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U.S. Department of Transportation
Comprehensive Truck Size and Weight Study
Report No. 3
Activity II: Task C
Refine Freight Diversion Models for All Modes
September 1995
Prepared by
Battelle
The primary objectives of the U.S. Department of Transportation's
Comprehensive Truck Size and Weight (TS&W) Study are to:
o assess the potential economic, safety, and
environmental impacts of changing existing TS&W limits;
and
o identify opportunities to increase the efficiency of
freight transportation while preserving safety and
highway infrastructure.
Reports which have been completed for the TS&W Study, to date,
include the following:
(1) Synthesis of Truck Size and Weight Studies and Issues
(2) Analysis of the Truck Inventory and Use Survey from the
Truck Size and Weight Perspective for Trucks with
Five-Axles or More
(3) Truck Size and Weight Modelling Workshop
(4) Truck Size and Weight Performance-Based Workshop
(5) Western U.S.-Canada Crossborder Case Study.
For more information, call Jim March, FHWA, 202-366-9233,
202-366-7696 (FAX), or e:mail: jim.march@fhwa.dot.gov
This document was prepared for use in the U.S. Department of
Transportation's Comprehensive Truck Size and Weight Study. The
views expressed are those of the author(s) and are not
necessarily those of the U.S. Department of Transportation.
Table of Contents
Executive Summary. . . . . . . . . . . . . . . . . . . . . ES-1
1.0 Introduction. . . . . . . . . . . . . . . . . . . . . . .1
2.0 Description of the Models Presented at the Workshop . . ..3
2.1 Highway Traffic Forecasting System (HTFS) Dave Greene
and Shih-Miao Chin, Oak Ridge National Laboratory(ORNL)
. . . .. . . . . . . . . . . . . . . . . . . . . . . 3
2.2 Freight Network Policy Model (FNET). . . . . . . . . 3
2.2.1 FNET System Implementation. . . . . . . . . . 3
2.2.2 Strengths of the FNET Policy Model. . . . . . 4
2.2.3 Concerns of the FNET Policy Model . . . . . . 4
2.2.4 Suggestions from the Discussion for the FNET
Policy Model . . . . . . . . . . . . . . . . .5
2.3 Truck Costs Truck Weight and Size Issues - Joe Stowers,
Sydec, Inc. and Herb Weinblatt, Cambridge Systematics,
Inc . . . . . . . . . . . . . . . . . . . . . . . . .5
2.3.1 Cost and Diversion Effects . . . . . . . . . 5
2.3.2 System Implementation. . . . . . . . . . . . 6
2.3.3 Results of the Research. . . . . . . . . . . 6
2.3.4 Strengths of the Approach Used by Sydec, Inc. 7
2.3.5 Concerns of the Model Used by Sydec, Inc. . . 7
2.3.6 Suggestions from the Discussion. . . . . . . 7
2.4 Logistics Data Issues and Freight Transportation
Analyzer (FTA) ModelGary Gittings and Gene Tyworth,
Penn State University (PSU), and David Middendorf,
(ORNL) . . . . . . . . . . . . . . . . . . . . . . . .8
2.4.1 The Shippers Survey and the Productivity
Effects of TS&W Policies Study, Freight
Transportation Analyzer (FTA) Model .. . . . .8
2.4.2 System Implementation. . . . . . . . . . . . .9
2.4.3 Results of the Productivity Effects of TS&W
Policies Research. . . . . . . . . . . . . .. 9
2.4.4 Strengths of the FTA Model . . . . . . . . . 9
2.4.5 Concerns of the FTA Computer Program . . . . 10
2.4.6 Suggestions from the Discussion for the FTA
Model. . . . . . . . . . . . . . . . . . . . 10
2.5 Truck-Rail/Rail-Truck Diversion Model
Raman Nanda and Bryan Smalley,Transmode Consultants 10
2.5.1 The Truck-Rail/Rail-Truck Diversion Model. . 10
2.5.2 System Implementation. . . . . . . . . . . . .11
2.5.3 Strengths of the Rail-Truck Diversion Model. .11
2.5.4 Concerns of the Rail-Truck Diversion Model. . 11
2.5.5 Suggestions from the Discussion for the
Rail-Truck Diversion Model. . . . . . . . . . 12
3.0 General Discussion of Issues at Workshop. . . . . . . . . 13
3.1 Commodity Flow Survey (CFS) and the Truck Inventory
Usage Survey (TIUS). . . . . . .. . . . . . . . . . 13
3.2 General Discussion Topics, Jim March, Federal Highway
Administration (FHWA). . . . . . . . . . . . . . . . 13
3.3 Further Research Topics. . . . . . . . . . . . . . . 14
4.0 Review of Models and Data Bases Available for Truck Size and
Weight Study. . . . . . . . . . . . . . . . . . . . . . . 15
4.1 Purpose. . . . . . . . . . . . . . . . . . . . . . . 15
4.2 Available Models and New Data Bases. . . . . . . . . 15
4.3 Status and Usefulness of Models and Data Bases . . . 16
4.4 Models Available . . . . . . . . . . . . . . . . . . 16
4.4.1 Truck-Rail/Rail-Truck Model. . . . . . . . .. 16
4.4.2 Freight Transportation Analyzer. . . . . . . 18
4.4.3 FNET . . . . . . . . . . . . . . . . . . . . .19
4.4.4 Intermodal Competition Model . . . . . . . . .20
4.4.5 NAPCOM . . . . . . . . . . . . . . . . . . . .20
4.4.6 BASIC. . . . . . . . . . . . . . . . . . . . 21
4.5 New Data Bases . . . . . . . . . . . . . . . . . . . 21
4.5.1 Truck Inventory and Use Survey (TIUS). . . . .21
4.5.2 Commodity Flow Survey. . . . . . . . . . . . .22
4.5.3 State Fuel and Registration Plans. . . . . . .22
4.5.4 NATS and NMTDB . . . . . . . . . . . . . . . .22
5.0 Recommendations . . . . . . . . . . . . . . . . . . . . . 24
Executive Summary
The Federal Highway Administration (FHWA) sponsored an informal
workshop on February 10, 1995, as part of a comprehensive truck
size and weight (TS&W) study. The objectives of the workshop
were to discuss past work in modeling issues and identify new
tools for TS&W analysis. Several experts gave presentations of
their models and prior TS&W work which demonstrated different
analytical approaches to the TS&W issue. Following the
presentations, there was group discussion of future research
needs to support TS&W analysis.
Overall, there was wide agreement among the workshop that there
is not one tool or combination of tools that is capable of
modeling the complexity of all the possible TS&W options that may
be considered. Furthermore, it was agreed that it probably will
not be possible to design one, all-inclusive tool. Consideration
should be given to conducting detailed case studies on specific
commodities, companies, and regions to supplement (or outright
replace) large complex models. Therefore, an integrated approach
involving several models and different data will most likely be
needed.
One major weakness that applied to all tools discussed was the
lack of accurate data bases for model inputs and case studies.
Some new data sources are likely to become available in the
near-term. The Bureau of the Census' 1992 Truck Inventory Usage
Survey (TIUS)and the Commodity Flow Survey (CFS) will hopefully
offer a better understanding of commodity flow shipments in the
country. In addition, the Bureau of Transportation Statistics
(BTS) is making available data on cross-border flow of goods.
One final overall observation from the workshop was that FHWA
should consider case studies of industry practices. This
approach differs from TS&W modeling, but could be used to build a
micro-approach for national TS&W analysis. For example,
different specialized models or case studies representing
individual commodities, geographic regions or corridors could be
developed. This specific information could be combined with
other case studies and built up to analyze the overall national
situation.
The first workshop presentation discussed the Freight Network
Policy Model (FNET) which is a component of the Highway Traffic
Forecasting System (HTFS). FNET mathematically estimates the
impacts of truck size and weight and highway user fee policy
options on changes in vehicle-miles travel (VMT) and payload ton
miles (PTM) by various operating weight classes and vehicle
types, truck and rail operational costs, and truck-rail modal
split.
A less mathematical but more "real world" approach are the Truck
Costs issues discussed in four studies of cost diversion effects
that were conducted over the last 15 years. These studies dealt
with the non-linehaul costs for extra trailers, diversion
potential, dedicated service, nondedicated service, cube-limited
versus weight-limited freight, local restrictions, shipper
requirements, effects on VMT, and transport costs.
Another approach is to study TS&W issues from the shipper's
perspective. The Pennsylvania State University (PSU) conducted a
survey of freight shippers. This survey information served as
inputs to the Freight Transportation Analyzer (FTA). The FTA is
a stochastic model which tries to find the nationwide diversion
and the net effects of LCVs on shippers total logistics costs.
The last presentation was the Truck-Rail/Rail-Truck (Rail-Truck)
Diversion Model. This model is a statistically disaggregate
model which uses a Shippers Logistics cost model. The Rail-Truck
Model is aimed at maximizing the receiver's utility while
minimizing the total logistic costs. This is done by calculating
the receivers utility for each transportation alternative. It
also approaches the problem from the perspective of the
shipper/receiver.
In addition to the models discussed at the Workshop, several data
bases (new and revised data bases) were also discussed. These
data bases potentially offer new and better sources of
information to address continuing weakness, particularly with
truck VMT and freight commodity flows.
There are several recommendations regarding specific tools and
data bases needed to support TS&W's analysis. These action items
need to be part of the TS&W Management Research Plan.
(1) The Rail-Truck Model should be reviewed extensively and
improved to be ready to measure nationwide rail to truck
diversion and rail revenue contribution impacts from changes
in Federal TS&W regulations. FHWA needs to have an
independent estimate of diversion potential and avoid being
in a situation of solely depending on the AAR's ICM model
for diversion estimates. This model needs to reflect the
latest trends and cost/pricing events from a variety of
studies, Battelle Team skills, and other models (FTA).
(2) The FHWA should investigate the likelihood of using North
American Trucking Survey(NATS) and the National Motor
Truckload Data Base (NMTDB) from the Association of American
Railroads (AAR). Also, the FHWA should address the value of
continuing a NATS/NMTDB-type data base collection project.
Perhaps,these data could be collected every two years or be
combined with other current truck data collection efforts
(i.e., TIUS). Related to this decision should be a review of
the Reebie data base and a collection method where the
trucking industry would provide data at no cost and get
national truck flow data for marketing purposes.
(3) The planned improvements to the NAPCOM need to be completed.
Also, future changes to the model should include tire
pressure, super single tire, and studded tire impacts on
pavement.
(4) Coordinate the review of the CFS and TIUS with other U.S.
Department of Transportation (DOT) offices and other
efforts. These data bases will be valuable to the TS&W
effort.
(5) The FNET needs to be reviewed for the data bases containing
the different highway networks and the GIS interface
capability. Also, we need to better the state regulation
data base and its usefulness in TS&W research. Currently,
the FNET is being used to estimate the benefits of
completing the Alameda Corridor in Los Angeles. This
exercise should be a good test case of the ease of use and
completeness of the model.
