The Cost-Effectiveness of Heavy-Duty
Diesel Retrofits and Other Mobile
Source Emission Reduction
Projects and Programs
United States
Environmental Protection
Agency
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The Cost-Effectiveness of Heavy-Duty
Diesel Retrofits
and
Other Mobile Source Emission
Reduction Projects and Programs
Transportation and Regional Programs Division
Office of Transportation and Air Quality
U.S. Environmental Protection Agency
v>EPA
United States EPA420-B-07-006
Environmental Protection .. .,
Agency MaY2007
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Introduction
The Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users
(SAFETEA-LU) was enacted August 10, 2005, as Public Law 109-59. SAFETEA-LU creates
new opportunities as well as responsibilities for States, Metropolitan Planning Organizations
(MPOs), and other agencies involved in the selection of projects funded through the Congestion
Mitigation and Air Quality Improvement Program (CMAQ). Among the changes, Section 1808
of SAFETEA-LU, for the first time, makes CMAQ funding available for many nonroad diesel
retrofits for nonroad vehicles, engines, and construction equipment that are used on Title 23
projects in certain nonattainment areas. While acknowledging State and MPO roles and authority
for making final project selections, Section 1808 also addresses funding priority. "(A) IN
GENERAL - States and metropolitan planning organizations shall give priority in distributing
funds received for congestion mitigation and air quality projects and programs from
apportionments derived from applications of sections 104(b)(2)(B) and 104(b)(2)(C) to - (i)
diesel retrofits, particularly where necessary to facilitate contract compliance, and other cost-
effective emission reduction activities, taking into consideration air quality and health effects;
and (ii) cost-effective congestion mitigation activities that provide air quality benefits. (B)
SAVINGS - This paragraph is not intended to disturb the existing authorities and roles of
governmental agencies in making final project selections."
To support the implementation of Section 1808, Congress included a provision for the EPA, in
consultation with DOT, to publish information on diesel retrofit technologies that have been: 1)
certified or verified by EPA or the California Air Resources Board (CARB)1; 2) identified by
EPA or CARB as having an application and approvable test plan for verification; and 3) other
available information regarding the emission reduction effectiveness and cost-effectiveness of
diesel emission control technologies, taking into consideration air quality and health effects.2
In addition, The Energy Policy Act of 2005 (EPACT), enacted as Public Law 109-58 includes a
Diesel Emissions Reduction Program that authorizes funding to establish cost-effective clean
diesel projects.3 This document will assist eligible entities with designing and implementing
projects and will fulfill EPA's obligation under EPACT to provide information regarding the
cost-effectiveness of eligible technologies for reducing emissions.4
EPA is issuing this document in fulfillment of these statutory requirements. States and local
agencies involved with developing and implementing air pollution control programs should
consult this information when making choices about investments to achieve air quality and
public health goals. This document does not substitute for any applicable regulations, nor is it a
regulation itself. It does not impose binding, enforceable requirements on any party and may not
apply to a particular situation based upon the circumstances. EPA and State decision makers, as
1 For a complete list of all EPA verified technologies, consult the list at the following web site:
http://www.epa.gov/otaq/retrofit/retroverifiedlist.htm Information on CARB's verification program can be accessed
at: http://www.arb.ca.gov/diesel/verdev/verdev.htm."
2 23 U.S.C. Section 149(f)(2)
3 The Diesel Emissions Reduction program can be found in Subtitle G of the Energy Policy Act of 2005. Section
792(c)(3) specifies cost effectiveness as a priority for evaluating projects.
4 Section 793(b)(l)(C)
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well as other interested parties are free to raise questions about the applicability of this
information to a particular situation. The information in this document may be revised
periodically without public notice as new data and research becomes available.
Background
In previous transportation legislation, Congress required the National Academy of Sciences
(NAS) to evaluate the CMAQ Program. The results of the NAS CMAQ study demonstrate that
certain CMAQ eligible activities can be far more cost-effective in generating emission
reductions than others.5 Furthermore, implementation of the 8-hour ozone and fine particulate
matter (PM2 5) National Ambient Air Quality Standards (NAAQS) underscores a need, in some
areas, to identify additional local emission reduction activities that can help nonattainment areas
meet the earliest of the NAAQS attainment dates (2010).
Retrofit projects can begin producing emission reductions immediately and can help State and
local governments reduce emissions of PM2.5, nitrogen oxides (NOx), and volatile organic
compounds (VOC) in the near term. Retrofits include a wide range of emission reduction
strategies available for diesel vehicles and equipment, including:
Retrofitting engines with verified technologies
Using cleaner fuels
Replacing older equipment
Repowering (replacing old engines with new, cleaner engines
Reducing idling
Properly maintaining equipment
Gaining operational efficiencies
Retrofit technologies are advancing at a rapid pace. The use of established technologies, such as
diesel oxidation catalysts (DOCs) and diesel particulate filters (DPFs), continues to grow
exponentially, while new, emerging technologies such as Lean NOx (LNC) catalysts, are
steadily improving. Retrofit technologies often vary in the type of pollutant reduced. DOCs and
DPFs remove PM from the exhaust, but do not reduce NOx. However, DOCs or DPFs can be
combined with a NOx reduction strategy - such as a cleaner fuel - to enhance the emission
reduction benefits.
While retrofit technologies are one option for reducing diesel emissions, other options include
cleaner fuels such as compressed natural gas (CNG) and the replacement of older engines and
equipment. Cleaner fuels are becoming more prevalent throughout the country. The switch to
ultra-low sulfur diesel (ULSD) fuel for highway engines enables advanced emissions reduction
technologies to operate effectively (e.g. DPFs). Another option that can be applied to any
vehicle or equipment is to reduce idling. Simply turning off the engine when the vehicle or
Transportation Research Board. The Congestion Mitigation and Air Quality Improvement Program: Assessing 10
Years of Experience. Special Report 264. Washington, D.C.: 2002.
2
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machine is not in use can reduce emissions as well as save fuel and minimize wear and tear on
the engine.
As described below, diesel retrofits are especially important in areas facing immediate
challenges to reduce PM2.5 emissions and minimize the health impacts of diesel exhaust on its
citizens. Some retrofits can provide benefits in the near-term by accelerating the use of new
emission reduction technologies on existing older vehicles and engines. Otherwise, these
vehicles and engines would continue emitting at higher rates throughout their useful lives. Given
their immediate benefits, State and local agencies should work together to determine how retrofit
projects could best be used, given local air quality characteristics. One option is to re-evaluate
the programming of CMAQ funds with an emphasis on supporting PM2 5 emission reduction
strategies that can cost-effectively help areas attain the PM2.5NAAQS in 2010, reduce PM2.5
health risks and meet their transportation conformity requirements.6
While SAFETEA-LU emphasizes eligibility and priority funding for retrofits, it is important to
note that the CMAQ program is not the only funding resource available to support retrofit
programs. Collaborations of federal, state, and local government agencies, nonprofit
organizations, and industry, are working together to fund retrofit projects across the country.
Information about these collaboratives and funding opportunities are available at:
http ://www. epa. gov/cleandiesel/grantfund.htm
Health Impacts
Reducing emissions from diesel engines is one of the most important public health challenges
facing the country. EPA recently finalized two sets of clean fuel and vehicle emissions standards
that will lead to dramatic emission reductions in new diesel-powered engines. Included within
these rulemakings are cleaner fuel requirements, such as the use of ultra-low sulfur diesel, which
will provide immediate emissions reductions in both new and older diesel engines.
Even with more stringent heavy-duty highway and nonroad engine standards set to take effect
over the next decade, millions of diesel engines already in use will continue to emit large
amounts of PM2 5 emissions, which contribute to serious public health problems. These
emissions cause thousands of premature deaths, hundreds of thousands of asthma attacks,
millions of lost work days, and numerous other health impacts every year. There are almost 65
million people living in 120 counties with monitored PM2 5 levels (2000-2002) exceeding the
PM2.5 NAAQS.
Diesel engines emit large amounts of nitrogen oxides and particulate matter. In 2004, diesel
engines produced more than 6.2 million tons of NOxand more than 300,000 tons of PM25.
Highway diesel engines accounted for approximately 50% of NOX and 30% of PM2 5 from the
mobile source diesel sector. The freight sector's contribution to diesel emissions - which
included rail movement for the first time in 2004 - was approximately 56% of NOX and 32% of
PM25. Nonroad equipment accounted for 24% of NOX and almost half of diesel PM25 emissions
6 On October 31, 2006, the U. S. Department of Transportation issued interim guidance for the CMAQ Program as
reauthorized under SAFETEA-LU. This document is available electronically at
http://www.fhwa.dot.gov/environment/cmaq06gm.htm
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in 2004. While marine engines account for only 3% of diesel engines in 2004, port and non-port
related marine emissions accounted for 16% of NOX and 14% of PM of all mobile diesel sources.
EPA believes that diesel exhaust is likely to be carcinogenic to humans. The risk associated with
exposure to diesel exhaust includes the particulate and gaseous components among which are
benzene, formaldehyde, acetaldehyde, acrolein, and 1,3-butadiene, all of which are known or
suspected human or animal carcinogens, or have noncancer health effects.7 Specifically diesel
exhaust has been judged to pose a lung cancer hazard for humans as well as a hazard from
noncancer respiratory effects such as pulmonary inflammation. EPA assessed air toxic emissions
and their associated risk (the National-Scale Air Toxics Assessment or NATA for 1999), and we
concluded that diesel exhaust ranks with other substances that the national-scale assessment
suggest pose the greatest relative risk.
Health effects associated with short-term variation in ambient PM have been indicated by
epidemiologic studies showing associations between exposure and increased hospital admissions
for ischemic heart disease, heart failure, respiratory disease, including chronic obstructive
pulmonary disease (COPD) and pneumonia. Short-term elevations in ambient PM have also been
associated with increased cough, lower respiratory symptoms, and decreases in lung function.
Additional studies have associated changes in heart rate and/or heart rhythm in addition to
changes in blood characteristics with exposure to ambient PM. Short-term variations in ambient
PM have also been associated with increases in total and cardiorespiratory mortality.8 Children
are especially sensitive to diesel emissions compared to healthy adults because their respiratory
systems are still developing and they have a faster breathing rate. Areas that are attaining the
PM2.5 standard may wish to consider these factors when planning on how to effectively remain in
attainment and protect the public health.
Diesel exhaust also contributes to the formation of ground level ozone. While much has been
accomplished in reducing ozone levels, ground-level ozone remains a pervasive pollution
problem in many areas of the United States. Exposure to ozone has been linked to a number of
health effects, including significant decreases in lung function, inflammation of the airways, and
increased respiratory symptoms, such as cough and pain when taking a deep breath. Exposure
can also aggravate lung diseases such as asthma, leading to increased medication use and
increased hospital admissions and emergency room visits. Active children are the group at
highest risk from ozone exposure because they often spend a large part of the summer playing
outdoors. Children are also more likely to have asthma, which may be aggravated by ozone
exposure. Other at-risk groups include adults who are active outdoors (e.g., some outdoor
7 U.S. EPA (2002) Health Assessment Document for Diesel Engine Exhaust. EPA/600/8-90/057F Office of
Research and Development, Washington DC. This document is available electronically at
http ://cfpub. epa. gov/ncea/cfm/recordisplav. cfm?deid=29060
8 U.S.EPA (1996) Air Quality Criteria for Particulate Matter, EPA 600-P-95-001aF, EPA 600-P-95-001bF. This
document is available in Docket EPA-HQ-OAR-2005-0036. U.S. EPA (2004) Air Quality Criteria for Particulate
Matter (Oct 2004), Volume I Document No. EPA600/P-99/002aF and Volume II Document No. EPA600/P-
99/002bF. This document is available in Docket EPA-HQ-OAR-2005-0036. U.S. EPA (2005) Review of the
National Ambient Air Quality Standard for Particulate Matter: Policy Assessment of Scientific and Technical
Information, OAQPS Staff Paper. EPA-452/R-05-005. This document is available in Docket EPA-HQ-OAR-2005-
0036.
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workers) and individuals with lung diseases such as asthma and chronic obstructive pulmonary
disease. In addition, long-term exposure to moderate levels of ozone may cause permanent
changes in lung structure, leading to premature aging of the lungs and worsening of chronic lung
disease.9
Ozone also affects vegetation and ecosystems, leading to reductions in agricultural crop and
commercial forest yields, reduced growth and survivability of tree seedlings, and increased plant
susceptibility to disease, pests, and other environmental stresses (e.g., harsh weather). In long-
lived species, these effects may become evident only after several years or even decades and
may result in long-term effects on forest ecosystems. Ground level ozone injury to trees and
plants can lead to a decrease in the natural beauty of our national parks and recreation areas.
Cost-Effective Emission Reduction Activities
Cost-effectiveness, for the purpose of this document, is defined as the cost per ton of emissions
reduced. Within this context, cost-effectiveness can vary depending on a number of factors. The
pollutant(s) for which the area is in nonattainment, precursor pollutants of concern, relative size
of pollutant inventories, and the existing sources and level of control measures in place can all
influence cost-effectiveness. It is also important to note that cost-effectiveness does not
necessarily correspond with overall effectiveness. For instance, a certain project or technology
may be very cost-effective at reducing VOCs in an ozone nonattainment area, but if the project
or technology only applies to very few emissions sources, or if the air quality chemistry in the
ozone nonattainment area is NOx dependant, the overall effectiveness in reducing ozone may be
quite limited.
Where essential emission reductions are more difficult to achieve, the acceptable cost of
achieving those reductions could increase. Areas with more serious air quality problems
typically will need to obtain greater levels of emissions reductions from local sources than areas
with less serious problems, and it would be expected that their residents could realize greater
health benefits from such reductions. It may be reasonable and appropriate for areas with more
serious air quality problems to fund emission reduction requirements with generally higher costs
per ton than the cost of emissions reductions in areas with less serious air quality problems.
Given these considerations, EPA believes that it is not necessary to propose a fixed dollar per ton
cost threshold for identification of cost-effective emission reduction activities.
Retrofitting diesel engines is, however, one of the most cost-effective ways to reduce diesel
emissions. The term diesel retrofit includes any technology or system that achieves emission
reductions beyond that required by the EPA regulations at the time of new engine certification.
Diesel retrofit projects include the replacement of high-emitting vehicles/equipment with cleaner
vehicles/equipment (including hybrid or alternative fuel models), repowering or engine
replacement, rebuilding the engine to a cleaner standard, the purchase and installation of
9 U.S. EPA. Air Quality Criteria for Ozone and Related Photochemical Oxidants (Final). U.S. Environmental
Protection Agency, Washington, DC, EPA/600/R-05/004aF-cF, 2006. This document is available at:
http://www.epa.gOv/ttn/naaqs/standards/ozone/s o3 cr cd.html
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advanced emissions control technologies (such as particulate matter traps or oxidation catalysts)
or the use of a cleaner fuel. For example, diesel oxidation catalysts can result in a per vehicle
particulate matter reductions of 20-40%. Diesel particulate filters reduce particulate matter up to
90% per vehicle.
To help stakeholders identify cost-effective technologies, EPA has developed a list of verified
retrofit technologies that contains information on expected emission reduction benefits. This list
provides information on numerous innovative emission control technologies that EPA has
approved for receiving emission reduction credit. Each EPA verified technology has undergone
extensive testing and analysis. The verification process includes evaluations of the emissions
reduction performance of retrofit technologies- including the durability of the technologies- and
identification of engine operating criteria and other conditions that must exist for these approved
technologies to achieve the verified level of reductions. EPA evaluates each technology using a
specific fuel, on a specific engine, and under specific loading cycles. The California Air
Resources Board (CARB) has a verification process similar to EPA's verification process. EPA
has signed a Memorandum of Agreement with CARB to recognize CARB's list of verified
emission control options.10 In addition, EPA has established a comprehensive list of idle-control
technologies, which is available on the EPA website.11
To help stakeholders compare cost-effective strategies, EPA has included an appendix with 4
tables containing estimates of the cost per ton of pollutant reduced, for projects and programs
that are potentially eligible for CMAQ funding. The estimates are derived from the best data
available to EPA at the time this document was issued. The source of the information is
identified for each project category.
The tables include cost-effectiveness estimates for reducing NOx and VOC precursor emissions
for ozone and for PM emissions. As noted above, it is not always constructive to do a direct
comparison between the cost-effectiveness of reducing different pollutants. For instance, PM
and NOx cost-effectiveness are not comparable because the health effects, emissions inventories
and control sources for the two pollutants are very different. Generally, emissions inventories
show much greater amounts of NOx compared to PM. Correspondingly, greater reductions of
NOx emissions are required to reduce ambient ozone levels than reductions of PM emissions
required to reduce ambient PM levels. While reducing a ton of PM often costs more than to
reduce a ton of NOx, the health effects of PM are greater per ton than for NOx. In addition to
assessing the cost-effectiveness of reducing a pollutant, careful consideration should be given to
the overall effectiveness of the reductions. Due to the greater health hazard posed by PM, a little
PM reduction may be more effective than larger NOx reductions from a public health
perspective.
Table 1 summarizes PM cost-effectiveness for typical diesel retrofit scenarios that utilize a diesel
oxidation catalyst (DOC) or catalyzed diesel particulate filter (CDPF). These cost-effectiveness
10 For a complete list of all EPA verified technologies, consult the list at the following web site:
http://www.epa.gov/otaq/retrofit/retroverifiedlist.htm. The MO A can also be found at this web site.
1: A list of idle-control technologies can be found at: http://www.epa.gov/otaq/smartwav/idlingtechnologies.htm
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estimates have not factored in the co-benefits from reducing other pollutants such as VOC. The
cost-effectiveness of retrofitted programs can vary significantly depending on a number of
factors, including actual annual average activity (i.e., annual vehicle miles traveled for highway
or annual operating hours for nonroad). Table 2 is similar to Table 1 and contains PM cost-
effectiveness for typical nonroad retrofit projects utilizing a diesel oxidation catalyst (DOC) or
catalyzed diesel particulate filter (CDPF). More information about the data and the methodology
used to develop these tables is in EPA's technical report entitled "Diesel Retrofit Technology:
An Analysis of the Cost Effectiveness of Reducing Particulate Matter Emissions from Heavy-
Duty Diesel Engines Through Retrofits." This report can be found at:
http://www.epa.gov/cleandiesel/publications.htm
Table 3 summarizes the cost-effectiveness of some specific voluntary mobile source emission
reduction programs supported by EPA's Office of Transportation and Air Quality. These
voluntary programs aim to achieve cost-effective emission reductions without the need for
regulation. These programs are implemented through partnerships with small and large
businesses, citizen groups, industry, manufacturers, trade associations, and state and local
governments. More information about these programs can be found at:
http ://epa. gov/otaq/voluntary. htm
Table 4 contains project and program categories taken from the study by the NAS in 2002. The
NAS CMAQ study assessed the cost-effectiveness of various CMAQ-eligible strategies to
reduce emissions. The study estimated the cost-effectiveness of projects based on cost (in
calendar year 2000 dollars) per ton of emissions (VOC and NOx) reduced. To bring the cost
estimates current, EPA adjusted the NAS's estimates to 2006 dollars according to the consumer
price index established by the Bureau of Labor Statistics, U.S. Department of Labor.
Recognizing that ozone levels in many nonattainment areas are more dependant on NOx than on
VOCs, and consistent with the NAS methodology, the Table 4 estimates assume a benefit
weighting ratio of 4:1 for NOx: VOC. This approach to weighting is commonly used to calculate
one cost-effectiveness value for multiple pollutant reductions. The weighting factors are
determined on the basis of relative damage values of the individual pollutants. The damage value
of a given pollutant is estimated through modeling of air quality, assessing human and
environmental exposure, and then applying a valuation to the health and environmental effects of
the exposure.
It is important to note that while the estimates reflect the best available data at the time, there are
limitations inherent in such an assessment. The data presented are based on a select sampling of
projects that may not completely capture the potential cost-effectiveness of other techniques of
implementing particular strategies. Therefore, the median cost should be considered along with
the cost range to better portray a project's potential cost-effectiveness. Further analysis is
recommended in order to assess the cost-effectiveness and emission reduction potential of
specific projects or programs. EPA provides models for estimating the transportation sector's
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impacts on emissions. Emissions estimates from these models can be used for evaluating the
impact and cost-effectiveness of various emissions control strategies.
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National Ambient Air Quality Standards
Consistent with the statutory provisions of SAFETEA-LU regarding CMAQ funding priority for
diesel retrofits, implementation of the NAAQS for PM2.5 and 8-hour ozone also highlights the
critical need to target CMAQ funds to diesel engine retrofits and the most cost-effective
emission reduction activities. While substantial emission reductions have been achieved in the
mobile source sector, recent data show that mobile sources remain a major source of air pollution
in most nonattainment areas.13
Many States and MPOs with PM2.5 nonattainment areas face a unique challenge in that their
CMAQ funds have been previously allocated to support attainment of the ozone NAAQS.
The initial statutory attainment date for the current PM2.5 NAAQS is as expeditiously as practical
but no later than 2010 and emission reductions needed to attain the standard must be in place at
the beginning of 2009.14 States are required to submit PM2.5 state implementation plans (SIPs) in
2008 to demonstrate how the nonattainment areas will attain the PM2.5 NAAQS. Therefore, it is
particularly urgent that States and MPOs in PM2.5 areas begin now to direct CMAQ resources to
the control of diesel emissions.
States and MPOs in 8-hour ozone nonattainment areas should also consider how CMAQ
resources can be used to fund retrofit projects and other cost-effective measures to help attain the
8-hour ozone NAAQS. Eight-hour ozone nonattainment areas have varying attainment dates
depending on the level of their ozone concentrations. Some areas may need to implement local
control measures to achieve emission reduction in advance of the timeframe for emission
reductions projected to be achieved by national control measures. States and MPOs are also
required to meet the transportation conformity requirements of section 176(c) of the CAA.
Transportation conformity ensures that emissions that result from an area's transportation system
stay within the limits established in the SIP. In some PM2.5 and 8-hour ozone areas, staying
within these emissions limits may necessitate additional controls, potentially including diesel
emission reduction strategies.
On September 21, 2006, EPA issued new standards which strengthen the 24-hour PM2.5
standard. EPA anticipates that attainment (meeting the standards) and nonattainment (violating
the standards) designations for areas with respect to the new standard will become effective in
12 For more information, see: http://www.epa.gov/otaq/models.htm and
http://www.epa.gov/omswww/stateresources/tools.htm EPA has also recently released a quantification tool for
estimating environmental impacts and cost effectiveness of emissions reduction technologies added to vehicles and
equipment. The Diesel Emissions Quantifier can be accessed at: http://cfpub.epa.gov/quantifier/
13 See the EPA Clearinghouse for Inventories and Emissions Factors - 2002 National Emissions Inventory Data and
Documentation, http://www.epa.gov/ttn/chief/net/2002inventory.html
14Because the current PM2 5 designations were effective in 2005, areas must demonstrate attainment as expeditiously
as practical but no later than 2010. However, Clean Air Act section 172 (a)(2)(A) allows areas to request that the
attainment date be extended by up to five additional years if they can justify the need for such an extension based on
the severity of the nonattainment problem and the availability and feasibility of control measures.
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April 2010.15 States with nonattainment areas must submit plans by April 2013 to demonstrate
how they will attain the standards by 2015. While the most pressing need for the states is to
develop local measures to meet the current PM2 5 standard, the further tightening of the PM2 5
standard and the retention of the 24-hour coarse PM standard may create an additional need for
reductions in the period from 2010 to 2015.
For these reasons, EPA strongly recommends that States and MPOs re-evaluate their current and
proposed transportation plans and CMAQ activities to ensure an appropriate balance in projects
to support attainment of the PM2.5 and 8-hour ozone NAAQS.
EPA Emission Reduction Guidance and Cost Effectiveness Resources
EPA, in consultation with DOT and stakeholders, has developed several guidance documents to
help MPOs and others take emission reduction credit for CMAQ (or other) funded activities that
retrofit diesel engine trucks, nonroad equipment (such as construction and locomotives), school
buses, reduce idling from diesel trucks, and support strategies to reduce drive-alone commutes.
In addition, EPA has released quantification tools for estimating the environmental impacts and
cost effectiveness of emission reduction technologies to vehicles and equipment. These
documents and resources are:
U.S. EPA. Diesel Retrofits: Quantifying and Using Their Benefits in SIPs and
Conformity. Guidance for State and Local Air and Transportation Agencies. EPA420-B-
06-005. http://www.epa.gov/otaq/stateresources/transconf/policy/420b06005.pdf
U.S. EPA. Guidance for Quantifying and Using Long-Duration Truck Idling Emission
Reductions in State Implementation Plans and Transportation Conformity. EPA420-B-
04-001. January 2004. http://www.epa.gov/smartway/idle-guid.htm
U.S. EPA. The Diesel Emissions Quantifier (DEQ). This on-line interactive tool
estimates the emissions reductions of clean diesel projects and their cost effectiveness.
Accessible at: http://www.epa.gov/cleandiesel/
U.S. EPA. National Mobile Inventory Model. This model estimates emissions from
highway vehicles and nonroad equipment. Accessible at:
http ://www. epa. gov/otaq/nmim.htm
U.S. EPA. Smartway Technology Package Savings Calculator. This calculator is
designed to help truck owners compare the costs and estimate the fuel savings associated
with various efficiency technologies. Accessible at:
http ://www. epa. gov/smartway/calculator/loancalc.htm
15 Clean Air Act section 107(d)(l)(B) requires EPA to promulgate designations within two years of the
promulgation or revision of a NAAQS. However, this time period may be extended for up to one year if there is
insufficient information to promulgate the designations.
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U. S. EPA. Guidance for Quantifying and Using Emission Reductions from Best
Workplaces for Commuter Programs in State Implementation Plans and Transportation
Conformity. EPA420-B-05-016. October 2005.
http ://www. epa. gov/otaq/stateresources/policy/transp/commuter/420b07015 .pdf
U.S. EPA. Diesel Retrofit Technology: An Analysis of the Cost Effectiveness of Reducing
Particulate Matter Emissions from Heavy-Duty Diesel Engines Through Retrofits.
EPA420-S-06-002. March 2006. http://www.epa.gov/cleandiesel/publications.htm
U.S. EPA. Diesel Retrofit Technology: An Analysis of the Cost Effectiveness of Reducing
Particulate Matter and Nitrogen Oxides Emissions from Heavy-Duty Nonroad Diesel
Engines Through Retrofits. EPA420-R-07-005. May 2007.
http://www.epa.gov/cleandiesel/publications.htm
U.S. EPA. Guidance for Quantifying and Using Long-Duration Switch Yard Locomotive
Idling Emission Reductions in State Implementation Plans. EPA420-B-04-002. January
2004. http://www.epa.gov/smartway/idle-guid.htm
EPA has prepared these documents and resources to help States and MPOs estimate emission
benefits. The guidance documents address how to take credit for them in SIPs and conformity
determinations. These activities can be incorporated into the SIP as mandatory measures or as a
voluntary mobile source measure as appropriate. Additional guidance documents and other
information resources from EPA's Office of Transportation and Air Quality are available at:
www. epa. gov/otaq
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APPENDIX
Table 1. Summary of Cost-Effectiveness for Various Diesel PM Retrofit Scenarios
Vehicle
School Bus
Class 6&7
Truck
Class 8b
Truck
250 hp
Bulldozer
Retrofit Technology*
DOC
CDPF
DOC
CDPF
DOC
CDPF
DOC
CDPF
Range of $/ton PM Emission Reduced**
$12,000
$12,400
$27,600
$28,400
$11,100
$12,100
$18,100
n/a
$49,100
$50,500
$67,900
$69,900
$40,600
$44,100
$49,700
n/a
* Retrofit technologies include diesel oxidation catalyst (DOC) and catalyzed diesel paniculate filter (CDPF)
** The cost per ton of PM reduced will depend on a variety of factors including the age and activity levels of the
vehicles or equipment. Source: U.S. EPA. Diesel Retrofit Technology: An Analysis of the Cost Effectiveness of
Reducing Particulate Matter Emissions from Heavy-Duty Diesel Engines Through Retrofits. EPA420-S-06-002.
March 2006. http://www.epa.gov/cleandiesel/publications.htm
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APPENDIX
Table 2. Summary of Cost-Effectiveness for Various Nonroad Diesel PM Retrofit Scenarios
Equipment
Off-highway trucks
Loaders/B ackhoe s/Tractors
Excavators
Cranes
Generator Sets
Retrofit
Technology*
DOC
CDPF
DOC
CDPF
DOC
CDPF
DOC
CDPF
DOC
CDPF
Range of $/ton of PM Reduced**
$21,700
$24,200
$25,900
$28,800
$22,300
$24,800
$20,900
$23,300
$18,700
$20,800
$78,800
$87,600
$49,900
$55,400
$61,900
$68,800
$60,000
$66,700
$46,100
$51,300
* Retrofit technologies include diesel oxidation catalyst (DOC) and catalyzed diesel paniculate filter (CDPF)
** The cost per ton of PM reduced will depend on a variety of factors including the age and activity levels of the
vehicles or equipment. Source: U.S. EPA. Diesel Retrofit Technology: An Analysis of the Cost Effectiveness of
Reducing P articulate Matter and Nitrogen Oxides Emissions from Heavy-Duty Nonroad Diesel Engines Through
Retrofits. EPA420-R-07-005. May 2007. http://www.epa.gov/cleandiesel/publications.htm
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APPENDIX
Table 3. Summary Cost-Effectiveness of EPA Voluntary Mobile Source Programs (4:1 weighting of NOx;VOC)
Activity
Advanced Truck
Stop
Electrification
Truck Auxiliary
Power Units
Diesel Retrofits
Best Workplaces
for Commuters
Description
Advanced truck stop electrification provides a parked truck with
electrical power, and heating, cooling, and other amenities like
telecommunication hook ups, through an external console that fits
into the truck's window frame.
An APU consists of a small engine and generator that provides power
to the truck when the main engine is shut off. It power s heating, air
conditioning, and electrical accessories for the cab and sleeper.
Examples of diesel retrofits include engine upgrades, engine
repowers or replacements, cleaner fuels, emissions control
technologies, or idle controls.
Best Workplaces for Commuters is a voluntary business-
government program that distinguishes and provides national
recognition to employers offering outstanding commuter benefits
such as free or low cost bus passes, strong telework programs,
carpooling matching and vanpool subsidies, www.bwc.gov
Median
Cost
$1,700
$3,100
$5,950*
$19,200
Cost Range
$1,400
$2,700
$1,900*
$19,200
$2,000
$3,500
$19,000*
$19,200
Sources
1
2
3
4
Sources: (l)NOx emission factor based on EPA engine idling testing (see http://www.epa.gov/smartwav/idle-guid.htm'): assumes activity level of 40%-50% (or
9.6 -12 hours/day) utilization of one electrified parking space over 365 days/year (06/28/06 interview, Tom Badgett, Chief Information Officer, IdleAire
Technologies, Inc.; assumes 20 year service life (06/26/06 interview, Tom Badgett); assumes $17K per space (see Texas A&M Research Foundation, Request for
Proposals #6001498, http://rf-web.tamu.edu/'); (2)Assumes 2,000 hour/year usage (interview with 3 leading APU manufacturers - Teleflex/Carrier, Rig Master,
Thermo King; assumes NOx offset from APU at 23 g/hr (see http://www.epa.gov/smartwav/idle-guid.htm; assumeslO year service life (interview with APU
manufacturers); assumes $7K per unit (see American Transportation Research Inst. RFP #3-14-1104). (3) NOx reduction based on applying the methodology
outlined in the technical paper "Diesel Retrofit Technology: An Analysis of the Cost-Effectiveness of Reducing F'articulate Matter Emissions from Heavy-Duty
Diesel Engines Through Retrofits" to a select group of NOx reducing retrofit technologies. The cost per ton of NOx reduced will depend on a variety of factors
including the age and activity levels of the vehicles or equipment and the technology utilized. These cost figures only account for NOx reductions and do not
factor in VOC reductions. Consequently, the 4:1 NOx: VOC weighting does not apply. (4) Best Workplaces for Commuters: E.H. Pechan and Associates, Inc.,
PM NAAQS Mobile Modeling Technical Memorandum. Prepared for U.S.EPA. July 2006.
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APPENDIX
Table 4. Cost-Effectiveness of Various Mobile Source Projects (4:1 weighting of NOx:VOC)
Activity
Inspection and Maintenance
Regional Rideshare
Vanpool Programs
Travel Demand Management
Conventional Fuel Bus
Replacement
Alternative Fuel Non-Transit
Vehicles
Traffic Signalization
Description
Typically pays for the operating expenses of I&M programs
Regional rideshare programs provide marketing, administrative and
limited operating costs for area-wide carpool and ridesharing
programs.
Similar to regional rideshare but focused on support and promotion
ofvanpools.
Usually informational and promotional programs administered by
governments, public agencies and public-private partnerships.
Often implemented at the employer level, utilizing ridesharing,
transit and parking strategies
Replace pre-1991 model year diesel buses with post- 1996 diesel
buses. Emission reductions and cost-effectiveness decrease rapidly
if replacing newer buses
Electric, CNG, LPG Vehicles and fueling facilities
Traffic signal inter-connection and timing optimization to reduce
stop-and-go traffic.
Median Cost
(2006 dollars
per ton)
$2,200
$8,700
$12,300
$14,600
$18,800
$20,800
$23,500
Cost Range
(2006 dollars per ton)
$2,100
$1,400
$6,100
$2,700
$12,900
$4,700
$7,000
$6,800
$18,700
$104,200
$38,900
$46,700
$37,000
$149,900
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APPENDIX
Table 4. Continued
Employer Trip Reduction
Transit - Conventional
Service Upgrades
Park & Ride Lots
Modal Subsidies &
Vouchers
Transit - New Fixed
Guideway and Equipment
Bicycle and Pedestrian
Programs
Transit - Shuttles, Feeders,
and Paratransit
Alternative Fuel Transit
Vehicles and Facilities
Individual programs can vary widely. Can be voluntary or
mandatory for employers but usually voluntary for employees.
Employers offer workplace, work schedule, transportation and
parking options along with incentives and disincentives for
employee participation
Consists largely of improved frequency of fixed-route bus service.
Capital costs for construction of parking lots to support rideshare,
express bus, HOV lanes
Temporary subsidies to support new transit, carpool, or vanpool
programs
Mostly fixed transit-ways and commuter rail capital investments.
High initial capital costs, mediated by long service lives and
projected long-term increases in ridership can produce favorable
cost-effectiveness.
Construction of new bicycle or pedestrian facilities, improved access
to transit and activity centers, and education and safety program.
Usually this is service and/or facilities to supplement regular public
transportation routes. Shuttles and feeders are generally focused on
specific corridors with identified demand for transit access.
Paratransit serves wider areas with less demand - usually reflected in
higher costs and lower impacts
Predominately CNG replacement buses and shuttles
$26,600
$28,800
$50,300
$54,600
$77,700
$98,500
$102,400
$148,000
$6,800
$4,400
$10,100
$900
$10,000
$4,900
$14,400
$7,800
$205,500
$140,600
$82,800
$551,400
$551,200
$403,600
$2,311,000
$665,800
Source: (1) Transportation Research Board. The Congestion Mitigation and Air Quality Improvement Program: Assessing Ten Years of Experience. Special
Report 264. Washington, D.C.: 2002. In calculating cost-effectiveness, TRB assumed a weighting scheme of 1:4 for VOC:NOx. EPA has adjusted the TRB's
calculations for inflation according to the consumer price index established by the Bureau of Labor Statistics, U.S. Department of Labor.
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