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2 May 2008


[Federal Register: May 2, 2008 (Volume 73, Number 86)]
[Proposed Rules]               
[Page 24351-24487]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr02my08-28]                         
 

[[Page 24351]]

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Part II





Department of Transportation





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 National Highway Traffic Safety Administration



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49 CFR Parts 523, 531, 533, 534, 536 and 537



Average Fuel Economy Standards, Passenger Cars and Light Trucks; Model 
Years 2011-2015; Proposed Rule


[[Page 24352]]


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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Parts 523, 531, 533, 534, 536 and 537

[Docket No. NHTSA-2008-0089]
RIN 2127-AK29

 
Average Fuel Economy Standards, Passenger Cars and Light Trucks; 
Model Years 2011-2015

AGENCY: National Highway Traffic Safety Administration (NHTSA), 
Department of Transportation (DOT).

ACTION: Notice of Proposed Rulemaking (NPRM).

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SUMMARY: This document proposes substantial increases in the Corporate 
Average Fuel Economy (CAFE) standards for passenger cars and light 
trucks that would enhance energy security by improving fuel economy. 
Since the carbon dioxide (CO2) emitted from the tailpipes of 
new motor vehicles is the natural by-product of the combustion of fuel, 
the increased standards would also address climate change by reducing 
tailpipe emissions of CO2. Those emissions represent 97 
percent of the total greenhouse gas emissions from motor vehicles. 
Implementation of the new standards would dramatically add to the 
billions of barrels of fuel already saved since the beginning of the 
CAFE program in 1975.

DATES: Comments must be received on or before July 1, 2008.

ADDRESSES: You may submit comments to the docket number identified in 
the heading of this document by any of the following methods:
     Federal eRulemaking Portal: Go to http://
www.regulations.gov. Follow the online instructions for submitting 
comments.
     Mail: Docket Management Facility, M-30, U.S. Department of 
Transportation, West Building, Ground Floor, Rm. W12-140, 1200 New 
Jersey Avenue, SE., Washington, DC 20590.
     Hand Delivery or Courier: West Building Ground Floor, Room 
W12-140, 1200 New Jersey Avenue, SE., between 9 a.m. and 5 p.m. Eastern 
Time, Monday through Friday, except Federal holidays.
     Fax: (202) 493-2251.
    Regardless of how you submit your comments, you should mention the 
docket number of this document.
    You may call the Docket Management Facility at 202-366-9826.
    Instructions: For detailed instructions on submitting comments and 
additional information on the rulemaking process, see the Public 
Participation heading of the Supplementary Information section of this 
document. Note that all comments received will be posted without change 
to http://www.regulations.gov, including any personal information 
provided.
    Privacy Act: Please see the Privacy Act heading under Rulemaking 
Analyses and Notices.

FOR FURTHER INFORMATION CONTACT: For policy and technical issues: Ms. 
Julie Abraham or Mr. Peter Feather, Office of Rulemaking, National 
Highway Traffic Safety Administration, 1200 New Jersey Avenue, SE., 
Washington, DC 20590. Telephone: Ms. Abraham (202) 366-1455; Mr. 
Feather (202) 366-0846.
    For legal issues: Mr. Stephen Wood or Ms. Rebecca Schade, Office of 
the Chief Counsel, National Highway Traffic Safety Administration, 1200 
New Jersey Avenue, SE., Washington, DC 20590. Telephone: (202) 366-
2992.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Executive overview
    A. Summary
    B. Energy Independence and Security Act of 2007
    C. Proposal
    1. Standards
    a. Stringency
    b. Benefits
    c. Costs
    d. Flexibilities
    2. Credits
II. Background
    A. Contribution of fuel economy improvements to addressing 
energy independence and security and climate change
    1. Relationship between fuel economy and CO2 tailpipe 
emissions
    2. Fuel economy improvements/CO2 tailpipe emission 
reductions since 1975
    B. Chronology of events since the National Academy of Sciences 
called for reforming and increasing CAFE standards
    1. National Academy of Sciences CAFE report (February 2002)
    a. Significantly increasing CAFE standards without reforming 
them would adversely affect safety
    b. Environmental and other externalities justify increasing the 
CAFE standards
    2. Final rule establishing reformed (attribute-based) CAFE 
standards for MY 2008-2011 light trucks (March 2006)
    3. Twenty-in-Ten Initiative (January 2007)
    4. Request for passenger car and light truck product plans 
(February 2007)
    5. Supreme Court decision in Massachusetts v. EPA (April 2007)
    6. Coordination between NHTSA and EPA on development of 
rulemaking proposals (Summer-Fall 2007)
    7. Ninth Circuit decision re final rule for MY 2008-2011 light 
trucks (November 2007)
    8. Enactment of Energy Independence and Security Act of 2007 
(December 2007)
    C. Energy Policy and Conservation Act, as amended
    1. Vehicles subject to standards for automobiles
    2. Mandate to set standards for automobiles
    3. Structure of standards
    4. Factors governing or considered in the setting of standards
    5. Consultation in setting standards
    6. Compliance flexibility and enforcement
III. Fuel economy enhancing technologies
    A. Data sources for technology assumptions
    B. Technologies and estimates of costs and effectiveness
    1. Engine technologies
    2. Transmission technologies
    3. Vehicle technologies
    4. Accessory technologies
    5. Hybrid technologies
    C. Technology synergies
    D. Technology cost learning curve
    E. Ensuring sufficient lead time
    1. Linking to redesign and refresh
    2. Technology phase-in caps
IV. Basis for attribute-based structure for setting fuel economy 
standards
    A. Why attribute-based instead of a single industry-wide 
average?
    B. Which attribute is most appropriate?
    1. Footprint-based function
    2. Functions based on other attributes
    C. The continuous function
V. Volpe model/analysis/generic description of function
    A. The Volpe model
    1. What is the Volpe model?
    2. How does the Volpe model apply technologies to manufacturers' 
future fleets?
    3. What effects does the Volpe model estimate?
    4. How can the Volpe model be used to calibrate and evaluate 
potential CAFE standards?
    5. How has the Volpe model been updated since the April 2006 
light truck CAFE final rule?
    a. Technology synergies
    b. Technology learning curves
    c. Calibration of reformed CAFE standards
    6. What manufacturer information does the Volpe model use?
    7. What economic information does the Volpe model use?
    a. Costs of fuel economy technologies
    b. Potential opportunity costs of improved fuel economy
    c. The on-road fuel economy `gap'
    d. Fuel prices and the value of saving fuel
    e. Consumer valuation of fuel economy and payback period
    f. Vehicle survival and use assumptions
    g. Growth in total vehicle use
    h. Accounting for the rebound effect of higher fuel economy
    i. Benefits from increased vehicle use
    j. Added costs from congestion, crashes and noise
    k. Petroleum consumption and import externalities
    l. Air pollutant emissions
    (i) Impacts on criteria air pollutant emissions
    (ii) Reductions in CO2 emissions
    (iii) Economic value of reductions in CO2 emissions

[[Page 24353]]

    m. The value of increased driving range
    n. Discounting future benefits and costs
    o. Accounting for uncertainty in benefits and costs
    B. How has NHTSA used the Volpe model to select the proposed 
standards?
    1. Establishing a continuous function standard
    2. Calibration of initial continuous function standards
    3. Adjustments to address policy considerations
    a. Curve crossings
    b. Steep curve for passenger cars
    c. Risk of upsizing
VI. Proposed fuel economy standards
    A. Standards for passenger cars and light trucks
    1. Proposed passenger car standards MY 2011-2015
    2. Proposed light truck standards MY 2011-2015
    3. Energy and environmental backstop
    4. Combined fleet performance
    B. Estimated technology utilization under proposed standards
    C. Costs and benefits of proposed standards
    D. Flexibility mechanisms
    E. Consistency of proposed standards with EPCA statutory factors
    1. Technological feasibility
    2. Economic practicability
    3. Effect of other motor vehicle standards of the Government on 
fuel economy
    4. Need of the U.S. to conserve energy
    F. Other considerations in setting standards under EPCA
    1. Safety
    2. Alternative fuel vehicle incentives
    3. Manufacturer credits
    G. Environmental impacts of the proposed standards
    H. Balancing the factors to determine maximum feasible CAFE 
levels
VII. Standards for commercial medium- and heavy-duty on-highway 
vehicles and ``work trucks''
VIII. Vehicle classification
    A. Origins of the regulatory definitions
    B. Rationale for the regulatory definitions in light of the 
current automobile market
    C. NHTSA is not proposing to change regulatory definitions at 
this time
IX. Enforcement
    A. Overview
    B. CAFE credits
    1. Credit trading
    2. Credit transferring
    3. Credit carry-forward/carry-back
    C. Extension and phasing out of flexible-fuel incentive program
X. Regulatory alternatives
XI. Sensitivity and Monte Carlo analysis
XII. Public participation
XIII. Regulatory notices and analyses
    A. Executive Order 12866 and DOT Regulatory Policies and 
Procedures
    B. National Environmental Policy Act
    C. Regulatory Flexibility Act
    D. Executive Order 13132 (Federalism)
    E. Executive Order 12988 (Civil Justice Reform)
    F. Unfunded Mandates Reform Act
    G. Paperwork Reduction Act
    H. Regulation Identifier Number (RIN)
    I. Executive Order 13045
    J. National Technology Transfer and Advancement Act
    K. Executive Order 13211
    L. Department of Energy Review
    M. Plain Language
    N. Privacy Act
XIV. Regulatory Text

I. Executive overview

A. Summary

    This document is being issued pursuant to the Energy Independence 
and Security Act of 2007 (EISA), which Congress passed in December 
2007. EISA mandates the setting of separate maximum feasible standards 
for passenger cars and for light trucks at levels sufficient to ensure 
that the average fuel economy of the combined fleet of all passenger 
cars and light trucks sold by all manufacturers in the U.S. in model 
year (MY) 2020 equals or exceeds 35 miles per gallon. That is a 40 
percent increase above the average of approximately 25 miles per gallon 
for the current combined fleet.
    Congress enabled NHTSA to require these substantial increases in 
fuel economy by requiring that passenger car standards be reformed 
through basing them on one or more vehicle attributes. The attribute-
based approach was originally recommended by the National Academy of 
Sciences in 2002 and adopted by NHTSA for light trucks in 2006. The new 
approach is a substantial improvement over the old approach of 
specifying the same numerical standard for each manufacturer. It avoids 
creating undue risks of adverse safety and employment impacts and 
distributes compliance responsibilities among the vehicle manufacturers 
more equitably.
    This document proposes standards for MYs 2011-2015, the maximum 
number of model years for which NHTSA can establish standards in a 
single rulemaking under EISA. Since lead time is a significant 
consideration in determining the stringency of future standards, the 
agency needs to establish the standards as far in advance as possible 
so as to maximize the amount of lead time for manufacturers to develop 
and implement plans for making the vehicle design changes necessary to 
achieve the requirements of EISA.
    In developing the proposed standards, the agency considered the 
four statutory factors underlying maximum feasibility (technological 
feasibility, economic practicability, the effect of other standards of 
the Government on fuel economy, and the need of the nation to conserve 
energy) as well as other relevant considerations such as safety. After 
assessing what fuel saving technologies would be available, how 
effective they are, and how quickly they could be introduced, and then 
factoring that information into the computer model its uses for 
applying technologies to particular vehicle models, the agency then 
balanced the factors relevant to standard setting. In its decision 
making, the agency used a marginal benefit-cost analysis that placed 
monetary values on relevant externalities (both energy security and 
environmental externalities, including the benefits of reductions in 
CO2 emissions). In the above process, the agency consulted 
with the Department of Energy and particularly the Environmental 
Protection Agency regarding a wide variety of matters, including, for 
example, the cost and effectiveness of available technologies, 
improvements to the computer model, and the selection of appropriate 
analytical assumptions.
    This document also proposes to add a new regulation designed to 
give manufacturers added flexibility in using credits earned by 
exceeding CAFE standards. The regulation would authorize the trading of 
credits between manufacturers. In addition, it would permit a 
manufacturer to transfer its credits from one of its compliance 
categories to another of its categories.
    NHTSA is also publishing two companion documents, one requesting 
vehicle manufacturers to provide up-to-date product plans for the model 
years covered by this document, and the other inviting Federal, State, 
and local agencies, Indian tribes, and the public to participate in 
identifying the environmental issues and reasonable alternatives to be 
examined in an environmental impact statement.

B. Energy Independence and Security Act of 2007

    The Energy Independence and Security Act of 2007 (EISA)\1\ builds 
on the President's ``Twenty in Ten'' initiative, which was announced in 
January 2007. That initiative sought to reduce gasoline usage by 20 
percent in the next 10 years. The enactment of EISA represents a major 
step forward in expanding the production of renewable fuels, reducing 
oil consumption, and confronting global climate change.
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    \1\ Pub. L. 110-140, 121 Stat. 1492 (Dec. 18, 2007).
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    EISA will help reduce America's dependence on oil by reducing U.S. 
demand for oil by setting a national fuel economy standard of at least 
35 miles per gallon by 2020--which will increase fuel economy standards 
by 40 percent and save billions of gallons of fuel. In January 2007, 
the President called for the first statutory increase in fuel economy 
standards for passenger

[[Page 24354]]

automobiles (referred to below as ``passenger cars'') since those 
standards were mandated in 1975, and EISA delivers on that request. 
EISA also includes an important reform the President has called for 
that allows the Transportation Department to issue ``attribute-based 
standards,'' which will ensure that increased fuel efficiency does not 
come at the expense of automotive safety. EISA also mandates increases 
in the use of renewable fuels by setting a mandatory Renewable Fuel 
Standard requiring fuel producers to use at least 36 billion gallons of 
renewable fuels in 2022.
    As the President noted in signing EISA, the combined effect of the 
various actions required by the Act will be to produce some of the 
largest CO2 emission reductions in our nation's history.
    EISA made a number of important changes to the Energy Policy and 
Conservation Act (EPCA) (Pub. L. 94-163), the 1975 statute that governs 
the CAFE program. EISA:
     Replaces the old statutory default standard of 27.5 mpg 
for passenger cars with a mandate to establish separate passenger car 
and light truck standards annually, beginning with MY 2011, set at the 
maximum feasible level. The standards for MYs 2011-2020 must, as a 
minimum, be set sufficiently high to ensure that the average fuel 
economy of the combined industrywide fleet of all new passenger cars 
and light trucks sold in the United States during MY 2020 is at least 
35 mpg.\2\
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    \2\ Although NHTSA established an attribute-based standard for 
MY 2011 light trucks in its 2006 final rule, EISA mandates a new 
rulemaking, reflecting new statutory considerations and a new, up-
to-date administrative record, and consistent with EPCA as amended 
by EISA, to establish the standard for those light trucks.
---------------------------------------------------------------------------

     Limits to five the number of years for which standards can 
be established in a single rulemaking. That requirement, in combination 
with the requirement to start rulemaking with MY 2011, necessitates 
limiting this rulemaking to MYs 2011-2015.
     Mandates the reforming of CAFE standards for passenger 
cars by requiring that all CAFE standards be based on one or more 
vehicle attributes, thus ensuring that the improvements in fuel economy 
do not come at the expense of safety. NHTSA pioneered that approach in 
its last rulemaking on CAFE standards for light trucks.
     Requires that for each model year, beginning with MY 2011, 
the domestic passenger cars of each manufacturer of those cars must 
achieve a measured average fuel economy that is not less than 92 
percent of the average fuel economy of the combined fleet of domestic 
and non-domestic passenger cars sold in the United States in that model 
year.
     Provides greater flexibility for automobile manufacturers 
by (a) increasing from three to five the number of years that a 
manufacturer can carry forward the compliance credits it earns for 
exceeding CAFE standards, (b) allowing a manufacturer to transfer the 
credits it has earned from one of its classes of automobiles to 
another, and (c) authorizing the trading of credits between 
manufacturers.

C. Proposal

1. Standards
a. Stringency
    This document proposes to set attribute-based fuel economy 
standards for passenger cars and light trucks consistent with the 
Reformed CAFE approach that NHTSA used in establishing the light truck 
standards for MY 2008-2011 light trucks. Separate passenger car 
standards would be set for MYs 2011-2015, and light truck standards 
would be set for MYs 2011-2015. As noted above, EISA limits the number 
of model years for which standards may be established in a single 
rulemaking to five. We are proposing to establish standards for five 
years to maximize the amount of lead time that we can provide the 
manufacturers. This is necessary to make it possible to achieve the 
levels of average fuel economy required by MY 2020.
    Each vehicle manufacturer's required level of CAFE would be based 
on target levels of average fuel economy set for vehicles of different 
sizes and on the distribution of that manufacturer's vehicles among 
those sizes. Size would be defined by vehicle footprint. The level of 
the performance target for each footprint would reflect the 
technological and economic capabilities of the industry. The target for 
each footprint would be the same for all manufacturers, regardless of 
differences in their overall fleet mix. Compliance would be determined 
by comparing a manufacturer's harmonically averaged fleet fuel economy 
levels in a model year with a required fuel economy level calculated 
using the manufacturer's actual production levels and the targets for 
each footprint of the vehicles that it produces.
    The proposed standards were developed using a computer model (known 
as the ``Volpe Model'') that, for any given model year, applies 
technologies to a manufacturer's fleet until the manufacturer reaches 
compliance with the standard under consideration. The standards were 
tentatively set at levels such that, considering the seven largest 
manufacturers, the cost of the last technology application equaled the 
benefits of the improvement in fuel economy resulting from that 
application. We reviewed these proposed standards to consider the 
underlying increased use of technologies and the associated impact on 
the industry. This process recognizes that the relevance of costs in 
achieving benefits, and uses benefit figures that include the value of 
reducing the negative externalities (economic and environmental) from 
producing and consuming fuel. These environmental externalities 
include, among other things, reducing tailpipe emissions of CO2.\3\ In 
view of the process used to develop the proposed standards, they are 
also referred to as ``optimized standards.''
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    \3\ The externalities included in our analysis do not, however, 
include those associated with the reduction of the other GHG emitted 
by automobiles, i.e., methane (CH4), nitrous oxide (N2O), and 
hydroflurocarbons (HFCs). Actual air conditioner operation is not 
included in the test procedures used to obtain both (1) emission 
rates for purposes of determining compliance with EPA criteria 
pollutant emission standards and (2) fuel economy values for 
purposes of determining compliance with NHTSA CAFE standards, 
although air conditioner operation is included in ``supplemental'' 
federal test procedures used to determine compliance with 
corresponding and separate EPA criteria pollutant emission 
standards.
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    Compared to the 2006 rulemaking that established the MY 2008-11 
CAFE standards for light trucks, this rulemaking much more fully 
captures the value of the costs and benefits of setting CAFE standards. 
This is important because assumptions regarding gasoline price 
projections, along with assumptions for externalities, are based on 
changed economic and environmental and energy security conditions and 
play a big role in the agency's balancing of the statutory 
considerations in arriving at a determination of maximum feasible. In 
light of EISA and the need to balance the statutory considerations in a 
way that reflects the current need of the nation to conserve energy, 
including the current assessment of the climate change problem, the 
agency revisited the various assumptions used in the Volpe Model to 
determine the level of the standards. Specifically, in running the 
Volpe Model and stopping at a point where marginal costs equaled 
marginal benefits or where net benefits to society are maximized, the 
agency used higher gasoline prices and higher estimates for energy 
security values ($0.29 per gallon instead of $0.09 per gallon). The 
agency also monetized carbon dioxide (at

[[Page 24355]]

$7.00/ton), which it did not do in the previous rulemaking, and 
expanded its technology list. In addition, the agency used cost 
estimates that reflect economies of scale and estimated ``learning''-
driven reductions in the cost of technologies as well as quicker 
penetration rates for advanced technologies. These changes to the 
inputs to the model had a major impact on increasing the benefits in 
certain model years by allowing for greater penetration of 
technologies.
    The agency cannot set out the exact level of CAFE that each 
manufacturer will be required to meet for each model year under the 
proposed passenger car or light truck standards since the levels will 
depend on information that will not be available until the end of each 
of the model years, i.e., the final actual production figures for each 
of those years. The agency can, however, project what the industry wide 
level of average fuel economy would be for passenger cars and for light 
trucks if each manufacturer produced its expected mix of automobiles 
and just met its obligations under the proposed ``optimized'' standards 
for each model year. Adjacent to each average fuel economy figure is 
the estimated associated level of tailpipe emissions of CO2 that would 
be achieved.\4\
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    \4\ Given the contributions made by CAFE standards to addressing 
not only energy independence and security, but also to reducing 
tailpipe emissions of CO2, fleet performance is stated in the above 
discussion both in terms of fuel economy and the associated 
reductions in tailpipe emissions of CO2 since the CAFE standard will 
have the practical effect of limiting those emissions approximately 
to the indicated levels during the official CAFE test procedures 
established by EPA. The relationship between fuel consumption and 
carbon dioxide emissions is discussed ubiquitously, such as at 
www.fueleconomy.gov, a fuel economy-related Web site managed by DOE 
and EPA (see http://www.fueleconomy.gov/feg/contentIncludes/co2_
inc.htm, which provides a rounded value of 20 pounds of CO2 per 
gallon of gasoline). (Last accessed April 20, 2008.) The CO2 
emission rates shown are based on gasoline characteristics. Because 
diesel fuel contains more carbon (per gallon) than gasoline, the 
presence of diesel engines in the fleet--which NHTSA expects to 
increase in response to the proposed CAFE standards--will cause the 
actual CO2 emission rate corresponding to any given CAFE level to be 
slightly higher than shown here. (The agency projects that 4 percent 
of the MY 2015 passenger car fleet and 10 percent of the MY 2015 
light truck fleet will have diesel engines.) Conversely (and 
hypothetically), applying the same CO2 emission standard to both 
gasoline and diesel vehicles would discourage manufacturers from 
improving diesel engines, which show considerable promise as a means 
to improve fuel economy.

    For passenger cars:
MY 2011: 31.2 mpg (285 g/mi of tailpipe emissions of CO2)
MY 2012: 32.8 mpg (271 g/mi of tailpipe emissions of CO2)
MY 2013: 34.0 mpg (261 g/mi of tailpipe emissions of CO2)
MY 2014: 34.8 mpg (255 g/mi of tailpipe emissions of CO2)
MY 2015: 35.7 mpg (249 g/mi of tailpipe emissions of CO2)

    For light trucks:

MY 2011: 25.0 mpg (355 g/mi of tailpipe emissions of CO2)
MY 2012: 26.4 mpg (337 g/mi of tailpipe emissions of CO2)
MY 2013: 27.8 mpg (320 g/mi of tailpipe emissions of CO2)
MY 2014: 28.2 mpg (315 g/mi of tailpipe emissions of CO2)
MY 2015: 28.6 mpg (310 g/mi of tailpipe emissions of CO2)

    The combined industry wide average fuel economy (in miles per 
gallon, or mpg) levels (in grams per mile, or g/mi) for both cars and 
light trucks, if each manufacturer just met its obligations under the 
proposed ``optimized'' standards for each model year, would be as 
follows:

MY 2011: 27.8 mpg (2.5 mpg increase above MY 2010; 320 g/mi CO2)
MY 2012: 29.2 mpg (1.4 mpg increase above MY 2011; 304 g/mi CO2)
MY 2013: 30.5 mpg (1.3 mpg increase above MY 2012; 291 g/mi CO2)
MY 2014: 31.0 mpg (0.5 mpg increase above MY 2013; 287 g/mi CO2)
MY 2015: 31.6 mpg (0.6 mpg increase above MY 2014; 281 g/mi CO2)

    The annual average increase during this five year period is 
approximately 4.5 percent. Due to the uneven distribution of new model 
introductions during this period and to the fact that significant 
technological changes can be most readily made in conjunction with 
those introductions, the annual percentage increases are greater in the 
early years in this period.
    Given a starting point of 31.8 mpg in MY 2015, the average annual 
increase for MYs 2016-2020 would need to be only 2.1 percent in order 
for the projected combined industry wide average to reach at least 35 
mpg by MY 2020, as mandated by EISA.
    In addition, per EISA, each manufacturer's domestic passenger fleet 
is required in each model year to achieve 27.5 mpg or 92 percent of the 
CAFE of the industry wide combined fleet of domestic and non-domestic 
passenger cars \5\ for that model year, whichever is higher. This 
requirement results in the following alternative minimum standard (not 
attribute-based) for domestic passenger cars:
---------------------------------------------------------------------------

    \5\ Those numbers set out several paragraphs above.

MY 2011: 28.7 mpg (310 g/mi of tailpipe emissions of CO2)
MY 2012: 30.2 mpg (294 g/mi of tailpipe emissions of CO2)
MY 2013: 31.3 mpg (284 g/mi of tailpipe emissions of CO2)
MY 2014: 32.0 mpg (278 g/mi of tailpipe emissions of CO2)
MY 2015: 32.9 mpg (270 g/mi of tailpipe emissions of CO2)

    The agency is also issuing, along with this document, a notice 
requesting updated product plan information and other data to assist in 
developing a final rule. We recognize that the manufacturer product 
plans relied upon in developing this proposal--those plans received in 
late spring of 2007 in response to an early 2007 request for 
information--may already be outdated in some respects. We fully expect 
that manufacturers have revised those plans to reflect subsequent 
developments, especially the enactment of EISA.
    We solicit comment on all aspects of this proposal, including the 
methodology, economic assumptions, analysis and tentative conclusions. 
In particular, we solicit comment on whether the proposed levels of 
CAFE satisfy EPCA, e.g., reflect an appropriate balancing of the 
explicit statutory factors and other relevant factors. Other specific 
areas where we request comments are identified elsewhere in this 
preamble and in the Preliminary Regulatory Impact Analysis (PRIA). 
Based on public comments and other information, including new data and 
analysis, and updated product plans,\6\ the standards adopted in the 
final rule could well be different from those proposed in this 
document.
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    \6\ The proposed standards are, in the first instance, based on 
the confidential product plans submitted by the manufacturers in the 
spring of 2006. The final rule will be based on the confidential 
plans submitted in the next several months. The agency anticipates 
that those new plans, which presumably will reflect in some measure 
the enactment of EISA and the issuance of this proposal, will 
project higher levels of average fuel economy than the 2006 product 
plans.
---------------------------------------------------------------------------

b. Benefits
    We estimate that the proposed standards for passenger cars would 
save approximately 18.7 billion gallons of fuel and avoid tailpipe 
CO2 emissions by 178 billion metric tons over the lifetime 
of the passenger cars sold during those model years, compared to the 
fuel savings and emissions reductions that would occur if the standards 
remained at the adjusted baseline (i.e., the higher of manufacturer's 
plans and the manufacturer's required level of average fuel economy for 
MY 2010).
    We estimate that the value of the total benefits of the proposed 
passenger car standards would be approximately $31 billion \7\ over the 
lifetime of the 5 model

[[Page 24356]]

years combined. This estimate of societal benefits includes direct 
impacts from lower fuel consumption as well as externalities and also 
reflects offsetting societal costs resulting from the rebound effect.
---------------------------------------------------------------------------

    \7\ The $22 billion estimate is based on a 7% discount rate for 
valuing future impacts. NHTSA estimated benefits using both 7% and 
3% discount rates. Under a 3% rate, net consumer benefits for 
passenger car CAFE improvements total $28 million.
---------------------------------------------------------------------------

    We estimate that the proposed standards for light trucks would save 
approximately 36 billion gallons of fuel and prevent the tailpipe 
emission of 343 million metric tons of CO2 over the lifetime 
of the light trucks sold during those model years, compared to the fuel 
savings and emissions reductions that would occur if the standards 
remained at the adjusted baseline. We estimate that the value of the 
total benefits of the proposed light truck standards would be 
approximately $57 billion \8\ over the lifetime of the 5 model years of 
light trucks combined. This estimate of societal benefits includes 
direct impacts from lower fuel consumption as well as externalities and 
also reflects offsetting societal costs resulting from the rebound 
effect.
---------------------------------------------------------------------------

    \8\ The $56 billion estimate is based on a 7% discount rate for 
valuing future impacts. NHTSA estimated benefits using both 7% and 
3% discount rates. Under a 3% rate, net consumer benefits for light 
truck CAFE improvements total $70 million.
---------------------------------------------------------------------------

c. Costs
    The total costs for manufacturers just complying with the standards 
for MY 2011-2015 passenger cars would be approximately $16 billion, 
compared to the costs they would incur if the standards remained at the 
adjusted baseline. The resulting vehicle price increases to buyers of 
MY 2015 passenger cars would be recovered or paid back \9\ in 
additional fuel savings in an average of 56 months, assuming fuel 
prices ranging from $2.26 per gallon in 2016 to $2.51 per gallon in 
2030.\10\
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    \9\ See Section V.A.7 below for discussion of payback period.
    \10\ The fuel prices (shown here in 2006 dollars) used to 
calculate the length of the payback period are those projected 
(Annual Energy Outlook 2008, revised early release) by the Energy 
Information Administration over the life of the MY 2011-2015 light 
trucks, not current fuel prices.
---------------------------------------------------------------------------

    The total costs for manufacturers just complying with the standards 
for MY 2011-2015 light trucks would be approximately $31 billion, 
compared to the costs they would incur if the standards remained at the 
adjusted baseline. The resulting vehicle price increases to buyers of 
MY 2015 light trucks would be paid back in additional fuel savings in 
an average of 50 months, assuming fuel prices ranging from $2.26 to 
$2.51 per gallon.
d. Flexibilities
    The agency's benefit and cost estimates do not reflect the 
availability and use of flexibility mechanisms, such as compliance 
credits and credit trading because EPCA prohibits NHTSA from 
considering the effects of those mechanisms in setting CAFE standards. 
EPCA has precluded consideration of the FFV adjustments ever since it 
was amended to provide for those adjustments. The prohibition against 
considering compliance credits was added by EISA.
    The benefit and compliance cost estimates used by the agency in 
determining the maximum feasible level of the CAFE standards assume 
that manufacturers will rely solely on the installation of fuel economy 
technology to achieve compliance with the proposed standards. In 
reality, however, manufacturers are likely to rely to some extent on 
flexibility mechanisms provided by EPCA (as described in Section VI) 
and will thereby reduce the cost of complying with the proposed 
standards to a meaningful extent.
2. Credits
    NHTSA is also proposing a new Part 536 on use of ``credits'' earned 
for exceeding applicable CAFE standards. Part 536 will implement the 
provisions in EISA authorizing NHTSA to establish by regulation a 
credit trading program and directing it to establish by regulation a 
credit transfer program.\11\ Since its enactment, EPCA has permitted 
manufacturers to earn credits for exceeding the standards and to apply 
those credits to compliance obligations in years other than the model 
year in which it was earned. EISA extended the ``carry-forward'' period 
to five model years, and left the ``carry-back'' period at three model 
years. Under the proposed Part 536, credit holders (including, but not 
limited to, manufacturers) will have credit accounts with NHTSA, and 
will be able to hold credits, apply them to compliance with CAFE 
standards, transfer them to another ``compliance category'' for 
application to compliance there, or trade them. A credit may also be 
cancelled before its expiry date, if the credit holder so chooses. 
Traded credits will be subject to an ``adjustment factor'' to ensure 
total oil savings are preserved, as required by EISA. EISA also 
prohibits credits earned before MY 2011 from being transferred, so 
NHTSA has developed several regulatory restrictions on trading and 
transferring to facilitate Congress' intent in this regard. Additional 
information on the proposed Part 536 is available in section IX below.
---------------------------------------------------------------------------

    \11\ Congress required that DOT establish a credit 
``transferring'' regulation, to allow individual manufacturers to 
move credits from one of their fleets to another (e.g., using a 
credit earned for exceeding the light truck standard for compliance 
in the domestic passenger car standard). Congress allowed DOT to 
establish a credit ``trading'' regulation, so that credits may be 
bought and sold between manufacturers and other parties.
---------------------------------------------------------------------------

II. Background

A. Contribution of Fuel Economy Improvements to Addressing Energy 
Independence and Security and Climate Change

1. Relationship Between Fuel Economy and CO2 Tailpipe Emissions
    Improving fuel economy reduces the amount of tailpipe emissions of 
CO2. CO2 emissions are directly linked to fuel consumption because CO2 
is the ultimate end product of burning gasoline. The more fuel a 
vehicle burns, the more CO2 it emits. Since the CO2 emissions are 
essentially constant per gallon of fuel combusted, the amount of fuel 
consumption per mile is directly related to the amount of CO2 emissions 
per mile. Thus, requiring improvements in fuel economy indirectly, but 
necessarily requires reductions in tailpipe emissions of CO2 emissions. 
This can be seen in the table below. To take the first value of fuel 
economy from the table below as an example, a standard of 21.0 mpg 
would indirectly place substantially the same limit on tailpipe CO2 
emissions as a tailpipe CO2 emission standard of 423.2 g/mi of CO2, and 
vice versa.\12\
---------------------------------------------------------------------------

    \12\ To the extent that manufacturers comply with a CAFE 
standard with diesel automobiles instead of gasoline ones, the level 
of CO2 tailpipe emissions would be less. As noted above, the agency 
projects that 4 percent of the MY 2015 passenger car fleet and 10 
percent of the MY 2015 light truck fleet will have diesel engines. 
The CO2 tailpipe emissions of a diesel powered passenger car are 15 
percent higher than those of a comparable gasoline power passenger 
car.

[[Page 24357]]



                       Table II-1.--CAFE Standards (mpg) and the Limits They Indirectly Place on Tailpipe Emissions of CO2 (g/mi)*
--------------------------------------------------------------------------------------------------------------------------------------------------------
                  CAFE Std                     CO2     CAFE Std    CO2     CAFE Std    CO2     CAFE Std    CO2     CAFE Std    CO2     CAFE Std    CO2
--------------------------------------------------------------------------------------------------------------------------------------------------------
21.0.......................................    444.4       26.0    341.8       31.0    286.7       36.0    246.9       41.0    216.8       46.0    193.2
22.0.......................................    404.0       27.0    329.1       32.0    277.7       37.0    240.2       42.0    211.6       47.0    188.3
23.0.......................................    386.4       28.0    317.4       33.0    269.3       38.0    233.9       43.0    206.7       48.0    189.1
24.0.......................................    370.3       29.0    306.4       34.0    261.4       39.0    227.9       44.0    202.0       49.0    181.4
25.0.......................................    355.5       30.0    296.2       35.0    253.9       40.0    222.2       45.0    197.5       50.0   177.7
--------------------------------------------------------------------------------------------------------------------------------------------------------
 This table is based on calculations that use the figure of 8,887 grams of CO2 per gallon of gasoline consumed, based on characteristics of gasoline
  vehicle certification fuel. To convert a mpg value into CO2 g/mi, divide 8,887 by the mpg value.

2. Fuel Economy Improvements/CO2 Tailpipe Emission 
Reductions Since 1975
    The need to take action to reduce greenhouse gas emissions, e.g., 
motor vehicle tailpipe emissions of CO2, in order to forestall and even 
mitigate climate change is well recognized.\13\ Less well recognized 
are two related facts. First, improving fuel economy is the only method 
available to motor vehicle manufacturers for making significant 
reductions in the CO2 tailpipe emissions of motor vehicles and thus 
must be the core element of any effort to achieve those reductions. 
Second, the significant improvements in fuel economy since 1975, due to 
the CAFE standards and in some measure to market conditions as well, 
have directly caused reductions in the rate of CO2 tailpipe emissions 
per vehicle.
---------------------------------------------------------------------------

    \13\ IPCC (2007): Climate Change 2007: Mitigation of Climate 
Change. Contribution of Working Group III to the Fourth Assessment 
Report of the Intergovernmental Panel on Climate Change [B. Metz, O. 
Davidson, P. Bosch, R. Dave, and L. Meyer (eds.)]. Cambridge 
University Press, Cambridge, United Kingdom and New York, NY, USA.
---------------------------------------------------------------------------

    In 1975, passenger cars manufactured for sale in the U.S. averaged 
only 15.8 mpg (562.5 grams of CO2 per mile or 562.5 g/mi of CO2). By 
2007, the average fuel economy of passenger cars had increased to 31.3 
mpg, causing g/mi of CO2 to fall to 283.9. Similarly, in 1975, light 
trucks averaged 13.7 mpg (648.7 g/mi of CO2). By 2007, the average fuel 
economy of light trucks had risen to 23.1 mpg, causing g/mi of CO2 to 
fall to 384.7.

  Table II-2.--Improvements in MPG/Reductions in G/MI of CO2 Passenger
                                  Cars
                               [1975-2007]
------------------------------------------------------------------------
                                                    MPG      G/MI of CO2
------------------------------------------------------------------------
1975..........................................         15.8        562.5
2007..........................................         31.3        283.9
------------------------------------------------------------------------


 Table II-3.--Improvements in MPG/Reductions in G/MI of CO2 Light Trucks
                               [1975-2007]
------------------------------------------------------------------------
                                                    MPG      G/MI of CO2
------------------------------------------------------------------------
1975..........................................         13.7        648.7
2007..........................................         23.1        384.7
------------------------------------------------------------------------

    If fuel economy had not increased above the 1975 level, cars and 
light trucks would have emitted an additional 11 billion metric tons of 
CO2 into the atmosphere between 1975 and 2005. That is nearly the 
equivalent of emissions from all U.S. fossil fuel combustion for two 
years (2004 and 2005). The figure below shows the amount of CO2 
emissions avoided due to increases in fuel economy.
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B. Chronology of Events Since the National Academy of Sciences Called 
for Reforming and Increasing CAFE Standards

1. National Academy of Sciences CAFE Report (February 2002)
a. Significantly Increasing CAFE Standards Without Reforming Them Would 
Adversely Affect Safety
    In the congressionally-mandated report entitled ``Effectiveness and 
Impact of Corporate Average Fuel Economy (CAFE) Standards,'' \14\ a 
committee of the National Academy of Sciences (NAS) (``2002 NAS 
Report'') concluded that the then-existing form of passenger car and 
light truck CAFE standards created an incentive for vehicle 
manufacturers to comply in part by downweighting and even downsizing 
their vehicles and that these actions had led to additional fatalities. 
The committee explained that these problems arose because the CAFE 
standards subjected all passenger cars to the same fuel economy target 
and all light trucks to the same target, regardless of their weight, 
size, or load-carrying capacity. The committee said that this 
experience suggests that consideration should be given to developing a 
new system of fuel economy targets that reflects differences in such 
vehicle attributes.
---------------------------------------------------------------------------

    \14\ National Research Council, ``Effectiveness and Impact of 
Corporate Average Fuel Economy (CAFE) Standards,'' National Academy 
Press, Washington, DC (2002). Available at http://www.nap.edu/
openbook.php?isbn=0309076013 (last accessed April 20, 2008). The 
conference committee report for the Department of Transportation and 
Related Agencies Appropriations Act for FY 2001 (Pub. L. 106-346) 
directed NHTSA to fund a study by NAS to evaluate the effectiveness 
and impacts of CAFE standards (H. Rep. No. 106-940, p. 117-118). In 
response to the direction from Congress, NAS published this lengthy 
report.
---------------------------------------------------------------------------

    Looking to the future, the committee said that while it is 
technically feasible and potentially economically practicable to 
improve fuel economy without reducing vehicle weight or size and, 
therefore, without significantly affecting the safety of motor vehicle 
travel, the actual strategies chosen by manufacturers to improve fuel 
economy will depend on a variety of factors. In the committee's 
judgment, the extensive downweighting and downsizing that occurred 
after fuel economy requirements were established in the 1970s suggested 
that the likelihood of a similar response to further increases in fuel 
economy requirements must be considered seriously. Any reduction in 
vehicle size and weight would have safety implications.
    The committee cautioned that the safety effects of downsizing and 
downweighting are likely to be hidden by the generally increasing 
safety of the light-duty vehicle fleet.\15\ It said that some might 
argue that this improving safety picture means that there is room to 
improve fuel economy without adverse safety consequences; however, such 
an approach would not achieve the goal of avoiding the adverse safety 
consequences of fuel economy increases. Rather, the safety penalty 
imposed by increased fuel economy (if weight reduction is one of the 
measures) will be more difficult to identify in light of the continuing 
improvement in traffic safety. Although it is anticipated that these 
safety innovations will improve the safety of vehicles of all sizes, 
that does not mean that downsizing to achieve fuel economy improvements 
will not have any safety costs. If two vehicles of the same size are 
modified, one both by downsizing it and adding the safety innovations 
and the other just by adding the safety innovations, the latter vehicle 
will in all likelihood be safer.
---------------------------------------------------------------------------

    \15\ Two of the 12 members of the committee dissented from the 
majority's safety analysis and conclusions.
---------------------------------------------------------------------------

    The committee concluded that if an increase in fuel economy were 
implemented pursuant to standards that are structured in a way that 
encourages either downsizing or the increased production of smaller 
vehicles, some additional traffic fatalities would be expected. Without 
a thoughtful restructuring of the program, there would be the trade-
offs that must be made if CAFE standards were increased by any 
significant amount.\16\
---------------------------------------------------------------------------

    \16\ NAS, p. 9.
---------------------------------------------------------------------------

    In response to these conclusions, NHTSA began issuing attribute-
based CAFE standards for light trucks and sought legislative authority 
to issue attribute-based CAFE standards for passenger cars before 
undertaking to raise the car standards. Congress went a step further in 
enacting EISA, not only authorizing the issuance of attribute-based 
standards, but also mandating them.
    Fully realizing all of the safety and other \17\ benefits of these 
reforms will depend in part on whether the unreformed, non-attribute 
based greenhouse standards adopted by California and other states are 
implemented. Apart from issues of relative stringency, the effects on 
vehicle manufacturers of implementing those state emission standards 
should be substantially similar to the effects of implementing non-
attribute-based CAFE standards, given the nearly identical nature of 
most aspects of those emission standards and CAFE standards in terms of 
technological means of compliance and methods of measuring performance.
---------------------------------------------------------------------------

    \17\ Reformed CAFE has several advantages compared to Unreformed 
CAFE:
    First, Reformed CAFE increases energy savings. The energy-saving 
potential of Unreformed CAFE is limited because only a few full-line 
manufacturers are required to make improvements. Under Reformed 
CAFE, which accounts for size differences in product mix, virtually 
all manufacturers will be required to use advanced fuel-saving 
technologies to achieve the requisite fuel economy for their 
automobiles.
    Second, Reformed CAFE reduces the chances of adverse safety 
consequences. Downsizing of vehicles as a CAFE compliance strategy 
is discouraged under Reformed CAFE since as vehicles become smaller, 
the applicable fuel economy target becomes more stringent.
    Third, Reformed CAFE provides a more equitable regulatory 
framework for different vehicle manufacturers. Under Unreformed 
CAFE, the cost burdens and compliance difficulties have been imposed 
nearly exclusively on the full-line manufacturers.
    Fourth, Reformed CAFE is more market-oriented because it more 
fully respects economic conditions and consumer choice. Reformed 
CAFE does not force vehicle manufacturers to adjust fleet mix toward 
smaller vehicles although they can make adjustments if that is what 
consumers are demanding. Instead, it allows the manufacturers to 
adjust the mix of their product offerings in response to the market 
place.
---------------------------------------------------------------------------

b. Environmental and Other Externalities Justify Increasing the CAFE 
Standards
    The 2002 NAS report also concluded that the CAFE standards have 
contributed to increased fuel economy, which in turn has reduced 
dependence on imported oil, improved the nation's terms of trade, and 
reduced emissions of carbon dioxide (a principal greenhouse gas), 
relative to what they otherwise would have been. If fuel economy had 
not improved, gasoline consumption (and crude oil imports) would be 
about 2.8 million barrels per day (mmbd) greater than it is.\18\ 
Reducing fuel consumption in vehicles also reduces carbon dioxide 
emissions. If the nation were using 2.8 mmbd more gasoline, carbon 
emissions would be more than 100 million metric tons of carbon (mmtc) 
higher. Thus, improvements in light-duty vehicle (4 wheeled motor 
vehicles under 10,000 pounds gross vehicle weight rating) fuel economy 
have reduced overall U.S. emissions by about 7 percent.\19\
---------------------------------------------------------------------------

    \18\ NAS, pp. 3 and 20.
    \19\ NAS, p. 20.
---------------------------------------------------------------------------

    The report concluded that technologies exist that could 
significantly further reduce fuel consumption by passenger cars and 
light trucks within 15 years, while maintaining vehicle size, weight, 
utility and performance.\20\ Light duty trucks

[[Page 24360]]

were said to offer the greatest potential for reducing fuel 
consumption.\21\ The report also noted that vehicle development 
cycles--as well as future economic, regulatory, safety and consumer 
preferences--would influence the extent to which these technologies 
could lead to increased fuel economy in the U.S. market. To assess the 
economic trade-offs associated with the introduction of existing and 
emerging technologies to improve fuel economy, the NAS conducted what 
it called a ``cost-efficient analysis'' based on the direct benefits 
(value of saved fuel) to the consumer--``that is, the committee 
identified packages of existing and emerging technologies that could be 
introduced over the next 10 to 15 years that would improve fuel economy 
up to the point where further increases in fuel economy would not be 
reimbursed by fuel savings.'' \22\
---------------------------------------------------------------------------

    \20\ NAS, p. 3 (Finding 5).
    \21\ NAS, p. 4 (Finding 5).
    \22\ NAS, pp. 4 (Finding 6) and 64.
---------------------------------------------------------------------------

    The committee emphasized that it is critically important to be 
clear about the reasons for considering improved fuel economy. While 
the dollar value of the saved fuel would be largest portion of the 
potential benefits, the committee noted that there is theoretically 
insufficient reason for the government to issue higher standards just 
to obtain those direct benefits since consumers have a wide variety of 
opportunities to buy a fuel-efficient vehicle.\23\
---------------------------------------------------------------------------

    \23\ NAS, pp. 8-9.
---------------------------------------------------------------------------

    The committee said that there are two compelling concerns that 
justify a government mandated increase in fuel economy, both relating 
to externalities. The most important concern, it argued, is the one 
about the accumulation in the atmosphere of greenhouse gases, 
principally carbon dioxide.\24\
---------------------------------------------------------------------------

    \24\ NAS, pp. 2, 13, and 83.
---------------------------------------------------------------------------

    A second concern is that petroleum imports have been steadily 
rising because of the nation's increasing demand for gasoline without a 
corresponding increase in domestic supply. The high cost of oil imports 
poses two risks: Downward pressure on the strength of the dollar (which 
drives up the cost of goods that Americans import) and an increase in 
U.S. vulnerability to macroeconomic shocks that cost the economy 
considerable real output.
    To determine how much the fuel economy standards should be 
increased, the committee urged that all social benefits be considered. 
That is, it urged not only that the dollar value of the saved fuel be 
considered, but also that the dollar value to society of the resulting 
reductions in greenhouse gas emissions and in dependence on imported 
oil should be calculated and considered. The committee said that if it 
is possible to assign dollar values to these favorable effects, it 
becomes possible to make at least crude comparisons between the 
socially beneficial effects of measures to improve fuel economy on the 
one hand, and the costs (both out-of-pocket and more subtle) on the 
other. The committee chose a value of about $0.30/gal of gasoline for 
the externalities associated with the combined impacts of fuel 
consumption on greenhouse gas emissions and on world oil market 
conditions.\25\
---------------------------------------------------------------------------

    \25\ NAS, pp. 4 and 85-86.
---------------------------------------------------------------------------

    The report expressed concerns about increasing the standards under 
the CAFE program as currently structured. While raising CAFE standards 
under the existing structure would reduce fuel consumption, doing so 
under alternative structures ``could accomplish the same end at lower 
cost, provide more flexibility to manufacturers, or address inequities 
arising from the present'' structure.\26\ Further, the committee said, 
``to the extent that the size and weight of the fleet have been 
constrained by CAFE requirements * * * those requirements have caused 
more injuries and fatalities on the road than would otherwise have 
occurred.'' \27\ Specifically, it noted: ``The downweighting and 
downsizing that occurred in the late 1970s and early 1980s, some of 
which was due to CAFE standards, probably resulted in an additional 
1300 to 2600 traffic fatalities in 1993.'' \28\
---------------------------------------------------------------------------

    \26\ NAS, pp. 4-5 (Finding 10).
    \27\ NAS, p. 29.
    \28\ NAS, p. 3 (Finding 2).
---------------------------------------------------------------------------

    To address those structural problems, the report suggested various 
possible reforms. The report found that the ``CAFE program might be 
improved significantly by converting it to a system in which fuel 
targets depend on vehicle attributes.'' \29\ The report noted further 
that under an attribute-based approach, the required CAFE levels could 
vary among the manufacturers based on the distribution of their product 
mix. NAS stated that targets could vary among passenger cars and among 
trucks, based on some attribute of these vehicles such as weight, size, 
or load-carrying capacity. The report explained that a particular 
manufacturer's average target for passenger cars or for trucks would 
depend upon the fractions of vehicles it sold with particular levels of 
these attributes.\30\
---------------------------------------------------------------------------

    \29\ NAS, p. 5 (Finding 12).
    \30\ NAS, p. 87.
---------------------------------------------------------------------------

    In February 2002, Secretary Mineta asked Congress ``to provide the 
Department of Transportation with the necessary authority to reform the 
CAFE program, guided by the NAS report's suggestions.''
2. Final Rule Establishing Reformed (Attribute-Based) CAFE Standards 
for MY 2008-2011 Light Trucks (March 2006)
    The 2006 final rule reformed the structure of the CAFE program for 
light trucks and established higher CAFE standards for MY 2008-2011 
light trucks.\31\ Reforming the CAFE program enables it to achieve 
larger fuel savings, while enhancing safety and preventing adverse 
economic consequences.
---------------------------------------------------------------------------

    \31\ 71 FR 17566; April 6, 2006.
---------------------------------------------------------------------------

    During a transition period of MYs 2008-2010, manufacturers may 
comply with CAFE standards established under the reformed structure 
(Reformed CAFE) or with standards established in the traditional way 
(Unreformed CAFE). This permits manufacturers and the agency to gain 
experience with implementing the Reformed CAFE standards. Under the 
2006 rule, all manufacturers were required to comply with a Reformed 
CAFE standard in MY 2011.
    Under Reformed CAFE, fuel economy standards were restructured so 
that they are based on a measure of vehicle size called ``footprint,'' 
which is the product of multiplying a vehicle's wheelbase by average 
its track width. A target level of fuel economy was established for 
each increment in footprint (0.1 ft\2\). Trucks with smaller footprints 
have higher fuel economy targets; conversely, larger ones have lower 
targets. A particular manufacturer's compliance obligation for a model 
year will be calculated as the harmonic average of the fuel economy 
targets for the manufacturer's vehicles, weighted by the distribution 
of manufacturer's production volumes among the footprint increments. 
Thus, each manufacturer will be required to comply with a single 
overall average fuel economy level for each model year of production.
    The approach for determining the fuel economy targets was to set 
them just below the level where the increased cost of technologies that 
could be adopted by manufacturers to improve fuel economy would first 
outweigh the added benefits that would result from such technology. 
These targets translate into required levels of average fuel economy 
that are technologically feasible because manufacturers can achieve 
them using available technologies. Those levels also reflect the need 
of the nation to reduce

[[Page 24361]]

energy consumption because they reflect the economic value of the 
savings in resources, as well as of the reductions in economic and 
environmental externalities that result from producing and using less 
fuel.
    The Unreformed CAFE standards are: 22.5 miles per gallon (mpg) for 
MY 2008, 23.1 mpg for MY 2009, and 23.5 mpg for MY 2010. To aid the 
transition to Reformed CAFE, the Reformed CAFE standards for those 
years were set at levels intended to ensure that the industry-wide 
costs of the Reformed standards are roughly equivalent to the industry-
wide costs of the Unreformed CAFE standards in those model years. For 
MY 2011, the Reformed CAFE standard was set at the level that maximizes 
net benefits. Net benefits include the increase in light truck prices 
due to technology improvements, the decrease in fuel consumption, and a 
number of other factors. All of the standards were set at the maximum 
feasible level, while accounting for technological feasibility, 
economic practicability and other relevant factors.
    We carefully balanced the costs of the rule with the benefits of 
reducing energy consumption. Compared to Unreformed CAFE, Reformed CAFE 
enhances overall fuel savings while providing vehicle manufacturers 
with the flexibility they need to respond to changing market 
conditions. Reformed CAFE will also provide a more equitable regulatory 
framework by creating a level-playing field for manufacturers, 
regardless of whether they are full-line or limited-line manufacturers. 
We were particularly encouraged that Reformed CAFE will eliminate the 
incentive to downsize some of their fleet as a CAFE compliance 
strategy, thereby reducing the adverse safety risks associated with the 
Unreformed CAFE program.
3. Twenty-in-Ten Initiative (January 2007)
    In his January 2007 State of the Union address, the President 
announced his Twenty-in-Ten initiative for increasing the supply of 
renewable and alternative fuels and reforming and increasing the CAFE 
standards. Consistent with the NAS report, he urged the authority be 
provided to reform CAFE for passenger cars by adopting an attribute-
based system (for example, a size-based system) reduces the risk that 
vehicle safety is compromised, helps preserve consumer choice, and 
helps spread the burden of compliance across all product lines and 
manufacturers. He also urged that authority be provided to set the CAFE 
standards, based on cost/benefit analysis, using sound science, and 
without impacting safety.
4. Request for Passenger Car and Light Truck Product Plans (February 
2007)
    In late February 2007, NHTSA published a notice to acquire new and 
updated information regarding vehicle manufacturers' future product 
plans to aid in implementing the President's plan for reforming and 
increasing CAFE standards for passenger cars and further increasing the 
already reformed light truck standards. More specifically, the agency 
said:

    * * * we are seeking information related to fuel economy 
improvements for MY 2007-2017 passenger cars and MY 2010-2017 light 
trucks. The agency is seeking information in anticipation of 
obtaining statutory authority to reform the passenger car CAFE 
program and to set standards under that structure for MY 2010-2017 
passenger cars. The agency is also seeking this information in 
anticipation of setting standards for MY 2012-2017 light trucks.\32\
---------------------------------------------------------------------------

    \32\ 72 FR 8664; February 27, 2007.
---------------------------------------------------------------------------

5. Supreme Court Decision in Massachusetts v. EPA (April 2007)
    On April 2, 2007, the U.S. Supreme Court issued its opinion in 
Massachusetts v. EPA.\33\ The Court ruled that the state of 
Massachusetts had standing because it had already lost a small amount 
of land and stood to lose more due to global warming induced increases 
in sea level; that some portion of this harm was traceable to the 
absence of a regulation issued by EPA requiring reductions in GHG 
emissions (CO2 emissions, most notably) by motor vehicles; 
and that issuance of such an EPA regulation by EPA would reduce the 
risk of further harm to Massachusetts. On the merits, the Court ruled 
that greenhouse gases are ``pollutants'' under the Clean Air Act and 
that the Act therefore authorizes EPA to regulate greenhouse gas 
emissions from motor vehicles if EPA makes the necessary findings and 
determinations under section 202 of the Act.
---------------------------------------------------------------------------

    \33\ 127 S.Ct. 1438 (2007).
---------------------------------------------------------------------------

    The Court considered EPCA briefly, noting that it and the Clean Air 
Act have different overall purposes. It noted further that the two acts 
overlap, but did not define the nature or extent of that overlap. It 
concluded that EPCA did not relieve EPA of its statutory obligations 
and expressed confidence that the two acts could be consistently 
administered. The Court did not address the express preemption 
provision in EPCA.
6. Coordination Between NHTSA and EPA on Development of Rulemaking 
Proposals (Summer-Fall 2007)
    In the wake of the Supreme Court's decision and in the absence of 
the legislation he called for in his 2007 State of the Union message, 
the President called on NHTSA and EPA to take the first steps toward 
regulations that would cut gasoline consumption and greenhouse gas 
emissions from motor vehicles, using his Twenty-in-Ten initiative as a 
starting point. He asked them ``to listen to public input, to carefully 
consider safety, science, and available technologies, and evaluate the 
benefits and costs before they put forth the new regulation.'' He also 
issued an executive order directing all of the departments and agencies 
to work together on the proposal.
    Pursuant to the President's directive, NHTSA and EPA staff jointly 
assessed which technologies would be available and their effectiveness 
and cost. They also jointly assessed the key economic and other 
assumptions affecting the stringency of future standards. Finally, they 
worked together in updating and further improving the Volpe model that 
had been used to help determine the stringency of the MY 2008-2011 
light truck CAFE standards. Much of the work between NHTSA and EPA 
staff was reflected in rulemaking proposals being developed by NHTSA 
prior to the enactment of EISA and was substantially retained when 
NHTSA revised its proposals to be consistent with that legislation. 
Ultimately, the proposals being published today are based on NHTSA's 
assessments of how they meet EPCA, as amended by EISA.
7. Ninth Circuit Decision Re Final Rule for MY 2008-2011 Light Trucks 
(November 2007)
    On November 15, 2007, the United States Court of Appeals for the 
Ninth Circuit issued its decision in Center for Biological Diversity v. 
NHTSA,\34\ the challenge to the MY 2008-11 light truck CAFE rule. The 
Court rejected the petitioners' argument that EPCA precludes the use of 
a marginal cost-benefit analysis that attempted to weigh all of the 
social benefits (i.e., externalities as well as direct benefits to 
consumers) of improved fuel savings in determining the stringency of 
the CAFE standards. It cautioned, however, that it had not reviewed 
whether the agency's balancing of the statutory factors in setting 
those standards was arbitrary and capricious. In that regard, it noted 
that much had changed since a court of appeals had last (i.e., in the 
late 1980's) reviewed the agency's balancing of those factors in a 
rulemaking. Specifically, it noted increases in scientific knowledge of 
climate change

[[Page 24362]]

and in the need to reduce importation of petroleum since that time.
---------------------------------------------------------------------------

    \34\ 508 F.3d 508.
---------------------------------------------------------------------------

    Further, the Court found that NHTSA had been arbitrary and 
capricious in its treatment of the following issues:
     NHTSA's decision not to monetize the benefit of reducing 
CO2 emissions and use that value in conducting its marginal 
benefit-cost analysis based on its view that the value of the benefit 
of CO2 emission reductions resulting from fuel consumption 
reductions was too uncertain to permit the agency to determine a value 
for those emission reductions;\35\
---------------------------------------------------------------------------

    \35\ The agency has developed a value for those reductions and 
used it in the analyses underlying the standards proposed in this 
NPRM. For further discussion, see section V of this preamble.
---------------------------------------------------------------------------

     NHTSA's decision not to establish a ``backstop'' (i.e., a 
fixed minimum CAFE standard applicable to manufacturers); \36\
---------------------------------------------------------------------------

    \36\ EISA's requirement that standards be based on one or more 
vehicle attributes and its specification for domestic passenger 
cars, but not for nondomestic passenger cars or light trucks of an 
absolute CAFE level appear to preclude the specification of such a 
backstop standard for the latter two categories of automobiles. For 
further discussion, see Section VI of this preamble.
---------------------------------------------------------------------------

     NHTSA's decision not to proceed to revise the regulatory 
definitions for the passenger car and light truck categories of 
automobiles so that some vehicles currently classified as light trucks 
are instead classified as passenger cars; \37\
---------------------------------------------------------------------------

    \37\ In this NPRM, NHTSA examines the legislative history of the 
statutory definitions of ``automobile'' and ``passenger automobile'' 
and the term ``nonpassenger automobile'' and analyses the impact of 
that moving any vehicles out of the nonpassenger automobile (light 
truck) category into the passenger automobile (passenger car) 
category would have the level of standards for both groups of 
automobiles. For further discussion, see Section VIII of this 
preamble.
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     NHTSA's decision not to subject most medium- and heavy-
duty pickups and most medium- and heavy-duty cargo vans (i.e., those 
between 8,500 and 10,000 pounds gross vehicle weight rating (GVWR,) to 
the CAFE standards; \38\
---------------------------------------------------------------------------

    \38\ EISA removed these vehicles from the statutory definition 
of ``automobile'' and mandated the establishment of CAFE standards 
for them following the completion of reports by the National Academy 
of Sciences and NHTSA.
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     NHTSA's limited assessment of cumulative impacts and 
regulatory alternatives in its Environmental Assessment (EA) under the 
National Environmental Policy Act (NEPA), and its decision to prepare 
and publish an EA, coupled with a finding of no significant impact, 
instead of an Environmental Impact Statement (EIS).\39\
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    \39\ On February 9, NHTSA filed a petition with the Ninth 
Circuit for rehearing en banc on the issue of whether the panel in 
CBD acted within its authority in ordering the agency to prepare an 
EIS instead of remanding the issue to the agency and directing it to 
conduct a new, fuller environmental analysis and decide whether an 
EIS is required. In addition, NHTSA has published a notice of intent 
to prepare an environmental impact statement, thus beginning the EIS 
process for this rulemaking, as discussed in Section XIII.B. of this 
NPRM.
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    The Court did not vacate the standards, but instead said it would 
remand the rule to NHTSA to promulgate new standards consistent with 
its opinion ``as expeditiously as possible and for the earliest model 
year practicable.\40\ Under the decision, the standards established by 
the April 2006 final rule would remain in effect unless and until 
amended by NHTSA.
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    \40\ The deadline in EPCA for issuing a final rule establishing, 
for the first time, a CAFE standard for a model year is 18 months 
before the beginning of that model year. 49 U.S.C. 32902(g)(2). The 
same deadline applies to issuing a final rule amending an existing 
CAFE standard so as to increase its stringency. Given that the 
agency has long regarded October 1 as the beginning of a model year, 
the statutory deadline for increasing the MY 2009 standard was March 
30, 2007, and the deadline for increasing the MY 2010 standard is 
March 30, 2008. Thus, the only model year for which there is 
sufficient time to gather all of the necessary information, conduct 
the necessary analyses and complete a rulemaking is MY 2011. As 
noted earlier in this document, however, EISA requires that a new 
standard be established for that model year. This rulemaking is 
being conducted pursuant to that requirement.
---------------------------------------------------------------------------

    On February 6, 2008, the Government petitioned for en banc 
rehearing by the Ninth Circuit on the limited issue of whether it was 
appropriate for the panel, having held that the agency insufficiently 
explored the environmental implications of the MY 2008-11 rulemaking in 
its EA, to order the agency to prepare an EIS rather than simply 
remanding the matter to the agency for further analysis.
    As of the date of the issuance of this proposal, the Court has not 
yet issued its mandate in this case.
8. Enactment of Energy Security and Independence Act of 2007 (December 
2007)
    As noted above in section I.B., EISA significantly changed the 
provisions of EPCA governing the establishment of future CAFE 
standards. These changes made it necessary for NHTSA to pause in its 
efforts so that it could assess the implications of the amendments made 
by EISA and then, as required, revise some aspects of the proposals it 
had been developing (e.g., the model years covered and credit issues).

C. Energy Policy and Conservation Act, as Amended

    EPCA, which was enacted in 1975, mandates a motor vehicle fuel 
economy regulatory program to improve the nation's energy security and 
energy efficiency. It gives the authority under EPCA to regulate fuel 
economy to DOT, which has delegated that authority to NHTSA at 49 CFR 
1.50. EPCA allocates the responsibility for implementing the program as 
follows: NHTSA sets CAFE standards for passenger cars and light trucks; 
EPA calculates the average fuel economy of each manufacturer's 
passenger cars and light trucks; and NHTSA enforces the standards based 
on EPA's calculations.
    We have summarized below EPCA, as amended by EISA. We request 
comment on how EPCA should be implemented to achieve the goals and meet 
the requirements of EISA. For example, what assumptions, methodologies 
and computations should be used in establishing and implementing the 
new standards?
1. Vehicles Subject to Standards for Automobiles
    With two exceptions, all four-wheeled motor vehicles with a gross 
vehicle weight rating of 10,000 pounds or less will be subject to the 
CAFE standards, beginning with MY 2011. The exceptions will be work 
trucks \41\ and multi-stage vehicles. Work trucks are defined as 
vehicles that are:
---------------------------------------------------------------------------

    \41\ While EISA excluded work trucks from ``automobiles,'' it 
did not exclude them from regulation under EPCA. EISA requires that 
work trucks be subjected to CAFE standards, but only first after the 
National Academy of Sciences completes a study and then after NHTSA 
completes a follow-on study. Congress thus recognized and made 
allowances for the practical difficulties that led NHTSA to decline 
to include work trucks in its final rule for MY 2008-11 light 
trucks.

--rated at between 8,500 and 10,000 pounds gross vehicle weight; and
--are not a medium-duty passenger vehicle (as defined in section 
86.1803-01 of title 40, Code of Federal Regulations, as in effect on 
the date of the enactment of the Ten-in-Ten Fuel Economy Act).\42\
---------------------------------------------------------------------------

    \42\ 49 U.S.C. 32902(a)(19).

Medium-duty passenger vehicles (MDPV) include 8,500 to 10,000 lb. GVWR 
sport utility vehicles (SUVs), short bed pick-up trucks, and passenger 
vans, but exclude pickup trucks with longer beds and cargo vans rated 
at between 8,500 and 10,000 lbs GVWR. It is those excluded pickup 
trucks and cargo vans that are work trucks. ``Multi-stage vehicle'' 
includes any vehicle manufactured in different stages by 2 or more 
manufacturers, if no intermediate or final-stage manufacturer of that 
vehicle manufactures more than 10,000 multi-stage vehicles per 
year.\43\
---------------------------------------------------------------------------

    \43\ 49 U.S.C. 32902(a)(3).
---------------------------------------------------------------------------

    Under EPCA, as it existed before EISA, the agency had discretion 
whether to regulate vehicles with a GVWR between 6,000 and 10,000 lbs., 
GVWR. It could regulate the fuel

[[Page 24363]]

economy of vehicles with a GVWR within that range under CAFE if it 
determined that (1) standards were feasible for these vehicles, and (2) 
either (a) that these vehicles were used for the same purpose as 
vehicles rated at not more than 6,000 lbs. GVWR, or (b) that their 
regulation would result in significant energy conservation.
    EISA eliminated the need for administrative determinations in order 
to subject vehicles between 6,000 and 10,000 lbs. GVWR to the CAFE 
standards for automobiles. Congress did so by making the determination 
itself that all vehicles within that GVWR range should be included, 
with the exceptions noted above.
2. Mandate To Set Standards for Automobiles
    As amended by EISA, EPCA requires that the agency establish 
standards for all new automobiles for each model year at the maximum 
feasible levels for that model year. A manufacturer's individual 
passenger cars and light trucks are not required to meet a particular 
fuel economy level. Instead, the harmonically averaged fuel economy of 
a manufacturer's production of passenger cars (or light trucks) in a 
particular model year must meet the standard for those automobiles for 
that model year.
    For model years 2011-2020, several special requirements, in 
addition to the maximum feasible requirement, are specified.\44\ Each 
of the requirements must be interpreted in light of the other 
requirements. For those model years, separate standards for passenger 
cars and for light trucks must be set at high enough levels to ensure 
that the CAFE of the industry wide combined fleet of new passenger cars 
and light trucks for MY 2020 is not less than 35 mpg. The 35 mpg figure 
is not a standard applicable to any individual manufacturer. It is a 
requirement, applicable to the agency, regarding the combined effect of 
the separate standards for passenger cars and light trucks that NHTSA 
is to establish for MY 2020. EISA does not specify precisely how 
compliance with this requirement is to be ensured or how or when the 
CAFE of the industry wide combined fleet for MY 2020 is to be 
calculated for purposes of determining compliance. As a practical 
matter, to ensure that this level is achieved, the standard for MY 2020 
passenger cars would have to be above 35 mpg and the one for MY 2020 
light trucks might or might not be below 35 mpg. Similarly, the CAFE of 
some manufacturers' combined fleet of passenger cars and light trucks 
would be above 35 mpg, while the combined fleet of others might or 
might not be below 35 mpg. The standards for passenger cars and those 
for light trucks must increase ratably each year. The CAFE of each 
manufacturer's fleet of domestic passenger cars must meet a sliding, 
absolute minimum level in each model year: 27.5 mpg or 92 percent of 
the projected CAFE of the industry wide fleet of new domestic passenger 
cars for that model year.
---------------------------------------------------------------------------

    \44\ Under EPCA, prior to its amendment by EISA, the standard 
for passenger cars was 27.5 mpg unless amended to a higher or lower 
level by DOT. Per EISA, the standard will remain at 27.5 mpg through 
MY 2010.
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    EPCA, as it existed before EISA, EPCA required that light truck 
standards be set at the maximum feasible level for each model year, but 
simply specified a default standard of 27.5 mpg for passenger cars for 
MY 1985 and thereafter. It permitted, but did not require that NHTSA 
establish a higher or lower standard for passenger cars if the agency 
found that the maximum feasible level of fuel economy is higher or 
lower than 27.5 mpg.
3. Structure of Standards
    The standards for passenger cars and light trucks must be based on 
one or more vehicle attributes and expressed in terms of a mathematical 
function. This makes it possible to increase the CAFE standards for 
both passenger cars and light trucks significantly without creating 
incentives to improve fuel economy in ways that reduce safety. 
Formerly, EPCA provided authority for this approach for light trucks, 
but not passenger cars.
4. Factors Governing or Considered in the Setting of Standards
    In determining the maximum feasible level of average fuel economy 
for a model year, EPCA requires that the agency consider four factors: 
technological feasibility, economic practicability, the effect of other 
standards of the Government on fuel economy, and the need of the nation 
to conserve energy. EPCA does not define these terms or specify what 
weight to give each concern in balancing them; thus, NHTSA defines them 
and determines the appropriate weighting based on the circumstances in 
each CAFE standard rulemaking.
    ``Technological feasibility'' means whether a particular method of 
improving fuel economy can be available for commercial application in 
the model year for which a standard is being established.
    ``Economic practicability'' means whether a standard is one 
``within the financial capability of the industry, but not so stringent 
as to'' lead to ``adverse economic consequences, such as a significant 
loss of jobs or the unreasonable elimination of consumer choice.'' \45\ 
In an attempt to ensure the economic practicability of attribute based 
standards, the agency considers a variety of factors, including the 
annual rate at which manufacturers can increase the percentage of its 
fleet that has a particular type of fuel saving technology, and cost to 
consumers. Since consumer acceptability is an element of economic 
practicability, the agency has limited its consideration of fuel saving 
technologies to be added to vehicles to those that provide benefits 
that match their costs. Disproportionately expensive technologies are 
not likely to be accepted by consumers.
---------------------------------------------------------------------------

    \45\ 67 FR 77015, 77021; December 16, 2002.
---------------------------------------------------------------------------

    At the same time, the law does not preclude a CAFE standard that 
poses considerable challenges to any individual manufacturer. The 
Conference Report for EPCA, as enacted in 1975, makes clear, and the 
case law affirms, ``(A) determination of maximum feasible average fuel 
economy should not be keyed to the single manufacturer which might have 
the most difficulty achieving a given level of average fuel 
economy.''\46\ Instead, the agency is compelled ``to weigh the benefits 
to the nation of a higher fuel economy standard against the 
difficulties of individual automobile manufacturers.'' Id. The law 
permits CAFE standards exceeding the projected capability of any 
particular manufacturer as long as the standard is economically 
practicable for the industry as a whole. Thus, while a particular CAFE 
standard may pose difficulties for one manufacturer, it may also 
present opportunities for another. The CAFE program is not necessarily 
intended to maintain the competitive positioning of each particular 
company. Rather, it is intended to enhance fuel economy of the vehicle 
fleet on American roads, while protecting motor vehicle safety and the 
totality of American jobs and the overall United States economy.
---------------------------------------------------------------------------

    \46\ CEI-I, 793 F.2d 1322, 1352 (DC Cir. 1986).
---------------------------------------------------------------------------

    ``The effect of other motor vehicle standards of the Government on 
fuel economy'' means ``the unavoidable adverse effects on fuel economy 
of compliance with emission, safety, noise, or damageability 
standards.'' In the case of emission standards, this includes standards 
adopted by the Federal government and can include standards adopted by 
the States as well, since in certain circumstances the Clean Air Act

[[Page 24364]]

permits States to adopt and enforce State standards in lieu of the 
Federal ones. It does not, however, include State standards expressly 
preempted by EPCA.\47\
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    \47\ 49 U.S.C. 32919 and 71 FR 17566, 17654-70; April 6, 2006.
---------------------------------------------------------------------------

    ``The need of the United States to conserve energy'' means ``the 
consumer cost, national balance of payments, environmental, and foreign 
policy implications of our need for large quantities of petroleum, 
especially imported petroleum.'' Environmental implications principally 
include reductions in emissions of criteria pollutants and carbon 
dioxide. A prime example of foreign policy implications are energy 
independence and security concerns.
    The agency has considered environmental issues in making decisions 
about the setting of standards from the earliest days of the CAFE 
program. As the three courts of appeal have noted in decisions 
stretching over the last 20 years,\48\ the agency defined the ``need of 
the Nation to conserve energy'' in the late 1970's as including ``the 
consumer cost, national balance of payments, environmental, and foreign 
policy implications of our need for large quantities of petroleum, 
especially imported petroleum.'' \49\ Pursuant to that view, the agency 
declined to include diesel engines in determining the maximum feasible 
level of average fuel economy for passenger cars and for light trucks 
because particulate emissions from diesels were then both a source of 
concern and unregulated.\50\ In the late 1980's, NHTSA cited concerns 
about climate change as one of its reasons for limiting the extent of 
its reduction of the CAFE standard for MY 1989 passenger cars \51\ and 
for declining to reduce the standard for MY 1990 passenger cars.\52\ 
Since then, DOT has considered the indirect benefits of reducing 
tailpipe carbon dioxide emissions in its fuel economy rulemakings 
pursuant to the statutory requirement to consider the nation's need to 
conserve energy by reducing consumption. In this rulemaking, consistent 
with the Ninth Circuit's decision and its observations about the 
potential effect of changing information about climate change on the 
balancing of the EPCA factors and aided by the 2007 reports of the 
United Nations Intergovernmental Panel on Climate Change \53\ and other 
information, NHTSA is monetizing the reductions in tailpipe emissions 
of CO2 that will result from the CAFE standards and is 
proposing to set the MY 2011-15 CAFE standards at levels that reflect 
the value of those reductions in CO2. as well as the value 
of other benefits of those standards. In setting CAFE standards, NHTSA 
also considers environmental impacts under NEPA, 42 U.S.C. 4321-4347.
---------------------------------------------------------------------------

    \48\ Center for Auto Safety v. NHTSA, 793 F.2d 1322, 1325 n. 12 
(DC Cir. 1986); Public Citizen v. NHTSA, 848 F.2d 256, 262-3 n. 27 
(DC Cir. 1988) (noting that ``NHTSA itself has interpreted the 
factors it must consider in setting CAFE standards as including 
environmental effects''); and Center for Biological Diversity v. 
NHTSA, 508 F.3d 508, 529 (9th Cir. 2007).
    \49\ 42 FR 63,184, 63,188 (Dec. 15, 1977) (emphasis added).
    \50\ For example, the final rules establishing CAFE standards 
for MY 1981-84 passenger cars, 42 FR 33,533, 33,540-1 and 33,551; 
June 30, 1977, and for MY 1983-85 light trucks, 45 FR 81,593, 
81,597; December 11, 1980.
    \51\ 53 FR 39,275, 39,302; October 6, 1988.
    \52\ 54 FR 21985,
    \53\ The IPCC 2007 reports can be found at http://www.ipcc.ch/. 
(Last accessed April 20, 2008.)
---------------------------------------------------------------------------

    In addition, the agency is permitted to consider additional 
relevant societal considerations. For example, historically, it has 
considered the potential for adverse safety consequences when deciding 
upon a maximum feasible level. This practice is sanctioned in case 
law.\54\
---------------------------------------------------------------------------

    \54\ See, e.g., Center for Auto Safety v. NHTSA (CAS), 793 F. 2d 
1322 (DC Cir. 1986) (Administrator's consideration of market demand 
as component of economic practicability found to be reasonable); 
Public Citizen 848 F.2d 256 (Congress established broad guidelines 
in the fuel economy statute; agency's decision to set lower standard 
was a reasonable accommodation of conflicting policies). As the 
United States Court of Appeals pointed out in upholding NHTSA's 
exercise of judgment in setting the 1987-1989 passenger car 
standards, ``NHTSA has always examined the safety consequences of 
the CAFE standards in its overall consideration of relevant factors 
since its earliest rulemaking under the CAFE program.'' Competitive 
Enterprise Institute v. NHTSA (CEI I), 901 F.2d 107, 120 at n.11 (DC 
Cir. 1990).
---------------------------------------------------------------------------

    EPCA requires that the MY 2011-2019 CAFE standards for passenger 
cars and for light trucks must both increase ratably to at least the 
levels necessary to meet 35 mpg requirement for MY 2020. NHTSA 
interprets this to mean that the standards must make steady progress 
toward the levels necessary for the average fuel economy of the 
combined industry wide fleet of all new passenger cars and light trucks 
sold in the United States during MY 2020 to reach at least 35 mpg.
    Finally, EPCA provides that in determining the level at which it 
should set CAFE standards for a particular model year, NHTSA may not 
consider the ability of manufacturers to take advantage of several EPCA 
provisions that facilitate compliance with the CAFE standards and 
thereby reduce the costs of compliance. As noted below in Section II, 
manufacturers can earn compliance credits by exceeding the CAFE 
standards and then use those credits to achieve compliance in years in 
which their measured average fuel economy falls below the standards. 
Manufacturers can also increase their CAFE levels through MY 2019 by 
producing alternative fuel vehicles. EPCA provides an incentive for 
producing these vehicles by specifying that their fuel economy is to be 
determined using a special calculation procedure that results in those 
vehicles being assigned a high fuel economy level.
5. Consultation in Setting Standards
    EPCA provides that NHTSA is to consult with the Department of 
Energy (DOE) and Environmental Protection Agency in prescribing CAFE 
standards. It provides further that NHTSA is to provide DOE with an 
opportunity to provide written comments on draft proposed and final 
CAFE standards.\55\
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    \55\ In addition, Executive Order No. 13432 provides that a 
Federal agency undertaking a regulatory action that can reasonably 
be expected to directly regulate emissions, or to substantially and 
predictably affect emissions, of greenhouse gases from motor 
vehicles, shall act jointly and consistently with other agencies to 
the extent possible and to consider the views of other agencies 
regarding such action.
---------------------------------------------------------------------------

6. Compliance Flexibility and Enforcement
    EPCA specifies a precise formula for determining the amount of 
civil penalties for failure to comply with a standard. The penalty, as 
adjusted for inflation by law, is $5.50 for each tenth of a mpg that a 
manufacturer's average fuel economy falls short of the standard for a 
given model year multiplied by the total volume of those vehicles in 
the affected fleet (i.e., import or domestic passenger car, or light 
truck), manufactured for that model year. The amount of the penalty may 
not be reduced except under the unusual or extreme circumstances 
specified in the statute.
    Likewise, EPCA provides that manufacturers earn credits for 
exceeding a standard. The amount of credit earned is determined by 
multiplying the number of tenths of a mpg by which a manufacturer 
exceeds a standard for a particular category of automobiles by the 
total volume of automobiles of that category manufactured by the 
manufacturer for a given model year.
    EPA is responsible for measuring automobile manufacturers' CAFE so 
that NHTSA can determine compliance with the CAFE standards. In making 
these measurements for passenger cars, EPA is required by EPCA \56\ to 
use the EPA test

[[Page 24365]]

procedures in place as of 1975 (or procedures that give comparable 
results), which are the city and highway tests of today, with 
adjustments for procedural changes that have occurred since 1975.
---------------------------------------------------------------------------

    \56\ 49 U.S.C. 32904(c).
---------------------------------------------------------------------------

    EPA's fuel economy test procedures specify equations for 
calculating fuel economy. These equations are based on the carbon 
balance technique which allows fuel economy to be determined from 
measurement of exhaust emissions. This technique relies upon the 
premise that the quantity of carbon in a vehicle's exhaust gas is equal 
to the quantity of carbon consumed by the engine as fuel.
    When NHTSA finds that a manufacturer is not in compliance, it 
notifies the manufacturer. Surplus credits generated from the five 
previous years can be used to make up the deficit. If there are no (or 
not enough) credits available, then the manufacturer can either pay the 
fine, or submit a carry back plan to the agency. A carry back plan 
describes what the manufacturer plans to do in the following three 
model years to make up for the deficit in credits. NHTSA must examine 
and determine whether to approve the plan.

III. Fuel Economy Enhancing Technologies

    In the Agency's last two rulemakings covering light truck CAFE 
standards for MYs 2005-2007 and MYs 2008-2011, the agency relied on the 
2002 National Academy of Sciences' report, Effectiveness and Impact of 
Corporate Average Fuel Economy Standards (``the 2002 NAS Report'') \57\ 
for estimating potential fuel economy benefits and associated retail 
costs of applying combinations of technologies in 10 classes of 
production vehicles. The NAS cost and effectiveness numbers were the 
best available estimates at this time, determined by a panel of experts 
formed by the National Academy of Sciences, and the report had been 
peer reviewed by individuals chosen for their diverse perspectives and 
technical expertise in accordance with procedures approved by the 
Report Review Committee of the National Research Council. However, 
since the publication of the 2002 NAS Report, there has been 
substantial advancement in fuel-saving technologies, including 
technologies not discussed in the NAS Report that are expected to 
appear on vehicles in the MY 2011-2015 timeframe. There also have been 
reports issued and studies conducted by several other organizations and 
companies that discuss fuel economy technologies and their benefits and 
costs. NHTSA has contracted with the NAS to update the fuel economy 
section, Chapter 3, of the 2002 NAS Report. However, this update will 
not be available in time for this rulemaking. Due to the expedited 
nature of this rulemaking, NHTSA, in consultation with the 
Environmental Protection Agency (EPA), developed an updated technology 
cost and effectiveness list to be used in this document.
---------------------------------------------------------------------------

    \57\ National Research Council, ``Effectiveness and Impact of 
Corporate Average Fuel Economy (CAFE) Standards,'' National Academy 
Press, Washington, DC (2002). Available at http://www.nap.edu/
openbook.php?isbn=0309076013 (last accessed April 20, 2008).
---------------------------------------------------------------------------

    This list presents NHTSA and EPA technical staff's current 
assessment of the costs and effectiveness from a broad range of 
technologies which can be applied to cars and light-duty trucks. EPA 
published the results of this collaboration in a report and submitted 
it to the NAS committee.\58\ A copy of the report and other studies 
used in the technology update will be placed in NHTSA's docket.
---------------------------------------------------------------------------

    \58\ EPA Staff Technical Report: Cost and Effectiveness 
Estimates of Technologies Used to Reduce Light-duty Vehicle Carbon 
Dioxide Emissions. EPA420-R-08-008, March, 2008.
---------------------------------------------------------------------------

    NHTSA believes that the estimates used for this document, which 
rely on the best available public and confidential information, are 
defensible and reasonable predictions for the next five years. 
Nevertheless, NHTSA still believes that the ideal source for this 
information comes from a peer reviewed process such as the NAS. NHTSA 
will continue to work with NAS to update this list on a five year 
interval as required by the Energy Independence and Security Act of 
2007.
    The majority of the technologies discussed in this section are in 
production and available on vehicles today, either in the United 
States, Japan, or Europe. A number of the technologies are commonly 
available, while others have only recently been introduced into the 
market. In a few cases, we provide estimates on technologies which are 
not currently in production, but are expected to be so in the next few 
years. These are technologies which can be applied to cars and trucks 
that are capable of achieving significant improvements in fuel economy 
and reductions in carbon dioxide emissions, and improve vehicle fuel 
economy, at reasonable costs.
    NHTSA and EPA conducted the technology examination using concepts 
from the 2002 NAS report which constituted a starting point for the 
analysis. In the NAS Report, there were three exemplary technology 
paths or scenarios identified for each class of production vehicles, 
which lead to successively greater improvements in fuel consumption and 
greater costs. Path I included production-intent technologies that will 
be available within 10 years and could be implemented under current 
economic and regulatory conditions. Path II included more costly 
production-intent technologies that are technically feasible for 
introduction within 10 years if economic and regulatory conditions 
justify their use. Path III included emerging technologies that will be 
available within 10 to 15 years but that may require further 
development prior to commercial introduction. These three paths 
represented vehicle development steps that would offer increasing 
levels of fuel economy gains (as incremental gains) at incrementally 
increasing cost. As stated earlier, since the publication of the 2002 
NAS Report, automotive technology has continued to advance and many of 
the technologies that were identified in the report as emerging have 
already entered the marketplace.
    In this rulemaking, NHTSA in consultation with EPA have examined a 
variety of technologies, looking beyond path I and path II to path III 
and to emerging technologies beyond path III. These technologies were 
in their infancy when the 2002 NAS Report was being formulated. In 
addition, unlike for past rulemakings where NHTSA projected the use of 
different variants of a technology as a combined technology, in this 
rulemaking, NHTSA working with EPA examined advanced forms and 
subcategories of existing technologies and reflected the effectiveness 
and cost for each of the variants separately for all ten vehicle 
classes. The specific technologies affected are variable valve timing 
(VVT), variable valve lift and timing (VVLT) and cylinder deactivation. 
Manufacturers are currently using many different types of VVTs and 
VVLTs, which have a variety of different names and methods. This 
rulemaking employs specific cost and effectiveness estimates for 
variants of VVT, including Intake Camshaft Phasing (ICP), Coupled 
Camshaft Phasing (CCP), and Dual (Independent) Camshaft Phasing (DCP). 
It also employs specific cost and effectiveness estimates for variants 
of VVLT, including Discrete Variable Valve Lift (DVVL) and Continuous 
Variable Valve Lift (CVVL). We also now include the effectiveness and 
cost estimates for each of the variants of cylinder deactivation. The 
most common type of cylinder deactivation is one in which an eight-
cylinder overhead

[[Page 24366]]

valve engine disables four of its cylinders under light loads. Cylinder 
deactivation could be incorporated on overhead cam engines, and can be 
applied to four and six cylinder engines as well (we have restricted 
application to 6 and 8 cylinder engines). Thus, the variants of 
cylinder deactivation that now have specific cost and effectiveness 
estimates include both overhead valve engine cylinder deactivation and 
overhead cam engine cylinder deactivation.
    The update also revisited technology lead time issues and took a 
fresh look at technology application rates, how to link certain 
technologies to certain redesign and refresh patterns, synergistic 
impacts resulting from adding technology packaging, and learning costs.

A. Data Sources for Technology Assumptions

    A large number of technical reports and papers are available which 
contain data and estimates of the fuel economy improvements of various 
vehicle technologies. In addition to specific peer-reviewed papers 
respecting individual technologies, we also utilized a number of recent 
reports which had been utilized by various State and Federal Agencies 
and which were specifically undertaken for the purpose of estimating 
future vehicle fuel economy reduction effectiveness or improvements in 
fuel economy. The reports we utilized most frequently were:
     2002 National Academy of Science (NAS) report titled 
``Effectiveness and Impact of Corporate Average Fuel Economy 
Standards''. At the time it was published, the NAS report was 
considered by many to be the most comprehensive summary of current and 
future fuel efficiencies improvements which could be obtained by the 
application of individual technologies. The focus of this report was 
fuel economy, which can be directly correlated with CO2 
emissions. The 2002 NAS report contains effectiveness estimates for ten 
different vehicle classifications (small car, mid-SUV, large truck, 
etc), but did not differentiate these effectiveness values across the 
classes. Where other sources or engineering principles indicated that a 
differentiation was warranted, we utilized the 2002 NAS effectiveness 
estimates as a starting point and further refined the estimate to one 
of the vehicle classes using engineering judgment or by consulting 
additional reliable sources.
     2004 Northeast States Center for a Clean Air Future 
(NESCCAF) report ``Reducing Greenhouse Gas Emissions from Light-Duty 
Motor Vehicles''. This report, which was utilized by the California Air 
Resources Board for their 2004 regulatory action on vehicle 
CO2 emissions, includes a comprehensive vehicle simulation 
study undertaken by AVL, a world-recognized leader in automotive 
technology and engineering. In addition, the report included cost 
estimates developed by the Martec Group, a market-based research and 
consulting firm which provides services to the automotive industry. The 
NESCCAF report considered a number of technologies not examined in the 
2002 NAS report. In addition, through the use of vehicle simulation 
modeling, the 2004 NESCCAF report provides a scientifically rigorous 
estimation of the synergistic impacts of applying multiple fuel economy 
technologies to a given vehicle.
     2006 Energy and Environmental Analysis Inc (EEA) report 
``Technology to Improve the Fuel Economy of Light Duty Trucks to 2015'' 
Prepared for The U.S. Department of Energy and The U.S. Department of 
Transportation. This update of technology characteristics is based on 
new data obtained by EEA from technology suppliers and auto-
manufacturers, and these data are compared to data from studies 
conducted earlier by EEA, the National Academy of Sciences (NAS), the 
Northeast States Center for a Clean Air future (NESCCAF) and California 
Air Resources Board (CARB).
     Data from Vehicle Manufacturers, Component Suppliers, and 
other reports. We also evaluated confidential data from a number of 
vehicle manufacturers as well as a number of technology component 
suppliers. In February of 2007, the NHTSA published a detailed Request 
for Comment (RFC) in the Federal Register. This RFC included, among 
other items, a request for information from automotive manufacturers 
and the public on the fuel economy improvement potential of a large 
number of vehicle technologies. The manufacturer's submissions to this 
RFC were supplemented by confidential briefing and data provided by 
vehicle component suppliers, who for many of the technologies 
considered are the actual manufacturers of the specific technology and 
often undertake their own development and testing efforts to 
investigate the fuel economy improvement potential of their products. 
Manufacturers that provided NHTSA and EPA with fuel economy cost and 
effectiveness estimates include BMW, Chrysler, Ford, General Motors, 
Honda, Nissan, Toyota and Volkswagen. The major suppliers that provided 
NHTSA with fuel economy cost and effectiveness estimates include Borg-
Warner, Bosch, Corning, Delphi, and Siemens.
     Finally, to verify that the fuel economy cost and 
effectiveness estimates for each of the technologies was reasonable and 
within currently available estimates for these technologies, NHTSA 
examined those estimates provided by other reports or sources, such as 
the Martec (contained in the 2004 NESCAFF report) and Sierra Research 
reports.\59\

B. Technologies and Estimates of Costs and Effectiveness

    This section describes each technology and associated cost and 
effectiveness numbers. The technologies can be classified into five 
main groups similar to how they were classified in the NAS Report: 
engine technologies; transmission technologies; accessory technologies; 
vehicle technologies; and hybrid technologies.
    While NHTSA and EPA followed the general approach taken by the NAS 
in estimating the cost and effectiveness numbers, we decided to update 
some of these estimates to reflect better the changed marketplace and 
regulatory environment, as well as the advancement in and greater 
penetration of some production-intent and emerging technologies, which 
have led to lower costs. The values contained in the 2002 NAS report 
were used to establish a baseline for the fuel economy cost and 
effectiveness estimates for each of the technologies. We then examined 
all other estimates provided by manufacturers and major suppliers or 
other sources. In examining these values, we gave more weight to values 
or estimates provided by manufacturers that have already implemented 
these technologies in their fleet, especially those that have 
introduced them in the largest quantities. Likewise, for technologies 
that have not penetrated the fleet to date, but will by early in the 
next decade (according to confidential manufacturer plans), we gave 
more weight to values or estimates provided by manufacturers that have 
stated that they will be introducing these technologies in their fleet, 
especially those that plan to introduce them in the largest quantities. 
In addition, for the technologies that will appear on vehicles by early 
in the next decade, we carefully examined the values provided

[[Page 24367]]

by those suppliers who have developed these technologies and may have 
contracts in place to provide them to manufacturers.
    Because not all technologies can be applied on all types of 
vehicles, engines or transmissions, we separately evaluated 10 classes 
of vehicles to estimate fuel economy cost and effectiveness for each of 
the technologies. As discussed above, these ten classes, also used in 
NHTSA's 2006 light truck CAFE rule, were derived from the 2002 NAS 
Report, which estimated the feasibility, potential incremental fuel 
consumption benefit and the incremental cost of three product 
development paths for the following ten vehicle classes: Subcompact 
passenger cars, compact passenger cars, midsize passenger cars, large 
passenger cars, small sport utility vehicles, midsize sport utility 
vehicles, large sport utility vehicles, small pickups, large pickups, 
and minivans.
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    \59\ ``Alternative and Future Technologies for Reducing 
Greenhouse Gas Emission from Road Vehicles'' Sierra Research Report 
for Environment Canada, 1999 (SR99-07-01). http://
www.sierraresearch.com/ReportListing.htm (Last accessed April 20, 
2008.)
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    The application of technologies to a vehicle class is limited not 
only by whether the manufacturer is capable of applying it within a 
particular development cycle, but also by whether the technology may 
physically be applied to the vehicle. For example, continuously 
variable transmissions (CVTs) were only allowed to be projected on 
vehicles with unibody construction, which includes all passenger cars 
and minivans and some small and midsize SUVs. CVTs could not be 
projected for use on vehicles with ladder-frame construction, which 
includes all pickups and large SUVs and some small and midsize SUVs. 
Another example is cylinder deactivation being limited to vehicles with 
6- or 8-cylinder engines. To simplify the analysis, NHTSA assumed that 
each class of vehicles would typically have vehicle construction and 
engines with a specific number of cylinders that is most representative 
of that vehicle class.
    Although we looked at ten vehicle classes separately, for some 
technologies the estimated incremental fuel consumption benefit and 
incremental cost were the same across all vehicle classes (as for 
engine accessory improvement), while for other technologies the 
estimated incremental fuel consumption benefit and incremental cost 
differed across classes (as for hybrid drivetrains). The main 
difference was with which path(s) each technology was expected to be 
associated.
    The exact cost and benefit of a given technology depends on 
specific vehicle characteristics (size, weight, base engine, etc.) and 
the existence of additional technologies that were already applied to 
the vehicle. In the section below, ranges of incremental cost and fuel 
consumption reduction values are listed where the values depend on 
vehicle characteristics and are independent of the order in which they 
are applied to a vehicle. All costs, which are reflective of estimated 
retail price equivalents (RPEs) were inflated by the producer price 
index (if needed) and are presented in year 2006 dollars, because this 
is the last year for which final economic indexing is available. Some 
cost estimates are based on supplier costs. In those instances, 
multipliers were included in those costs so that they would be treated 
in the same manner as cost estimates that are based on manufacturer 
costs. These incremental values were calculated by subtracting out all 
same-path synergies associated with a given technology and any 
preceding items on the same path. Essentially, the incremental percent 
reduction in fuel consumption and cost impacts represent improvements 
beyond the ones realized due to technologies already applied to the 
vehicle. As an example, a 5-speed automatic transmission could 
incrementally reduce fuel consumption by 2 to 3 percent at an 
incremental cost of $75 to $165 per vehicle, relative to a 4-speed 
automatic transmission. In turn, a 6-speed automatic transmission could 
incrementally reduce fuel consumption by 4.5 to 6.5 percent at an 
incremental cost of $10 to $20 per vehicle, relative to a 5-speed 
transmission.
    NHTSA acknowledges that this approach is different from the one it 
followed in establishing the reformed light truck standards for MYs 
2008-2011, where we relied nearly exclusively on the 2002 NAS report's 
estimates. Our preference remains to rely upon peer-review and credible 
studies, such as the 2002 NAS report; however we believe that the 
estimates made by the joint EPA/NHTSA team are accurate and defensible. 
The agency seeks comments on our assumptions and the cost, 
effectiveness and availability estimates provided. NHTSA also seeks 
comments on whether the order in which these technologies was applied 
by the Volpe model is proper and whether we have accurately accounted 
for technologies already included on vehicles and whether we have 
accurately accounted for technologies that are projected to be applied 
to vehicles. The agency also seeks comments on the ``synergy'' factors 
(discussed below) it has applied in order to adjust the estimated 
incremental effectiveness of some pairs of technology and on whether 
similar adjustments to the estimated incremental cost of some 
technologies should be made. In preparation for a final rule, NHTSA 
intends to update its technology-related methodologies and estimates, 
and expects that these anticipated updates will affect the form and 
stringency of the final standards.
a. Engine Technologies

Low-Friction Lubricants

    The use of lower viscosity engine and transmission lubricants can 
reduce fuel consumption. More advanced multi-viscosity engine and 
transmission oils are now available with improved performance in a 
wider temperature band, with better lubricating properties. However, 
even without any changes to fuel economy standards, most MY 2011-2015 
vehicles are likely to use 5W-30 motor oil, and some will use even less 
viscous oils, such as 5W-20 or possibly even 0W-20 to reduce cold start 
friction. This may directionally benefit the fuel economy improvements 
of valvetrain technologies such as cylinder deactivation, which rely on 
a minimum oil temperature (viscosity) for operation. Most manufacturers 
therefore attributed smaller potential fuel economy reductions and cost 
increases to lubricant improvements.
    The NAS Report estimated that low-friction lubricants could 
incrementally reduce fuel consumption by 1 percent at an incremental 
cost of $8 to $11.\60\ The NESCCAF study projected that low-friction 
lubricants could incrementally reduce fuel consumption by 1 percent at 
an incremental cost of $5 to $15; while the EEA report projected that 
low-friction lubricants could incrementally reduce fuel consumption by 
1 percent at an incremental cost of $10 to $20. In contrast, 
manufacturer data projected an estimated fuel consumption potential of 
0 percent to 1 percent at an incremental cost that ranged from $1 to 
$11, with many of them stating the costs as ranging from $1 to $5. 
NHTSA believes that these manufacturer estimates are more accurate and 
estimates that low-friction lubricants could reduce fuel consumption by 
0.5 percent for all vehicle types at an incremental cost of $3, which 
represents the mid-point of $2.50, rounded up to the next dollar.
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    \60\ The price increases noted in this chapter are slightly 
higher than shown in the NAS study, since they have been converted 
into calendar year 2006 prices.
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Reduction of Engine Friction Losses

    All reciprocating and rotating components in the engine are 
candidates for friction reduction, and minute improvements in several

[[Page 24368]]

components can add to a measurable fuel economy improvement. The amount 
of energy an engine loses to friction can be reduced in a variety of 
ways. Improvements in the design of engine components and subsystems 
will result in friction reduction, improved engine operation, greater 
fuel economy and reduced emissions. Examples include low-tension piston 
rings, roller cam followers, crankshaft design, improved material 
coatings, material substitution, more optimal thermal management, 
piston surface treatments, and as lubricant friction reduction. 
Additionally, as computer-aided modeling software continues to improve, 
more opportunities for incremental friction reduction might become 
apparent. Even without any changes to fuel economy standards, most MY 
2010-2015 vehicles are likely to employ one or more such techniques to 
reduce engine friction and other mechanical and hydrodynamic losses.
    The NAS Report estimated that such technologies could incrementally 
reduce fuel consumption by 1 to 5 percent at an incremental cost of $36 
to $146. NESCCAF predicted that such technologies could incrementally 
reduce fuel consumption by 0.5 percent at an incremental cost of $5 to 
$15; while the EEA report predicted that such technologies could reduce 
fuel consumption at an incremental cost of $10 to $55. Confidential 
manufacturer data indicates that engine friction reduction could 
incrementally reduce fuel consumption by 1 to 3 percent at an 
incremental cost of $0 to $168. Based on available information from 
these reports and confidential manufacturer data, NHTSA estimates that 
friction reduction could reduce fuel consumption for all vehicles by 1 
to 3 percent at a cost of $21 per cylinder. Thus, the incremental cost 
of engine friction reduction for a 4-cylinder engine is $0 to $84 
(applicable to subcompact and compact cars); for a 6-cylinder engine is 
$0 to $126 (applicable to midsize cars, large cars, small pickups, 
small SUVs, minivans and midsize SUVs); and for an 8-cylinder engine is 
$0 to $168 (applicable to large pickups and SUVs).

Multi-Valve Overhead Camshaft Engine

    It appears likely that many vehicles would still use overhead valve 
(OHV) engines with pushrods and one intake and one exhaust valve per 
cylinder during the early part of the next decade. Engines with 
overhead cams (OHC) and more than two valves per cylinder achieve 
increased airflow at high engine speeds and reductions of the valve 
train's moving mass and enable central positioning of spark plugs. Such 
engines, which are already used in some light trucks, typically develop 
higher power at high engine speeds. The NAS Report projected that 
multi-valve OHC engines could incrementally reduce fuel consumption by 
2 percent to 5 percent at an incremental cost of $109 to $146, and 
NHTSA found no sources to update these projections.
    For purposes of this rule, OHV engines and OHC engines were 
considered separately, and the model was generally not allowed to apply 
multivalve OHC technology to OHV engines, except where continuous 
variable valve timing and lift (CVVL) is applied to OHV engines. In 
that case, the model assumes conversion to DOHC valvetrain, because 
DOHC valvetrains are prerequisites for the application of any advanced 
engine technology over and above CVVL. Since applying CVVL to an OHV is 
the last improvement that could be made to such an engine, it's logical 
to assume that manufacturers would redesign that engine as a DOHC and 
include CVVL as part of that redesign.
    For 4-cylinder engines we estimated that the cost to redesign an 
OHV engine as a DOHC that includes CVVL would be $599 ($169 for 
conversion to DVVL, $254 for conversion to CVVL, and $176 for 
conversion to DOHC, which comprises an additional camshaft and valves), 
with estimated fuel consumption reduction of 2 to 3 percent. For 6-
cylinder engines we estimated that the cost to redesign an OHV engine 
as a DOHC that includes CVVL would be $1262 ($246 for conversion to 
DVVL, $488 for conversion to CVVL, and $550 for conversion to DOHC, 
which comprises an additional camshaft and valves), with estimated fuel 
consumption reduction of 1 to 4 percent. For 8-cylinder engines we 
estimated that the cost to redesign an OHV engine as a DOHC that 
includes CVVL would be $1380 ($322 for conversion to DVVL, $508 for 
conversion to CVVL, and $550 for conversion to DOHC, which comprises an 
additional camshaft and valves), with estimated fuel consumption 
reduction of 2 to 3 percent. Incremental cost estimates for DVVL and 
CVVL are discussed below.
    NHTSA believes that the NESCCAF report and confidential 
manufacturer data are more accurate, and thereby estimates that a 
conversion of an OHV engine to a DOHC engine with CVVL could 
incrementally reduce fuel consumption by 1 to 4 percent at an 
incremental cost of $599 to $1,380 compared to an OHV with VVT.

Cylinder Deactivation

    For the vast majority of vehicles, each cylinder is always active 
while the engine is running. Under partial load conditions, the 
engine's specific fuel consumption could be reduced if some cylinders 
could be disabled, such that the active cylinders operate at higher 
load. In cylinder deactivation, some (usually half) of the cylinders 
are ``shut down'' during light load operation--the valves are kept 
closed, and no fuel is injected--as a result, the trapped air within 
the deactivated cylinders is simply compressed and expanded as an air 
spring, with minimal friction and heat losses. The active cylinders 
combust at almost double the load required if all of the cylinders were 
operating. Pumping losses are significantly reduced as long as the 
e