and supply chain 3: Transportation planning and engineering Private Business, Local, Regional, State, and Federal Government perform modeling for…

  7. Modeling Objective Based on the most recent TRB survey, freight modeling has been used to analyze… 1: Program level issues 2: Project level issues

  8. Modeling Objective Program level: 1) Long Range Plan and Transportation Improvement Plan 2) Conformity 3) Size and weight issues 4) Modal diversion issue 5) Others

  9. Modeling Objective Project level: 1) Bridge/roadway design 2) Corridor study 3) Modal diversion 4) Weight station/parking optimization 5) Hazmat 6) Others

  10. Modeling Objective Bottom Line … 1) … amount of freight goes into my jurisdiction

  11. Modeling Objective Bottom Line … 1) … amount of freight goes into my jurisdiction 2) … amount of freight goes out my jurisdiction

  12. Modeling Objective Bottom Line … 1) … amount of freight goes into my jurisdiction 2) … amount of freight goes out my jurisdiction 3) … amount of freight gets moved within my jurisdiction

  13. Modeling Objective Bottom Line … 1) … amount of freight goes into my jurisdiction 2) … amount of freight goes out my jurisdiction 3) … amount of freight gets moved within my jurisdiction 4) … amount of freight goes through my jurisdiction

  14. Modeling Objective Bottom Line … 1) … amount of freight goes into my jurisdiction 2) … amount of freight goes out my jurisdiction 3) … amount of freight gets moved within my jurisdiction 4) … amount of freight goes through my jurisdiction 5) … ways/methods these freights get moved

  15. Modeling Objective Time-line: Future Past Present

  16. Modeling Objective … Know the target !

  17. Modeling Approach …given the long history, knowledge, and experiences on passenger demand travel modeling… … simulating behavior … mechanistic based flow… empirical constructed…

  18. Modeling Approach …given the long history on passenger demand travel modeling… 1: Production 2: Distribution 3: Mode 4: Assignment …simulating behavior … mechanistic based flow and empirical constructed

  19. Method Classification 1: Commodity based 2: Trip generation rate based 3: Empirical statistical approach 4: Trend analysis Criteria: unique to freight models as compared with urban passenger models

  20. Commodity Based Method Commodity Production($/Tonnage) Commodity Distribution$/Tonnage Commodity Mode Split $/Tonnage Traffic Assignment Vehicle Trip Generation

  21. Commodity Based Modeling Method Commodity Production($/Tonnage) 1: To estimate the production and consumption of 2: Units of measure: tonnage and $ a given commodity

  22. Commodity Based Modeling Method Commodity Production($/Tonnage) …establish a base model/equation relating the production of a specific commodity to economic activities such as economic growth, employment, et al.

  23. Commodity Based Modeling Method Commodity Production($/Tonnage) Three Key Issues: 1: Commodity classification 2: Geographic level (size of the geographic area) 3: Economic activities: population, employment, payroll…

  24. Commodity Based Modeling Method Commodity Production($/Tonnage) Commodity Distribution$/Tonnage Commodity Mode Split $/Tonnage Traffic Assignment Vehicle Trip Generation

  25. Commodity Based Modeling Method Commodity Distribution$/Tonnage Commodity Production($/Tonnage) Commodity Consumption ($/Tonnage)

  26. Commodity Based Modeling Method Commodity Distribution$/Tonnage Commodity Production($/Tonnage) Commodity Specific Origin-Destination Data Commodity Consumption ($/Tonnage)

  27. Commodity Based Modeling Method Commodity Distribution$/Tonnage Methods in OD Data Development 1: Commodity Flow Survey: Gap Filling, disagregation, … 2: Gravity Model: single constrained, double constrained, spatial interaction…

  28. Commodity Based Modeling Method Commodity Distribution$/Tonnage CFS OD Methods … loglinear, ipf…

  29. Commodity Based Modeling Method Commodity Distribution$/Tonnage CPC Methods – gravity model …

  30. Commodity Based Modeling Method Commodity Production($/Tonnage) Commodity Distribution$/Tonnage Commodity Mode Split $/Tonnage Traffic Assignment Vehicle Trip Generation

  31. Commodity Based Modeling Method Commodity Mode Split $/Tonnage Rail Freight: STB’s annual waybill Water Freight: US ACOE annual S-S OD Truck Freight: most complicated Mode split data: Past, Current, and Future?

  32. Commodity Based Modeling Method Commodity Mode Split $/Tonnage Rail Freight: STB’s annual waybill For a given commodity, Modal share typically remains unchanged! Water Freight: US ACOE annual S-S OD Truck Freight: most complicated Mode split data: Past and Current ? Future?

  33. Commodity Based Modeling Method Commodity Production($/Tonnage) Commodity Distribution$/Tonnage Commodity Mode Split $/Tonnage Traffic Assignment Vehicle Trip Generation

  34. Commodity Based Modeling Method Vehicle Trip Generation Tonnage data are converted to # of truck loads

  35. Commodity Based Modeling Method Methods to Convert Tonnage to Truck Loads Data Sources used for conversion 1: Vehicle Inventory and Use Survey http://www.census.gov/svsd/www/02vehinv.html 2: Examples of State and local data http://www.scag.ca.gov/goodsmove/pdf/truckcnt_rpt.pdf http://www.sfta.wsu.edu/index.htm http://www.sfta.wsu.edu/presentation/pdf/6_steeringCommitteJune13.pdf

  36. Commodity Based Modeling Method Commodity Production($/Tonnage) Commodity Distribution$/Tonnage Commodity Mode Split $/Tonnage Traffic Assignment Vehicle Trip Generation

  37. Commodity Based Modeling Method Traffic Assignment 1: all or nothing 2: stochastic user equilibrium 3: user equilibrium 4: capacity restrained 5: system optimum 6:others Uniqueness of Freight Transport … the logistic industry urban routing

  38. Commodity Based Modeling Method Strength Based on fundamental economic activities… Weakness Exceedingly hard to validate and calibrate…

  39. Commodity Based Modeling Method More than a dozen states or MPOs developed their freight models based on the commodity approach For more specific state model information, visit links provided at: www.fmip.gov

  40. Trip Generation Rate Based Trip Production Trip Distribution Traffic Assignment

  41. Trip Generation Rate Based Trip Production # of truck trips generated per land use/employment/other activities…

  42. Trip Generation Rate Based Trip Distribution Gravity model Spatial intervention others

  43. Trip Generation Rate Based Traffic Assignment 1: all or nothing 2: stochastic user equilibrium 3: user equilibrium 4: capacity restrained 5: system optimum 6:others

  44. Trip Generation Rate Based Strength Availability of field count data … Weakness Multimodal issue and forecasting issue …

  45. Empirical Statistical Methods Completely different from the traditional 4 – steps modeling Number of vehicles N = f(land use, business locations, and other information)

  46. Empirical Statistical Methods Dependent Variable N= Observed Traffic count number Independent Variables Function classification of the roadway, adjacent land use type, major business distance ….

  47. Empirical Statistical Methods Strength Availability of truck count data … Weakness forecasting issue …

  48. Trend Analysis By examining the past traffic count data, and making linear extrapolation of the data to obtain future data… more on a project level…

  49. Challenges Big Picture 1: Modeling objective 2: Relationships between GDP and shipments 3: Economic sensitive modal data/model 4: Integration with other models

  50. Challenges Technical 1: Effective and efficient data collection methods 2: Freight distribution algorithm 3: Freight traffic assignment algorithm 4: Model calibration and validation

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