United States
Environmental Protection
Agency
Air and Energy Engineering
Research Laboratory
Research Triangle Park, NC 27711
Research and Development
EPA/600/SR-93/214 January 1994
&EPA Project Summary
Conceptual Designs for a
New Highway Vehicle
Emissions Estimation
Methodology
John T. Ripberger
This report discusses conceptual de-
signs from six contractors for a new
highway vehicle emissions estimation
methodology and summarizes the con-
tractors' recommendations for improv-
ing the emissions and activity factors
in the emissions estimation process.
The complete reports are included as
appendices. EPA asked these contrac-
tors to assist in developing ideas for a
future improved methodology to esti-
mate highway vehicle emissions. They
were selected because of their experi-
ence in working with mobile source
emissions inventories.
In general, the contractors suggest
developing new modules within the
emission estimation process to provide
users with more detailed information
on the causes of vehicle emissions.
The essence of these suggestions is
the need for more comprehensive inte-
gration of data between the transporta-
tion planning model and the emission
factor model. The reports reinforced
comments voiced by other experts for
modal data and more responsive trans-
portation models, although they did not
identify totally new concepts not al-
ready being considered by EPA re-
search programs.
This Project Summary was developed
by EPA's Air and Energy Engineering
Research Laboratory, Research Tri-
angle Park, NC, to announce key find-
ings of the research project that is fully
documented in a separate report of the
same title (see Project Report ordering
information at back).
Project Overview
In April 1991, six tasks were awarded
to look for new concepts that could poten-
tially provide improved emission inventory
estimates from highway vehicles in 5-10
years. Contractors were asked to submit
their ideas for a new highway vehicle emis-
sions estimation methodology. The request
to the contractors was to determine if,
because of changes in vehicle technolo-
gies, transportation analysis tools, and sci-
entific understandings, adoption of new
concepts could provide significant advan-
tages over existing methodologies. This
project was a follow-on to the two high-
way vehicle workshops held in the sum-
mer of 1990 to solicit recommendations
from emission inventory experts. The con-
tractors (Alliance Technologies Corp.,
Desert Research Institute, E. H. Pechan
& Associates, Inc., Radian Corp., Sierra
Research, Inc., and Systems Applications
International) were selected because of
their experience in using and developing
mobile source emission inventories for
EPA and California. E. H. Pechan & As-
sociates teamed with COMSIS Corpora-
tion to address transport modeling recom-
mendations. Ground rules for the study
were that: 1) emission inventory estimates
are used by EPA and states in models to
determine the effectiveness of various con-
trol strategies for achieving air quality stan-
dards; 2) the methods now available for
Printed on Recycled Paper
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estimating emissions from highway ve-
hicles will not be adequate for the new
fuels, technologies, and transportation con-
trol methods available in 5 to 10 years;
and 3) this project is intended to begin the
process of looking for an optimum meth-
odology for estimating emissions and en-
suring that the estimates meet future U.S.
needs. The results of this effort should
help produce better methods for estimat-
ing emissions from highway vehicles. The
time frame for implementing any new con-
cepts is 5 - 10 years.
This report summarizes the conceptual
designs received in 1991 from six con-
tractors. Their complete reports are in-
cluded as appendices. In general, the con-
tractors' reports suggest developing new
modules within the emission estimation
process to provide users with more de-
tailed information on the causes of vehicle
comprehensive integration of data between
the transportation planning model and the
emission factor model. To present the con-
tractors' recommendations clearly and to
avoid redundancy, this report combines
their concepts and organizes them ac-
cording to topic, rather than simply sum-
marizing each contractor's conceptual de-
sign separately. First, concepts on improv-
ing emission factors are considered, fol-
lowed by recommendations for improving
activity factors, and ideas for organizing
and coordinating the new emission and
transportation models.
As EPA develops its research program
to prepare emission inventory models for
the future, it is attempting to ensure that
no promising new concepts are over-
looked. This effort was to solicit ideas
from contractors experienced in estimat-
ing emissions from highway vehicles. For
the most part, the reports did not identify
any totally new concepts not already be-
ing considered by EPA research programs.
Most of the ideas were linked to existing
procedures, requiring much costly data
collection concerning vehicle emissions
and operations on highway networks. The
reports reinforced comments voiced by
other experts for modal data and more
responsive transportation models.
'U.S.Government Printing Office: 1994—550-067/80135
J. T. Ripberger is a Participant in the Earth Team Soil Conservation Service
Volunteer Program assisting the U.S. EPA.
Carl T. Ripberger is the EPA Project Officer (see below)
The complete report, entitled "Conceptual Designs for a New Highway Vehicle
Emissions Estimation Methodology," (Order No. PB94-120 128/AS; Cost:
$36.50, subject to change) will be available only from:
National Technical Information Service
5285 Port Royal Road
Springfield, VA 22161
Telephone: 703-487-4650
The EPA Author and Project Officer can be contacted at:
Air and Energy Engineering Research Laboratory
U.S. Environmental Protection Agency
Research Triangle Park, NC 27711
United States
Environmental Protection Agency
Center for Environmental Research Information
Cincinnati, OH 45268
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