overview freight modeling overview tianjia tang, pe., ph.d fhwa, office of freight management and...
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OverviewOverviewFreight ModelingFreight Modeling
OverviewOverviewFreight ModelingFreight Modeling
Tianjia Tang, PE., Ph.D
FHWA, Office of Freight Management and OperationsTianjia.Tang@FHWA.DOT.GOV
Phone: 202-366-2217
www.fmip.gov www.fmip.gov
www.ops.fhwa.dot.gov/freightwww.ops.fhwa.dot.gov/freight
For more information on freight modeling…
1: Modeling Objective2: Modeling Approach3: Method Classification4: Challenges5: Summary
Presentation OutlinePresentation OutlinePresentation OutlinePresentation Outline
Three main areas:1: Economic development2: Logistic and supply chain3: Transportation planning
and engineering
Modeling ObjectiveModeling ObjectiveModeling ObjectiveModeling Objective
Modeling ObjectiveModeling ObjectiveModeling ObjectiveModeling Objective
Private Business, Local, Regional, State, and Federal Government perform modeling for…
Private Business, Local, Regional, State, and Federal Government perform modeling for…
Three main areas:1: Economic development2: Logistic and supply chain3: Transportation planning
and engineering
Modeling ObjectiveModeling ObjectiveModeling ObjectiveModeling Objective
Private Business, Local, Regional, State, and Federal Government perform modeling for…
Private Business, Local, Regional, State, and Federal Government perform modeling for…
Three main areas:1: Economic development2: Logistic and supply chain3: Transportation planning
and engineering
Based on the most recent TRB survey, freight modeling has been used to analyze…
1: Program level issues2: Project level issues
Modeling ObjectiveModeling ObjectiveModeling ObjectiveModeling Objective
Program level:
1) Long Range Plan and Transportation Improvement Plan
2) Conformity3) Size and weight issues4) Modal diversion issue5) Others
Modeling ObjectiveModeling ObjectiveModeling ObjectiveModeling Objective
Project level:
1) Bridge/roadway design 2) Corridor study3) Modal diversion4) Weight station/parking
optimization5) Hazmat6) Others
Modeling ObjectiveModeling ObjectiveModeling ObjectiveModeling Objective
1) … amount of freight goes into my jurisdiction
Modeling ObjectiveModeling ObjectiveModeling ObjectiveModeling Objective
Bottom Line …
1) … amount of freight goes into my jurisdiction2) … amount of freight goes out my jurisdiction
Modeling ObjectiveModeling ObjectiveModeling ObjectiveModeling Objective
Bottom Line …
1) … amount of freight goes into my jurisdiction2) … amount of freight goes out my jurisdiction3) … amount of freight gets moved within my
jurisdiction
Modeling ObjectiveModeling ObjectiveModeling ObjectiveModeling Objective
Bottom Line …
1) … amount of freight goes into my jurisdiction2) … amount of freight goes out my jurisdiction3) … amount of freight gets moved within my
jurisdiction4) … amount of freight goes through my
jurisdiction
Modeling ObjectiveModeling ObjectiveModeling ObjectiveModeling Objective
Bottom Line …
1) … amount of freight goes into my jurisdiction2) … amount of freight goes out my jurisdiction3) … amount of freight gets moved within my
jurisdiction4) … amount of freight goes through my
jurisdiction5) … ways/methods these freights get moved
Modeling ObjectiveModeling ObjectiveModeling ObjectiveModeling Objective
Bottom Line …
Time-line:Time-line:
PresenPresentt
PastPast
FutureFuture
Modeling ObjectiveModeling ObjectiveModeling ObjectiveModeling Objective
04/20/23 … … Know the Know the
target !target !… … Know the Know the
target !target !
Modeling ObjectiveModeling ObjectiveModeling ObjectiveModeling Objective
Modeling ApproachModeling ApproachModeling ApproachModeling Approach
… simulating behavior … mechanistic based flow… empirical constructed…
… simulating behavior … mechanistic based flow… empirical constructed…
…given the long history, knowledge, and experiences on passenger demand travel modeling…
Modeling ApproachModeling ApproachModeling ApproachModeling Approach
…simulating behavior … mechanistic based flow and empirical constructed
…given the long history on passenger demand travel modeling…
1: Production2: Distribution3: Mode4: Assignment
1: Production2: Distribution3: Mode4: Assignment
1: Commodity based2: Trip generation rate based3: Empirical statistical approach4: Trend analysis
Method ClassificationMethod ClassificationMethod ClassificationMethod Classification
Criteria: unique to freight models as compared with urban passenger models
Commodity Based Method Commodity Based Method Commodity Based Method Commodity Based Method
Commodity Production
($/Tonnage)
Commodity Distribution
$/Tonnage
Commodity Mode Split $/Tonnage
Vehicle Trip Generation
Traffic Traffic AssignmentAssignment
Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method
Commodity Production
($/Tonnage)
1: To estimate the production and consumption of
2: Units of measure: tonnage and $ a given commodity
Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method
Commodity Production
($/Tonnage)
…establish a base model/equation relating the production of a specific commodity to economic activities such as economic growth, employment, et al.
…establish a base model/equation relating the production of a specific commodity to economic activities such as economic growth, employment, et al.
Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method
Commodity Production
($/Tonnage)
Three Key Issues:
1: Commodity classification
2: Geographic level (size of the geographic area)
3: Economic activities: population, employment, payroll…
Three Key Issues:
1: Commodity classification
2: Geographic level (size of the geographic area)
3: Economic activities: population, employment, payroll…
Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method
Commodity Production
($/Tonnage)
Commodity Distribution
$/Tonnage
Commodity Mode Split $/Tonnage
Vehicle Trip Generation
Traffic Traffic AssignmentAssignment
Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method
Commodity Distribution
$/Tonnage
Commodity Production
($/Tonnage)
Commodity Production
($/Tonnage)
Commodity Consumption
($/Tonnage)
Commodity Consumption
($/Tonnage)
Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method
Commodity Distribution
$/Tonnage
Commodity Production
($/Tonnage)
Commodity Consumption
($/Tonnage)
Commodity Specific
Origin-Destination Data
Commodity Specific
Origin-Destination Data
Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method 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…
1: Commodity Flow Survey: Gap Filling, disagregation, …
2: Gravity Model: single constrained, double constrained, spatial interaction…
Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method
Commodity Distribution
$/Tonnage
CFS OD Methods … loglinear, ipf…
area # 1 2 3 4 5 6 71 25 36 21 7 12 0 82 4 41 28 73 2 12 22 2 5 84 5 24 12 215 6 33 61 0 56 12 45 64 35 24 0
Production
Consumption
Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method
Commodity Distribution
$/Tonnage
CPC Methods – gravity model …area # Production Consumption
1 25 362 4 413 2 124 5 5 6 336 12 457 08 219 25 2210 1 211 9 812 6 613 12 14
Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method
Commodity Production
($/Tonnage)
Commodity Distribution
$/Tonnage
Commodity Mode Split $/Tonnage
Vehicle Trip Generation
Traffic Traffic AssignmentAssignment
Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method
Rail Freight: STB’s annual waybill Rail Freight: STB’s annual waybill
Commodity Mode Split $/Tonnage
Water Freight: US ACOE annual S-S OD Water Freight: US ACOE annual S-S OD
Truck Freight: most complicated Truck Freight: most complicated
Mode split data: Past, Current, and Future? Mode split data: Past, Current, and Future?
Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method
Rail Freight: STB’s annual waybill
Water Freight: US ACOE annual S-S OD
Truck Freight: most complicated
Mode split data: Past and Current ? Future?
For a given commodity,
Modal share typically
remains
unchanged!
Commodity Mode Split $/Tonnage
Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method
Commodity Production
($/Tonnage)
Commodity Distribution
$/Tonnage
Commodity Mode Split $/Tonnage
Vehicle Trip Generation
Traffic Traffic AssignmentAssignment
Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method
Tonnage data are converted to # of truck loads
Tonnage data are converted to # of truck loads
Vehicle Trip Generation
Data Sources used for conversion
1: Vehicle Inventory and Use Surveyhttp://www.census.gov/svsd/www/02vehinv.html
2: Examples of State and local data http://www.scag.ca.gov/goodsmove/pdf/truckcnt_rpt.pdf http://www.sfta.wsu.edu/index.htm http://www.sfta.wsu.edu/presentation/pdf/6_steeringCommitteJune13.pdf
Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method
Methods to Convert Tonnage to Truck Loads
Methods to Convert Tonnage to Truck Loads
Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method
Commodity Production
($/Tonnage)
Commodity Distribution
$/Tonnage
Commodity Mode Split $/Tonnage
Vehicle Trip Generation
Traffic Traffic AssignmentAssignment
Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method
1: all or nothing 2: stochastic user equilibrium 3: user equilibrium 4: capacity restrained 5:
system optimum 6:others
1: all or nothing 2: stochastic user equilibrium 3: user equilibrium 4: capacity restrained 5:
system optimum 6:others
Traffic Traffic AssignmentAssignment
Uniqueness of Freight Transport …the logistic industry
urban routing
Uniqueness of Freight Transport …the logistic industry
urban routing
Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method
Strength
Based on fundamental economic activities…
Strength
Based on fundamental economic activities…
Weakness
Exceedingly hard to validate and calibrate…
Weakness
Exceedingly hard to validate and calibrate…
Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method Commodity Based Modeling Method
More than a dozen states or MPOs developed their freight models based
on the commodity approach
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
For more specific state model information, visit links provided at:
www.fmip.gov
Trip Generation Rate Trip Generation Rate Based Based Trip Generation Rate Trip Generation Rate Based Based
Trip Production
Trip Distribution
Traffic Traffic AssignmentAssignment
Trip Generation Rate Trip Generation Rate Based Based Trip Generation Rate Trip Generation Rate Based Based
Trip Production
# of truck trips generated per land use/employment/other
activities…
# of truck trips generated per land use/employment/other
activities…
Trip Generation Rate Trip Generation Rate Based Based Trip Generation Rate Trip Generation Rate Based Based
Gravity model Spatial intervention
others
Gravity model Spatial intervention
others
Trip Distribution
Trip Generation Rate Trip Generation Rate Based Based Trip Generation Rate Trip Generation Rate Based Based
Traffic Traffic AssignmentAssignment
1: all or nothing 2: stochastic user
equilibrium 3: user equilibrium
4: capacity restrained 5: system optimum
6:others
1: all or nothing 2: stochastic user
equilibrium 3: user equilibrium
4: capacity restrained 5: system optimum
6:others
Trip Generation Rate Trip Generation Rate Based Based Trip Generation Rate Trip Generation Rate Based Based
Strength
Availability of field count data …
Strength
Availability of field count data …
Weakness
Multimodal issue and forecasting issue …
Weakness
Multimodal issue and forecasting issue …
Empirical Statistical Methods Empirical Statistical Methods Empirical Statistical Methods Empirical Statistical Methods
Completely different from the traditional 4 – steps modelingCompletely different from the traditional 4 – steps modeling
Number of vehicles N = f(land use, business locations, and other information)
Empirical Statistical Methods Empirical Statistical Methods Empirical Statistical Methods Empirical Statistical Methods
Dependent Variable N= Observed Dependent Variable N= Observed Traffic count number Traffic count number
Independent VariablesIndependent Variables
Function classification of the roadway, Function classification of the roadway, adjacent land use type, major business adjacent land use type, major business
distance ….distance ….
Strength
Availability of truck count data …
Strength
Availability of truck count data …
Weakness
forecasting issue …
Weakness
forecasting issue …
Empirical Statistical Methods Empirical Statistical Methods Empirical Statistical Methods Empirical Statistical Methods
Trend Analysis Trend Analysis Trend Analysis 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…
By examining the past traffic count data, and making linear extrapolation of the data to obtain future data… more on a
project level…AADT Vs. Calendar Year
45000
47500
50000
52500
55000
57500
60000
1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011
Calendar year
AA
DT
ChallengesChallengesChallengesChallenges
1: Modeling objective
2: Relationships between GDP and shipments
3: Economic sensitive modal data/model
4: Integration with other models
Big Picture
ChallengesChallengesChallengesChallenges
1: Effective and efficient data collection methods
2: Freight distribution algorithm
3: Freight traffic assignment algorithm
4: Model calibration and validation
Technical
SummarySummarySummarySummary
1: Objective
2: Approach
3: Types of Freight Models
4: Challenges
That’s All. Thank You!That’s All. Thank You!That’s All. Thank You!That’s All. Thank You!
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