Full text of DOI:10.1080/10473289.2002.10470838

This article was downloaded by: [Universidad Autonoma de Barcelona]
On: 20 October 2014, At: 03:29
Publisher: Taylor & Francis
Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House,
37-41 Mortimer Street, London W1T 3JH, UK
Journal of the Air & Waste Management Association
Publication details, including instructions for authors and subscription information:
http://www.tandfonline.com/loi/uawm20
Effects of Engine Speed and Accessory Load on Idling
Emissions from Heavy-Duty Diesel Truck Engines
Christie-Joy Brodrick a , Harry A. Dwyer a , Mohammad Farshchi b , D. Bruce Harris c & Foy G.
King Jr. c
a Institute of Transportation Studies, University of California–Davis , California , USA
b Sharif University of Technology , Tehran , Iran
c National Risk Management Research Laboratory, Office of Research and Development , U.S.
Environmental Protection Agency , Research Triangle Park , North Carolina , USA
Published online: 27 Dec 2011.
To cite this article: Christie-Joy Brodrick , Harry A. Dwyer , Mohammad Farshchi , D. Bruce Harris & Foy G. King Jr. (2002)
Effects of Engine Speed and Accessory Load on Idling Emissions from Heavy-Duty Diesel Truck Engines, Journal of the Air &
Waste Management Association, 52:9, 1026-1031, DOI: 10.1080/10473289.2002.10470838
To link to this article: http://dx.doi.org/10.1080/10473289.2002.10470838
PLEASE SCROLL DOWN FOR ARTICLE
Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained
in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no
representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the
Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and
are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and
should be independently verified with primary sources of information. Taylor and Francis shall not be liable for
any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever
or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of
the Content.
This article may be used for research, teaching, and private study purposes. Any substantial or systematic
reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any
form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http://
www.tandfonline.com/page/terms-and-conditions

Brodrick et al.
TECHNICAL PAPER
ISSN 1047-3289 J. Air & Waste Manage. Assoc. 52:1026-1031
Copyright 2002 Air & Waste Management Association
Effects of Engine Speed and Accessory Load on
Idling Emissions from Heavy-Duty Diesel Truck Engines
Christie-Joy Brodrick and Harry A. Dwyer
Institute of Transportation Studies, University of California–Davis, California
Mohammad Farshchi
Sharif University of Technology, Tehran, Iran
D. Bruce Harris and Foy G. King, Jr.
National Risk Management Research Laboratory, Office of Research and Development,
U.S. Environmental Protection Agency, Research Triangle Park, North Carolina
ABSTRACT
increase in NOx emissions in grams per hour, a 2-fold in-
crease in CO2 emissions, and a 5-fold increase in CO emis-
sions while idling. On a grams per gallon fuel basis, NOx
emissions while idling were approximately twice as high
as those at 55 mph. The CO2 emissions at the two condi-
tions were closer. The NOx emissions from the 1999 truck
while idling with air conditioning running were slightly
more than those of two 1990 model year trucks under
equivalent conditions, and the hydrocarbon (HC) and CO
emissions were significantly lower. It was found that the
NOx emissions used in the California Air Resources Board’s
(CARB) EMFAC2000 and the U.S. Environmental Protec-
tion Agency’s (EPA) MOBILE5b emissions inventory mod-
els were lower than those measured in all of the idling
conditions tested on the 1999 truck.
A nontrivial portion of heavy-duty vehicle emissions of
NOx and particulate matter (PM) occurs during idling.
Regulators and the environmental community are inter-
ested in curtailing truck idling emissions, but current
emissions models do not characterize them accurately, and
little quantitative data exist to evaluate the relative effec-
tiveness of various policies. The objectives of this study
were to quantify the effect of accessory loading and en-
gine speed on idling emissions from a properly function-
ing, modern, heavy-duty diesel truck and to compare these
results with data from earlier model year vehicles. It was
found that emissions during idling varied greatly as a func-
tion of engine model year, engine speed, and accessory
load conditions. For the 1999 model year Class 8 truck
tested, raising the engine speed from 600 to 1050 rpm
and turning on the air conditioning resulted in a 2.5-fold
INTRODUCTION
Heavy-duty diesel trucks produce relatively high amounts
of NOx and particulate matter (PM) compared with light-
duty vehicles. For the ~458,000 line-haul trucks in the United
States, which may idle overnight,1 limited evidence suggests
the amount of these emissions that occur during idling may
be significant.2 Idling is also fuel-inefficient. It was found
that during idling, the engine is only 3–11% efficient com-
pared with the greater than 30% efficiency achieved in high-
way operation. Idling fuel consumption is estimated to be
between 838 million and 2 billion gallons annually.1,3 In
addition to excess air pollutants and fuel consumption,
heavy-duty truck idling causes engine wear, noise, and vi-
brations. The impacts of tractor vibration and noise are dif-
ficult to quantify but are special concerns because of their
potential impact on driver sleeping and fatigue.
IMPLICATIONS
Research has shown that fuel consumption during truck
idling varies as a function of engine model year, acces-
sory loading, and engine speed. It is logical that emis-
sions change along with fuel economy. This paper pre-
sents data on the effect of engine model year, accessory
loading, and engine speed on emissions during heavy-
duty diesel truck idling. NOx, CO, CO2, and HC emissions
were measured by EPA on four different vehicles, with
the most extensive testing being conducted on a vehicle
with a 1999 model year engine. The results are compared
with idling emissions factors obtained from CARB’s
EMFAC2000 and EPA’s MOBILE5b emissions inventory
models. The methodology of measuring idling emissions
as a function of multiple factors can be employed to ob-
tain improved emissions factors for the idling portions of
the emissions inventory models.
Truck drivers idle their engines to power sleeper-com-
partment heaters and air conditioners, to power “hotel”
1026 Journal of the Air & Waste Management Association
Volume 52 September 2002

Brodrick et al.
accessories (televisions, refrigerators, computers, tools, and
fleet operations systems) during nondriving operations,
to avoid start-up problems in cold weather, to maintain
air system pressure, and simply as general practice during
many delivery operations. Auxiliary power units and other
options to reduce idling have received little market ac-
ceptance, with a market penetration of ~5% according to
industry estimates.4 As a result, heavy-duty line-haul trucks
in the United States continue to idle.
accessory loading, and engine speed. It follows that emis-
sions also would be affected by these factors. Engine
model year is a large factor because emissions standards
and engine design differ. Limited evidence, provided by
the present study, suggests that idling emissions from some
electronically controlled engines may be affected by idle
duration and vehicle operation prior to idling. Regardless
of engine design, older engines are more likely to have
increased emissions because of deterioration, poor main-
tenance, and tampering.
Little data exist about the amount of truck idling. One
study used a 6 hr/day idling time as a baseline case and a
range of 3.3 to 16.5 hr/day depending on the season and
operations.1 Some fleets reported vehicles idling up to 10
hr/day, or greater than 50% of the total engine run time.
This is consistent with fleet interview data collected by
Stodolsky et al.1
In most states, trucks and buses that are idling can be
ticketed under state nuisance laws, but this has been in-
frequent.5 In response to health concerns about diesel
particulates, there has been a recent surge of interest in
curtailing idling emissions. Regulators are pursuing a va-
riety of strategies to curtail idling. For 2001, the Califor-
nia Air Resource Board’s (CARB) Low Emissions Incentive
Program (Carl Moyer) added a monetary incentive for the
purchase of an auxiliary power unit that would be used
in lieu of idling.6 In December 2000, the Texas Natural
Resources Conservation Council approved a ban on truck
idling in the eight-county Houston area as part of their
clean-air attainment plan.7 To determine the effectiveness
of idling-reduction policies, such as incentives and bans,
it will be necessary to estimate the emissions reductions
associated with the decreased idling.
Accessory loading and engine speed affect the torque-
speed region in which the engine operates, and this in
turn affects the emissions and fuel consumption. The ac-
tual accessories and their power requirements determine
accessory loading. These loads vary from large power de-
mand by air-conditioning compressors to small power
demands from hotel accessories such as televisions. Truck-
ers often increase the idle speed from its default setting to
prevent battery drain and to improve accessory perfor-
mance. The extent to which truckers increase engine idling
speed is not documented, but truck manufacturers and
fleet owners indicate it is a common practice. In fact, some
trucks are equipped with physical and electronic throttle
controls that allow engine speed to be set during idle.
To the best of our knowledge, no data have been pub-
lished on truck idling emissions as a function of engine
model year, accessory loading, and engine speed. The U.S.
Department of Energy (DOE) publishes a table that esti-
mates fuel consumption as a function of brake horsepower
(bhp) demand of accessories and engine speed for the
general truck population. The numbers suggested by the
DOE are shown in Table 1.10 The fuel consumption ranges
from 0.6 gal/hr for a truck idling at 800 rpm with no ac-
cessories to 2.25 gal/hr for a truck idling at 1200 rpm with
30 bhp of accessories. The objectives of this study were to
quantify the effect of accessory loading and engine speed
on idling emissions from a properly functioning, mod-
ern, heavy-duty diesel truck and to compare these results
with data from earlier model year vehicles.
Very little quantitative data exist on the emissions
and fuel consumption characteristics of truck idling.1,8 In
fact, in 2000, CARB’s Mobile Source Emissions Model
EMFAC2000 incorporated truck idling emissions as a fac-
tor for the first time, but the data are based on limited
testing, and the emissions values derived were applied to
all vehicles, regardless of age.9
McCormick et al.8 provide a more comprehensive study
of idle emissions from 24 heavy-duty diesel vehicles (12
buses and 12 trucks) of various model years. The data were
measured on a chassis dynamometer at high altitude. The
12 diesel trucks, which ranged from 1989 to 1999 model
years, averaged 71.0 g/hr CO, 85.0 g/hr NOx, and 10.2 g/hr
total hydrocarbons (THCs). Fuel economy and CO2 emis-
sions were not reported; however, PM was measured and
averaged 1.8 g/hr for the 12 trucks. The effect of altitude
on emissions is uncertain.8 All emissions were measured
with the trucks idling under standard, factory-specified
idling speed, and the use of accessories was not reported.
Research has shown that fuel consumption during
truck idling varies as a function of engine model year,
METHODOLOGY
The U.S. Environmental Protection Agency’s (EPA) emis-
sions measurement trailer was used to measure NOx, HC,
Table 1. Fuel consumption (gal/hr) as a function of accessory horsepower demand
and engine speed.10
bhp of Accessories
rpm
0
5
10
20
30
800
0.6
0.75
1.0
0.7
1.0
1.2
1.0
1.2
1.5
1.4
1.55
1.8
1.7
2.0
1000
1200
2.25
Volume 52 September 2002
Journal of the Air & Waste Management Association 1027

Brodrick et al.
CO, and CO2 emissions under a variety of accessory load-
ings and engine speed combinations. The Emissions Char-
acterization and Prevention Branch developed EPA’s mobile
facility in 1994 for the purpose of quantifying gaseous emis-
sions as a function of truck operating parameters. The acces-
sory loadings and engine speeds were selected based on
discussions with trucking companies. The truck tested was a
1999 Freightliner Century Class truck with 450-hp engine.
Emissions data also are presented from less extensive idling
testing conducted by EPA on two 1990 and one 1989 vin-
tage tractors. The emissions estimates then are compared
with emissions rates from EPA’s emissions model (MOBILE5b)
and CARB’s emissions model (EMFAC2000). Five idling tests
(modes) were run: (1) at standard idle (600 rpm) after cruis-
ing at 55 mph for 10 min, (2) at standard idle after running
a 10-min transient cycle, (3) at standard idle with the air
conditioner in use after running a 10-min transient cycle,
(4) at high idle (1050 rpm) with the air conditioner running
after a 10-min transient cycle, and (5) at high idle with the
air conditioner running for 5 hr. For comparison purposes,
two tests were conducted with the vehicle cruising at 55
mph with and without the air conditioner running.
emission increased by 58%. The large increase in HC and
CO emissions during high engine speed and long idling
with accessories (comparing modes 3 and 5) warrants fur-
ther study of this condition, which is typical of the type of
idling that would be replaced by auxiliary power units.
Emissions while cruising at 55 mph are provided for
comparison. High idling with air conditioning (mode 4)
produces NOx emissions of ~33% of the emissions at
55-mph cruise with air conditioning (mode 7). Because
of equipment failure, only one of the repetitions was valid
for both of the 1050-rpm conditions.
Continuous Emissions Patterns
Average emissions levels provide an incomplete picture
of idling emissions. Close examination of the continuous
emissions data reveals that emissions while idling are not
steady. Thus, simple averages may be misleading. Figures
1–3 are examples of the emissions patterns observed over
time under three of the test modes.
Figure 1 is an example of the patterns observed for idling
after steady-state freeway driving at 55 mph. The emissions
pattern illustrated is for idling at 600 rpm with no accessory
load. The figure illustrates that the idling emissions begin at
~100 g/hr following freeway driving. After several minutes,
the idling emissions crept up and continued to creep up
throughout the idling testing. This indicates that the length
of idling time over which emissions are measured may af-
fect NOx emissions levels. The observed pattern could par-
tially explain the difference in emissions seen in replications
of modes 1 and 2 tests. The longer replications of these tests
had higher average emissions than the shorter replications
of the same test. This was because the longer tests had more
data subsequent to the increase in emissions. The longest
idling data collection without accessories was ~10 min, so it
is not known what the NOx emissions pattern would have
been after 10 min.
RESULTS
Reduction in Air Pollutants
and Greenhouse Gases
Emissions test results are presented in Table 2. For each
test, a minimum of three repetitions was conducted. The
average and standard deviation (SD) are presented. Exami-
nation of the EPA data reveals that, as expected, increases
in engine loading and accessory loading had significant
effects. Comparison of modes 2 and 4 indicates that rais-
ing the engine speed from 600 to 1050 rpm and turning
on the air conditioning resulted in an increase in NOx emis-
sions of ~2.5 times and a large increase in CO emissions.
HC emissions increases were unavailable because of ana-
lyzer failure. With engine speed maintained at 600 rpm,
when the air conditioner was activated (comparing modes
2 and 3), HC and CO emissions decreased slightly, but NOx
Figure 2 illustrates the trend in idling emissions fol-
lowing lower-speed transient modes typical of city driv-
ing. As with Figure 1, the emissions shown here are for a
Table 2. Emissions test results from EPA on-road testing.
HC
CO
NOx
CO2
Fuel Economy
g/hr
SD
g/hr
SD
g/hr
SD
g/hr
SD
gal/hr
SD
Mode 1: Idling after Cruising
1.8
2.9
0.3
1.0
14.6
15.9
15.3
86.0
189.7
65.1
57.4
2.3
2.0
0.6
NAb
NA
1.2
0.9
103
105
166
254
225
713
777
14
5
4034
4472
224
342
73
0.36
0.39
0.52
0.88
0.93
5.92
6.88
0.03
0.04
0.04
NA
Mode 2: Idling after Transient Cycle
Mode 3: Idling at 600 rpm with A/C
Mode 4: Idling at 1050 rpm with A/C
Mode 5: Long Idling at 1050 rpm with A/C
Mode 6: Cruise at 55 mph, no A/C
Mode 7: Cruise at 55 mph, with A/C
1.4
0.2
5
4976
a
a
NA
NA
41
51
9441
NA
86.4
5.6
NA
0.2
0.3
9743
NA
NA
60,592
60,320
1777
4072
0.14
1.40
3.9
aNot available: instrument failure; bNot applicable: only one valid test because of equipment failure.
1028 Journal of the Air & Waste Management Association
Volume 52 September 2002

Brodrick et al.
Figure 3. Idling emissions vs. time for a 1999 model year, 450-hp
engine operating at 1050 rpm with air conditioning running during a long
idling period.
Figure 1. Idling emissions vs. time for a 1999 model year, 450-hp engine
operating at 600 rpm with no accessories following cruising at 55 mph.
typical idling test at 600 rpm without accessories. In Fig-
ure 2, the emissions immediately following the transient
modes were 75 g/hr. The emissions remained at 75 g/hr
for several minutes. Then, a sudden jump in emissions
was observed. This is in sharp contrast to Figure 1, in
which emissions began at a higher level and crept up-
ward. The reason for the jump is unclear. It is not be-
lieved that any accessories, such as air compressors,
cycled on to load the engine.
Ford was run without air conditioning. The emissions test
results for these trucks, as well as the 1999 Freightliner,
are shown in Table 3. For the 1989 truck, the results rep-
resent the average of eight 4-min idling tests after tran-
sient driving with no accessory load. For the 1990 trucks,
EPA conducted 12 4-min tests after transient driving with
an accessory load. The emissions from the 1999 Freight-
liner Century Class with a 1999 engine is provided in the
last row for reference. The data for the 1999 Freightliner
are the average of three idling tests at 600 rpm with the
air conditioning running.
In Table 3, the NOx emissions from the 1999 Freight-
liner truck at standard idling with air conditioning are
slightly more than those of the 1990 Freightliner and
Kenworth trucks. HC emissions from the 1999
Freightliner are significantly lower, as are CO emissions.
Fuel economy was not measured for the 1989 and 1990
model year vehicles.
Figure 3 shows yet another pattern. This figure is an
excerpt from a 5-hr overnight idling test with air condi-
tioning running and the engine speed at 1050 rpm. For
this long idling test with accessories, a distinctive pattern
was observed. This was likely caused by the air compres-
sor periodically loading the engine. The overall emissions
level clearly is higher than in the emissions tests at 600
rpm with no accessories.
Comparison to Previous Findings
From 1996 to 1998, EPA conducted idling tests of three
older heavy-duty diesel trucks: a 1989 Ford CL-9000 with a
mechanical Cummins NTC-315 engine, a 1990 Freightliner
with an electronic Caterpillar 3176 engine, and a 1990
Kenworth with a Detroit Diesel Series 60 electronic engine.
The emissions test results are presented in this paper for
reference. The 1990 Freightliner and 1990 Kenworth tests
were run at standard idling with air conditioning, and the
Comparison of Findings to Those
in Emissions Models
Using EPA’s emissions measurements as a baseline, we
compared the emissions factors used in EPA’s and
CARB’s emissions models. Emissions estimates from
EPA’s MOBILE5b model vary based on environmental
factors, such as temperature and pressure, as well as
truck fleet characteristics, such as truck model year.
Assuming an ambient temperature of 75 ºF and the 1998
U.S. fleet characteristics in MOBILE5b, average idling
emissions for the U.S. fleet were 55.0 g/hr of NOx, 94.2
g/hr of CO, and 12.5 g/hr of HC.11 The average NOx
emissions of 55 g/hr are ~30% of the emissions meas-
ured for the 1999 Freightliner at low idle with the air
conditioning running, but they are consistent with
emissions measured on the 1989 Ford without air con-
ditioning running. In contrast, the HC and CO emis-
sions measured were much lower than predicted by
MOBILE5b.
CARB’s model, EMFAC2000, incorporates idling fac-
tors for the first time.12 They were derived from testing on
Figure 2. Idling emissions vs. time for a 1999 model year, 450-hp engine
operating at 600 rpm with no accessories following transient, city operation.
Volume 52 September 2002
Journal of the Air & Waste Management Association 1029

Brodrick et al.
Table 3. Emissions test results from EPA testing of older tractors compared with the emissions results from the 1999 Freightliner.
for the 1050-rpm condition with
the air conditioner in use would
have been expected to be 1.0 gal/
hr, assuming an air conditioner
load of 5 hp. The fuel economy was
between 0.88 and 0.93 gal/hr. Some
difference is expected because the
DOE estimates were based on data
from 1986, 1995, and 1996.
HC
CO
NOx
CO2
g/hr
SD
g/hr
SD
g/hr
SD
g/hr
SD
1989 Ford
12.4
2.6
1.0
0.4
1.3
0.2
21.6
44.6
79.3
15.3
2.3
41.1
24.8
0.6
65.7
149.3
134.6
166
6.8
22.3
36.2
5
NA
NA
NA
NA
NA
73
1990 Freightliner
1990 Kenworth
1999 Freightliner
4.9
NA
1.4
4976
Emissions on a fuel basis (g/gal)
a set of heavy-duty diesel vehicles tested by West Virginia
University. CARB did not observe differences in emissions
factors between model year, so the same emissions factors
were used for all model years.9 Idling emissions for the U.S.
fleet were 80.7 g/hr of NOx, 26.3 g/hr of CO, and 3.48 g/hr
of HC.9 These are much lower than the idling emissions
first proposed.12 As with MOBILE5b, the NOx emissions fac-
tors used in CARB’s model (80.7 g/hr) are lower than
measured on the 1999 Freightliner (103–254 g/hr NOx,
depending on engine speed and accessory load). The
EMFAC2000 NOx emissions factor is slightly higher than
our lowest emissions measurement of 65 g/hr NOx, which
was from the 1989 truck at 600-rpm idle. HC and CO emis-
sions factors were higher but more consistent with our
results for the 1999 tractor at low idle than were the
MOBILE5b factors.
are presented in Table 4. The low fuel consumption dur-
ing idling at 600 rpm resulted in very high emissions
during this condition. A second trend is that the emis-
sions difference between idling and highway operation
was much smaller than seen when emissions were com-
pared on a grams-per-hour basis. The NOx emissions in
grams per gallon while idling were at least twice as high
as emissions when the truck traveled at 55 mph in high-
way operation. The CO2 emissions in the two conditions
were similar.
CONCLUSIONS
•
•
•
Emissions and fuel consumption during truck
idling vary based on engine model year, acces-
sory loading, and engine speed.
Limited evidence also suggests that emissions
while idling may be affected by idling duration
and vehicle operation prior to idling.
CARB is currently cosponsoring the Coordinating Re-
search Council E-55/E-59, which includes collection of idling
data. EPA is sponsoring similar work. It is suggested that these
idling data be collected for a variety of model years and
engine sizes with the vehicles running under a variety of
realistic accessory loads and engine speeds.
Depending on accessory load and engine speed,
idling emissions from the 1999 truck tested ranged
between 1.4 and 86.4 g/hr HC, 14.6 and 189.7 g/
hr CO, 103 and 254 g/hr NOx, and 4034 and 9743
g/hr CO2. There is significant uncertainty in the
highest emissions levels, which were obtained
from the high idle with accesories condition.
Emissions of NOx, HC, and CO2 while idling can
be minimized by using the lowest engine speed
with the smallest accessory load.
Fuel Economy Results
Fuel consumption was calculated and found to be rea-
sonably consistent with that recorded by the engine com-
puter. The fuel consumption for the 1999 tractor was
lower than the fuel consumption estimates generated by
the DOE (see Table 1). Based on Table 1, fuel economy
•
•
At engine speeds of 1050 rpm with air condition-
ing, idling produces NOx emissions (g/hr) of ~33%
of the emissions generated while cruising at 55
mph with air conditioning.
Table 4. Emissions test results from EPA on-road testing on a fuel basis.
HC
CO
NOx
g/gal
CO2
g/gal
•
Cycling of the accessory loads, such as compres-
sors, results in fluctuations in emissions levels
over time. This contributes to the variation in
emissions between test replications.
g/gal
g/gal
Mode 1: Idling after Cruising
5.0
7.4
41
40
31
98
204
11
9
292
267
335
287
242
120
116
11,369
11,336
10,037
10,678
10,476
10,232
8975
Mode 2: Idling after Transient Cycle
Mode 3: Idling at 600 rpm with A/C
Mode 4: Idling at 1050 rpm with A/C
2.9
ACKNOWLEDGMENTS
a
We would like to thank Edward Brown and Matt Clayton
of ARCADIS Geraghty and Miller for their data collection
and processing assistance. We would like to thank Jenny
Tang, Nicolas Lutsey, and Renee Pearl of ITS-Davis for
their valuable contributions. We would also like to thank
Mode 5: Long Idling at 1050 rpm with A/C 92.9
Mode 6: Cruise at 55 mph, No A/C
Mode 7: Cruise at 55 mph, with A/C
1.0
0.6
aNot available: instrument failure.
1030 Journal of the Air & Waste Management Association
Volume 52 September 2002

Brodrick et al.
11. Mobile5b Vehicle Emission Modeling Software; U.S. Environmental Pro-
tection Agency, Office of Transportation Air Quality: Washington,
DC, 1997.
12. Public Meeting to Consider Approval of Revisions to the State’s On-Road
Motor Vehicle Emissions Inventory; Technical Support Document; Cali-
fornia Air Resources Board: Sacramento, CA, 2000.
Archana Agrawal and Hector Maldonado of California Air
Resources Board for their review of this paper. Funding
for this work was provided in part by the University of
California Transportation Research Center, the National
Science Foundation IGERT Program, and the Dwight D.
Eisenhower Fellowship Program.
REFERENCES
1. Stodolsky, F.; Gaines, L.; Vyas, A. Analysis of Technology Options to
Reduce the Fuel Consumption of Idling Trucks; ANL/ESD-43; Argonne
National Laboratory: Argonne, IL, 2000.
2. Brodrick, C.J.; Farshchi, M.; Dwyer, H.A.; Gouse, S.W.; Mayenburg,
M.; Martin, J. Demonstration of a Proton-Exchange Membrane Fuel
Cell as an Auxiliary Power Source for Heavy Trucks. SAE Technical
Paper 2000-01-3488; Society of Automotive Engineers: Warrendale,
PA, December 2000.
About the Authors
3. Van den Berg, A.J. Truckstop Electrification: Reducing CO Emissions
from Mobile Sources While They are Stationary; Energy Co2nvers. Man-
age. 1996, 37 (6-8), 879-884.
4. Jones, R. Powering Up for Comfort; Landline Mag. 1999.
5. Abrams, F. Fuel Economy Savings; American Trucking Association’s Fleet
Owner Mag. 2000, May.
6. Carl Moyer Program Annual Status Report; California Air Resources Board:
Sacramento, CA, March 26, 2002.
7. Texas Administrative Code. Control Requirements for Motor Vehicle
Idling, Rule 114.502; January 18, 2001.
8. McCormick, R.L.; Graboski, M.S.; Alleman, T.L.; Yanowitz, J. Idle Emis-
sions from Heavy-Duty Diesel and Natural Gas Vehicles at High Alti-
tude; J. Air & Waste Manage. Assoc. 2000, 50 (11), 1992-1998.
9. Maldonado, H.; Agrawal, A. California Air Resources Board, Sacra-
mento, CA. Personal communication, February 11, 2002.
10. Don’t Idle Your Profits Away; Brochure; U.S. Department of Energy,
Office of Heavy Vehicle Technologies: Washington, DC, 1999.
Christie-Joy Brodrick (corresponding author; e-mail:
cjbrodrick@aol.com) is a researcher at the Institute of Trans-
portation Studies, University of California–Davis (ITS-Davis).
Harry A. Dwyer, professor of mechanical and aeronautical
engineering, leads the heavy-vehicle research group at ITS–
Davis. Mohammad Farshchi, now with Sharif University of
Technology, Tehran, Iran, was a researcher at ITS-Davis dur-
ing the preparation of this paper. D. Bruce Harris has 30 years’
experience in emissions controls and measurements with the
air pollution control technology group at EPA. Foy G. King,
Jr., also with EPA, specializes in auto and truck emissions.
Volume 52 September 2002
Journal of the Air & Waste Management Association 1031