F R E I G H T T R A N S P O R T M O D E L I N G

( C I V L 7 9 0 9 - 8 9 0 9 )

D E P A R T M E N T O F C I V I L E N G I N E E R I N G

U N I V E R S I T Y

U N I V E R S I T Y O F M E M P H I S

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Lecture-2: Freight Trip Generation

and Land Use

09/05/2014

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Materials used in today’s lecture are from

NCHRP 739/ NCFRP 19

Topics3

Main Points

Land Use Classifications

Freight and Land Use

FG/FTG Models

Future Steps

Main Points-1

*North-American Industry Classification System (NAICS), Land-Based Classification Standards (LBCS)

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Freight Generation (FG) is different than Freight Trip (Truck) Generation

Homogeneous classes of land use in terms of determinants and patterns of FG/FTG (heavily dependent on land use classification system e.g. NAICS vs. LBCS*)

Predictors of FG/FTG should correctly measure intensity of activity (e.g. three establishments of the same size will generate different freight based on usage- low, medium, high)

Main Points-25

Use the aggregation procedure that corresponds to the underlying disaggregate FG/FTG model (e.g. do not multiply average rates with total area of a zone)

Economic classification (NAICS) is superior to standard land use classifications (LBCS)

Need for a “translation” from one to the other (i.e. from LBCS to NAICS – something similar from SIC to NAICS)

Main Points-36

Same economic models maybe more appropriate for productions and others for attractions (e.g. NAICS for vehicle trip production, SIC vehicle trip attraction)

Transferability of models? Yes but not a solid answer

Land Use Classifications7

ITE Trip Generation Manual

Local real property assessors’ tax classifications

Local land use planning classification systems

The Standard Land Use Coding Manual (SLUCM)

Land-Based Classification Standards (LBCS) developed by the Federal Highway Administration (FHWA), American Planning Association (APA), and other federal agencies

Employment categories: SIC codes; NAICS

Remote Sensing

Case by case

New York’s Tax Assessor’s classification codes for freight-related land uses

Source: NCHRP 739-NCFRP 19

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SLUCM categories for freight

Standard Land Use Coding Manual (SLUCM)

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Source: NCHRP 739-NCFRP 19

Land-Based Classification Standards (LBCS)10

LBCS Classifies Land uses by

Activity (farming, shopping manufacturing)

Function (agricultural, commercial, industrial)

Structural character (single family housing, warehouse)

Site development character (developed or not)

Ownership (private, public)

Land-Based Classification Standards (LBCS)11

Source: NCHRP 739-NCFRP 19

SIC and NAICS

Standard Industrial Classification (SIC) Codes, North-American Industry Classification System (NAICS),

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Source: NCHRP 739-NCFRP 19

Remote Sensing13

Source: NCHRP 739-NCFRP 19

Case by Case14

Source: NCHRP 739-NCFRP 19

Tier 1: Goods

movement very

important

Tier 2: Depend on

goods movement in a

secondary manner

So What?

Cross-walks a.k.a. tranlsation

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No single land use system appropriate for freight

New definitions are appearing by individual agencies to serve their needs

“Cross-walks” and GIS make it easier to integrate Land Use Classifications

No system is perfect

Freight System and Land Use16

Freight System17

To understand freight you need to understand underlying supply chain

FT and FTG must consider Production at shippers

Intermediate points (e.g. D.Cs)

Consumer sites

Consumers are usually overlooked (especially in urban areas) 6,600 restaurants in Manhattan produce more FTG than Port of NY

and NJ terminals combined!!!!!!

Supply Chain View of Players

Source: NCHRP 739-NCFRP 19

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Supply Chain Functions and Geography(relating to FTG)

Source: NCHRP 739-NCFRP 19

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TG: Passenger vs. Freight20

Proportionality works for passenger not freight 1.2 cars per person

2.3 truck trips per square footage????

Two industries of the same type with the same square footage can produce different truck trips (economies of scale, type of deliveries, usage of facility, ownership of facility, seasonality)

Production Passenger: Based on socioeconomic characteristics (household level)

Freight: Based on inventory policies and logistic costs (company/establishment characteristics)

Biggest challenge: Include logistic decisions into freight demand modeling (generation, mode choice, distribution, assignment)

Key Note-121

FTG does not (necessarily) depend on business size

Small vendors may produce higher number (and more frequent) truck trips

Also a lot of empties

Why? Economies of scale and business operation

Key Note-222

FTG and Mode Choice Combined

Logistic Decisions and Inventory

Interactions Between Players and Decisions on Shipment Size and

Frequency

Logistics Influence Example

Source: NCHRP 739-NCFRP 19

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Q*: Quantity Ordered, T*: Time Between Orders, f* : Order Frequency

Attributes Influencing FTG24

Land Use

Economic Activity

Employment

Business Area

Industry Segment

Commodity Type

Gross Floor Area

Methods for FG Estimation25

Regression

Time Series

Input/Output Models (FG) Needs cross-walk from FG to FTG (e.g. truck load factors)

Pattern Recognition/Data Mining

Equilibrium Models (mainly in Europe)

Factors Affecting FTG-1

Source: NCHRP 739-NCFRP 19

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Factors Affecting FTG-2

Source: NCHRP 739-NCFRP 19

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Key Note-328

FG increases with business size NOT FTG

Small businesses tend to produce proportionally more FTG than large ones (smaller trucks though and VMT)

FG increases with size, FTG often does so at a slower rate

Both FG and FTG rates depend on business size

FTG Possible Predictors: industry segment, employment, sales, commodity, type, and square footage

FTG and Land Use Connections

Source: NCHRP 739-NCFRP 19

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Freight Generation Approaches Pros and Cons

Source: NCHRP 739-NCFRP 19

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Issues31

Lack of uniformity in the definition of land use classes

Land use classes (typically) group together heterogeneous (different FTG patterns) sectors

All FTG rates not transferable

Use of incorrect predictors (e.g. square footage)

Different land use grouping for FG and FTG

Redesign Suggestions32

Develop FG and FTG that properly linked to the land use classification system being used at a

particular jurisdiction

land use classification systems consistent with patterns of FG and FTG

use CFS micro-data for various industries

tool development to allow agencies to mix different industry FTGs models in their region (i.e. Zip code business pattern data and a cross walk to freight trips)

Model FG and FTG SEPARATELY

Suggested Steps33

1. Take advantage of a massive data set that is collected every 5 years and covers almost all relevant economic sectors in the nation

2. Produce FG/FTG models using 1 and 2

3. Map industry sector models to land use definitions of agency (e.g. MPO, DOT)

4. Use 2 and 3 to produce FG and FTG for area under consideration

FG/FTG Models

Source: NCHRP 739-

NCFRP 19

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Factors to be considered in developing and analyzing freight modeling techniques

Literature Model Summary-1 35

Dependent variable (predicted) 47% use vehicle trips, 38% use commodity tonnage; and 15% use a

combination (vehicle internal-internal trips and commodity tonnage for the rest of the flows)

38% of the models are aggregated, 48% are disaggregated, and others (14%) cannot be determined from the review

Independent Variable (predictor): employment by industry sector (49%);

building area (9%);

commodity type (13%);

land use (2%);

other variables (27%)

Literature Model Summary-2 36

Modeling technique

least square 25%,

trip rates 10%,

Multiple classification analysis 6%

IO 33%

Aggregation level

35% state

39% metropolitan areas

Modeling: Planning vs. Engineering37

Planning applications:

FG/FTG for conglomerations of users—typically defined by a zoning system

Medium-long term for state, regional, corridor or urban level

Engineering applications:

Provide input to design issues, traffic operation studies, impact analysis, parking

Single establishment or single location with multiple establishment (e.g. mall)

Modeling: Planning38

Predicted variable

46% vehicle trips; 49% commodity tonnage; 5% combination

Predictors

employment by industry sector (62%); population (36%); land use variables (5%); other variables (23%)

Modeling techniques

33% regression, 23% IO, 13% FTG, cross classification (5%), matrix estimation (8%), time series analysis (1%)

FTG Modeling: Engineering39

ITE Trip Generation Manual

Land use based average trip rate and regression equation

Independent variable: employees, gross floor area, number of vehicles

Quick Response Freight Manual

General guidelines for data collection and methodology

Site specific trip generation rates and regression equations

Trip rates are provided for SIC by employees, office space and acreage

Future Steps40

Enhance FTG NCFRP 25 Models Database

Research on Service Trips

Standardize Instruments/Design for Data Collection

Use CFS Micro-Data for FG (also need to convert FG to FTG)

Land Use Categories that Capture FG and FTG

Use of Advanced Modeling Techniques (e.g. Bayesian Regression, Multiple Class Analysis, Synthetic Correction etc)

Take Away Points-141

FG is different to FTG

FG: Economic input and output

FTG: Logistic decisions

Accuracy depends on

Classification of establishments in correct classes

Ability of the business size measure used to capture intensity of production/attraction

Validity of modeling technique

Correctness of aggregation procedure

Take Away Points-242

Three land use categories Structure type or site descriptor (e.g. ITE Manual)

Industry sector based (NAICS, SIC)

Land use planning designations (e.g. LBCS)

No single land use classification system is appropriate

Economic based classification superior to standard land use (in other words group based on parameters that describe production/attraction better)

F R E I G H T T R A N S P O R T M O D E L I N G

( C I V L 7 9 0 9 - 8 9 0 9 )

D E P A R T M E N T O F C I V I L E N G I N E E R I N G

U N I V E R S I T Y

U N I V E R S I T Y O F M E M P H I S

43

Lecture-2: Freight Trip Generation

and Land Use

09/05/2014

44