Overview Freight Modeling Overview Tianjia Tang, PE., Ph.D FHWA, Office of Freight Management and Operations Phone:

For more information on freight modeling…

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

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

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

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

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

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

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

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

Time-line: 4 Present 4 Past 4 Future Modeling Objective

… Know the target ! Modeling Objective

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

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

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

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

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 Production ($/Tonnage) …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 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 Production ($/Tonnage) Commodity Distribution $/Tonnage Commodity Mode Split $/Tonnage Vehicle Trip Generation Traffic Assignment

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

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 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 Distribution $/Tonnage CFS OD Methods … loglinear, ipf…

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

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

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

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 Production ($/Tonnage) Commodity Distribution $/Tonnage Commodity Mode Split $/Tonnage Vehicle Trip Generation Traffic Assignment

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 Survey 2: Examples of State and local data Commodity Based Modeling Method Methods to Convert Tonnage to Truck Loads Methods to Convert Tonnage to Truck Loads

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

Commodity Based Modeling Method 1: all or nothing2: stochastic user equilibrium 3: user equilibrium 4: capacity restrained 5: system optimum 6:others Traffic Assignment Uniqueness of Freight Transport … the logistic industry urban routing

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 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:

Trip Generation Rate Based Trip Production Trip Distribution Traffic Assignment

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

Trip Generation Rate Based Gravity model Spatial intervention others Trip Distribution

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

Trip Generation Rate 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 Completely different from the traditional 4 – steps modeling Number of vehicles N = f(land use, business locations, and other information)

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

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

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…

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

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

SummarySummary 1: Objective 2: Approach 3: Types of Freight Models 4: Challenges

That’s All. Thank You!