lecture-2: freight trip generation and land use - memphis · freight: based on inventory policies...
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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
1
Lecture-2: Freight Trip Generation
and Land Use
09/05/2014
2
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)
4
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
8
SLUCM categories for freight
Standard Land Use Coding Manual (SLUCM)
9
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),
12
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
15
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
18
Supply Chain Functions and Geography(relating to FTG)
Source: NCHRP 739-NCFRP 19
19
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
23
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
26
Factors Affecting FTG-2
Source: NCHRP 739-NCFRP 19
27
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
29
Freight Generation Approaches Pros and Cons
Source: NCHRP 739-NCFRP 19
30
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
34
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
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