[Federal Register Volume 77, Number 165 (Friday, August 24, 2012)]
[Rules and Regulations]
[Pages 51649-51680]
[FR Doc No: 2012-20480]

Vol. 77

Friday,

No. 165

August 24, 2012

Part III

Department of Transportation

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National Highway Traffic Safety Administration

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49 CFR Part 571

Federal Motor Vehicle Safety Standards; Motorcycle Brake Systems; Final
Rule

Federal Register / Vol. 77, No. 165 / Friday, August 24, 2012 / Rules
and Regulations

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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Part 571

[Docket No. NHTSA-2012-0123]
RIN 2127-AK16

Federal Motor Vehicle Safety Standards; Motorcycle Brake Systems

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

ACTION: Final rule.

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SUMMARY: This final rule amends the Federal motor vehicle safety
standard (FMVSS) on motorcycle brake systems to add and update
requirements and test procedures and to harmonize with a global
technical regulation (GTR) for motorcycle brakes. The GTR was developed
under the United Nations 1998 Global Agreement with the U.S. as an
active participant, and it was derived from various motorcycle braking
regulations from around the world, including the U.S. motorcycle brake
systems standard. This final rule includes numerous modifications to
the test procedures for motorcycle brake systems, but does not change
the scope, applicability, and safety purpose of the motorcycle brake
systems FMVSS.

DATES: This final rule is effective October 23, 2012. Petitions for
reconsideration must be received by October 9, 2012.
    The various compliance dates for these regulations are set forth,
as applicable, in Sec.  571.122, S3. Optional early compliance is
permitted on and after October 23, 2012.
    The incorporation by reference of certain publications listed in
this rule is approved by the Director of the Federal Register as of
October 23, 2012.

ADDRESSES: Petitions for reconsideration must be submitted to:
Administrator, National Highway Traffic Safety Administration, 1200 New
Jersey Avenue SE., Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT:
    For technical issues: Mr. George Soodoo, Division Chief, Vehicle
Dynamics (NVS-122), Office of Crash Avoidance Standards (Email:
<EMAIL_ADDRESS>(Telephone:<PHONE_NUMBER>) (Fax: (202) 366-
5930) or Mr. Ezana Wondimneh, Division Chief, International Policy and
Harmonization (NVS-133), Office of International Policy, Fuel Economy
and Consumer Programs (Email<EMAIL_ADDRESS>(Telephone:
(202) 366-0846) (Fax:<PHONE_NUMBER>).
    For legal issues: Mr. David Jasinski, Office of the Chief Counsel
(NCC-112) (Email<EMAIL_ADDRESS>(Telephone:<PHONE_NUMBER>)
(Fax:<PHONE_NUMBER>).
    You may send mail to these officials at National Highway Traffic
Safety Administration, 1200 New Jersey Avenue SE., Washington, DC
20590.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Executive Summary
II. Background
    A. Current Requirements of FMVSS No. 122
    B. Harmonization Efforts
    C. Comments Received in Response to the Notice of Proposed
Rulemaking
III. General Improvements to FMVSS No. 122
    A. New Terminology
    B. Measurement of Performance Using Stopping Distance
    C. Motorcycle Test Speed and Corrected Stopping Distance
    D. Peak Braking Coefficient
    E. Test Sequence
    F. Brake Application Force Measurement
    G. Brake Temperature Measurement
    H. Burnishing Procedure
    I. Notice of Wear
IV. Specific Performance Test Improvements to FMVSS No. 122
    A. Dry Stop Test--Single Brake Control Actuated
    B. Dry Stop Test--All Service Brake Controls Actuated
    C. High-Speed Test
    D. Wet Brake Test
    E. Heat Fade Test
    F. Parking Brake System Test
    G. Antilock Brake System (ABS) Performance Test
    1. Low Friction Surface for ABS Testing
    2. Wheel Lock
    3. Tests With ABS Electrical Failure
    4. Other ABS-Related Comments
    H. Partial Failure Test--Split Service Brake System
    I. Power-Assisted Braking System Failure Test
V. Other Comments and Technical Amendments
    A. Labeling Requirements
    B. Versions of ASTM Standards
    C. Terminology
VI. Compliance Date
VII. Costs and Benefits
VIII. Regulatory Analyses and Notices

I. Executive Summary

    Currently, motorcycles must comply with a series of performance
requirements established in Federal Motor Vehicle Safety Standard
(FMVSS) No. 122, Motorcycle Brake Systems, in the early 1970's. While
the current motorcycle brake performance requirements have ensured a
minimum level of braking performance, they have not kept pace with the
advancement of modern technologies. The National Highway Traffic Safety
Administration (NHTSA) seeks to keep its standards up to date. This
final rule updates FMVSS No. 122 based on the Motorcycle Brake Systems
Global Technical Regulation (GTR), which reflects the capabilities of
current in-use technologies. Updating the standard to reflect modern
technologies would help prevent the introduction of unsafe motorcycle
brake systems on the road. Moreover, benefits from harmonization,
including decreased testing costs and ease of market entry, would
accrue to current and new manufacturers, and would in turn get passed
on to consumers.
    The substantive performance tests and requirements of FMVSS No. 122
have not been updated since their adoption in 1972. Since that time,
motorcycle brake system technology has significantly changed and
improved such that FMVSS No. 122 no longer reflects the current
performance of motorcycle brake system technologies. In order to
address modern braking technologies, the agency sought to improve the
requirements and test procedures of FMVSS No. 122. These efforts
coincided with the 2002 adoption of the initial Program of Work under
the 1998 United Nations' Economic Commission for Europe (UNECE)
Agreement Concerning the Establishment of Global and Technical
Regulations for Wheeled Vehicles, Equipment and Parts Which Can Be
Fitted And/or Be Used On Wheeled Vehicles (1998 Agreement).\1\ That
program included motorcycle brake systems as one of the promising areas
for the establishment of a GTR. The agency sought to work
collaboratively on modernizing motorcycle brake regulations with other
Contracting Parties to the 1998 Agreement (Contracting Parties),
particularly Canada, the European Union and Japan. Through the exchange
of information on ongoing research and testing and through the
leveraging of resources for testing and evaluations, the agency
participated in successful efforts that culminated in the establishment
of the Motorcycle Brake Systems GTR under

the 1998 Agreement. We believe that the provisions of the GTR NHTSA is
adopting in today's final rule will improve the current requirements
and test procedures of FMVSS No. 122 by updating them to more closely
reflect the capabilities of modern technologies that are already being
used in most motorcycles sold in the U.S.
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    \1\ The 1998 UNECE Agreement Concerning the Establishment of
Global and Technical Regulations for Wheeled Vehicles, Equipment and
Parts Which Can Be Fitted And/or Be Used On Wheeled Vehicles (1998
Agreement) was concluded under the auspices of the United Nations
and provides for the establishment of globally harmonized vehicle
regulations. This 1998 Agreement, whose conclusion was spearheaded
by the United States, entered into force in 2000 and is administered
by the UNECE's World Forum for the Harmonization of Vehicle
Regulations (WP.29). See http://www.unece.org/trans/main/wp29/wp29wgs/wp29gen/wp29age.html (last accessed September 28, 2011).
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    This final rule makes improvements to FMVSS No. 122, but retains
many fundamental elements of the current standard. For example, this
final rule adopts new terminology and includes definitions for terms
used in the regulatory text, including adopting five categories for
motorcycles based on the number of wheels and maximum speed of the
motorcycle. This final rule retains stopping distance as the sole
compliance criterion for several performance tests in FMVSS No. 122.
The current FMVSS No. 122 is improved by specifying a tolerance for the
initial test speed for compliance tests, recognizing that even
professional test drivers cannot attain the exact speed specified in
every test. This final rule incorporates by reference an ASTM
International method for the measurement of the coefficient of friction
of the test surface that is already used in NHTSA's other brake
standards. This final rule, like the existing version of FMVSS No. 122,
specifies the order in which NHTSA will conduct its compliance tests,
but it moves the brake fade test to the end of the test sequence in
order to eliminate a re-burnishing procedure, resulting in a more
efficient test sequence. The procedure for the initial burnish is
retained with minor alteration.
    The rule includes several tests that would enhance the safe
operation of a motorcycle: Tests both at gross vehicle weight rating
(GVWR) and lightly loaded vehicle weight, which ensure adequate braking
performance at the two extremes of the loading conditions; a wet brake
test that is more representative of the manner in which brakes are
wetted during real world riding in wet conditions; a variety of ABS
performance tests to ensure that motorcycles equipped with ABS have
adequate antilock performance during emergency braking or on slippery
road conditions; and a new requirement that addresses failure in the
power-assisted braking system.
    Specifically, the rule will improve the FMVSS No. 122 requirements
in several areas. First, it will make the dry brake test requirement
more stringent by specifying testing of each service brake control
individually, with the motorcycle in the fully loaded condition.
Second, the rule will implement a more stringent high speed test
requirement by specifying a slightly higher rate of deceleration.
Third, the rule replaces the existing wet brake test with one that
better simulates actual in-service conditions, by spraying water onto
the brake disc, instead of submerging the brake system before testing.
Fourth, the rule specifies an improved heat fade test procedure based
on European and Japanese national regulations, which share the same
test procedure and performance requirements. Fifth, the rule specifies
performance requirements for antilock brake systems (ABS), if present.
Until now, FMVSS No. 122 did not contain performance criteria for ABS,
where present on motorcycles.\2\ Finally, the rule contains a new test
requirement to evaluate the motorcycle's performance in the event of a
failure in the power-assisted braking system, if so equipped.
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    \2\ Note, though, that we are not mandating in this rule that
motorcycles be equipped with ABS brakes.
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    This final rule responds to public comments on the notice of
proposed rulemaking \3\ (NPRM) and adopts the requirements, test
procedures, and performance criteria of the NPRM without significant
deviations from the proposal.
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    \3\ See Federal Motor Vehicle Safety Standards, Motorcycle Brake
Systems, Notice of Proposed Rulemaking, 73 FR 54020 (Sept. 17, 2008)
(hereinafter ``FMVSS No. 122 NPRM'').
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    Notably, we have retained labeling requirements for brake systems
components that were in FMVSS No. 122, but were not in the GTR. NHTSA
feels strongly that those required labels identify important safety
features and safety-related information, and they have longstanding
applicability in FMVSS No. 122. The parties involved in developing the
GTR understood that national regulations would continue to apply
labeling and warning requirements of this sort when each national
regulatory body adopted the provisions of the GTR. Since the vast
majority of benefits from harmonization are achieved because of the
harmonization of test procedures and performance criteria, the
retention of unique FMVSS No. 122 labeling requirements does not reduce
the benefits of international harmonization.
    Besides updating requirements and test procedures to help ensure
the safety of motorcycle brake systems, today's final rule also
provides benefits from harmonization. Motorcycle manufacturers, and
ultimately, consumers, both here and abroad, can expect to achieve cost
savings through the formal harmonization of differing sets of standards
when the Contracting Parties implement the new GTR. Motorcycles are
vehicles that are prepared for the world market. It will be more
economically efficient to have manufacturers using the same test
procedures and meeting the same performance requirements worldwide.
This rule will help achieve these benefits and thus reduce the amount
of resources utilized to test motorcycles.
    Although this final rule adds and updates FMVSS No. 122 performance
requirements and provides benefits from harmonization, we anticipate
that virtually all motorcycles currently sold in the U.S. can meet the
requirements, without the need for any changes to their brake systems.
Thus, we are not able to quantify direct safety benefits from this
final rule.
    We have considered whether this final rule will impose additional
costs on manufacturers, including costs associated with certifying
motorcycles as compliant with these new tests. We expect that a limited
number (approximately 8,000) of three-wheeled motorcycles will require
upgraded brake systems at a cost of $13.38 per motorcycle. As a result,
the total cost motorcycle manufacturers will incur as a result of
today's final rule is approximately $107,040 per year. All costs that
manufacturers may incur if they choose to certify compliance based on
NHTSA's test procedures will be offset by cost savings from the
elimination of test procedures under the current version of FMVSS No.
122. For those manufacturers that choose to certify compliance by
following NHTSA's test procedures, we anticipate that this final rule
would result in a cost savings of less than one-tenth of a cent per
motorcycle.
    While the agency has not been able to quantify safety benefits for
this rule since virtually all motorcycles sold in the U.S. can
currently meet the proposed requirements, the agency is considering
taking several other actions to attempt to decrease motorcycle
fatalities.\4\ Given the sources and magnitude of the safety problem
posed by increased motorcycle fatalities, the Department of
Transportation intends to address motorcycle safety

comprehensively, focusing on regulatory, as well as behavioral and
roadway, countermeasures and strategies. In October 2007, the
Department announced the ``Action Plan to Reduce Motorcycle
Fatalities,'' which will help reduce motorcycle fatalities with new
national safety and training standards, a curb on the use of
counterfeit labeling on helmets, a new focus on motorcycle-specific
road improvements, training for law enforcement officers on how to spot
unsafe motorcyclists, and a broad public awareness campaign on rider
safety.\5\
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    \4\ See U.S. Department of Transportation, ``Action Plan to
Reduce Motorcycle Fatalities,'' (October 2007), available at http://www.nhtsa.gov/DOT/NHTSA/Communication%20&%20Consumer%20Information/Articles/Associated%20Files/4640-report2.pdf (last accessed April
10, 2012) (hereinafter ``Action Plan to Reduce Motorcycle
Fatalities''); National Highway Traffic Safety Administration
(NHTSA) & Motorcycle Safety Foundation (MSF), ``National Agenda for
Motorcycle Safety,'' available at http://www.nhtsa.gov/people/injury/pedbimot/motorcycle/00-NHT-212-motorcycle/index.html (last
accessed April 10, 2012); see generally http://www.nhtsa.gov/Safety/Motorcycles (last accessed April 10,2012).
    \5\ Id. at 1.
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II. Background

    FMVSS No. 122, Motorcycle brake systems, 49 CFR 571.122, took
effect on January 1, 1974.\6\ FMVSS No. 122 specifies performance
requirements for motorcycle brake systems. The purpose of the standard
is to provide safe motorcycle brake performance under normal and
emergency conditions. The safety afforded by a motorcycle's braking
system is determined by several factors, including stopping distance,
linear stability while stopping, fade resistance, and fade recovery. A
safe system should have features that both guard against malfunction
and stop the motorcycle if a malfunction should occur in the normal
service system. FMVSS No. 122 was originally conceived to cover each of
these aspects of brake safety by specifying equipment and performance
requirements appropriate for both two-wheeled and three-wheeled
motorcycles. Because motorcycles differ significantly in configuration
from other motor vehicles, the agency established a separate brake
standard applicable only to this vehicle category. Many of the FMVSS
No. 122 test procedures are, however, similar to those for passenger
cars.\7\
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    \6\ Response to Petitions for Reconsideration, Motorcycle Brake
Systems, 37 FR 11973 (June 16, 1972).
    \7\ See Brake Systems on Motorcycles Proposed Motor Vehicle
Safety Standard, 36 FR 5516 (Mar. 24, 1971).
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    Only a few changes have been made to the regulation since it was
established. In response to petitions, a 1974 final rule changed the
application of FMVSS No. 122 requirements for low-speed motor-driven
cycles (motorcycles with 5-brake horsepower or less whose speed
attainable in one mile is 30 miles per hour or less).\8\ In 1978, NHTSA
amended the FMVSS No. 122 parking brake test to clarify the test
conditions and incorporate an interpretation applicable to three-
wheeled motorcycles.\9\ In 2001, the minimum hand lever force
requirements for the heat fade test and water recovery test were
decreased to facilitate the manufacture of motorcycles with combined
braking systems.\10\ Except for the above changes, FMVSS No. 122 has
not been amended to keep pace with the advancement of modern brake
technologies.
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    \8\ Final Rule, Motor-Driven Cycles, 39 FR 32914 (Sept. 12,
1974).
    \9\ Final Rule, Motorcycle Brake Systems, 43 FR 46547 (Oct. 10,
1978).
    \10\ Final Rule, Federal Motor Vehicle Safety Standards,
Motorcycle Brake Systems, 66 FR 42613 (Aug. 14, 2001).
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A. Current Requirements of FMVSS No. 122

    FMVSS No. 122 applies to both two-wheeled and three-wheeled
motorcycles. Among other requirements, the motorcycle manufacturer must
ensure that each motorcycle can meet performance requirements under
conditions specified in paragraph S6, Test conditions, and as specified
in paragraph S7, Test procedures. The tests in S7 include pre- and
post-burnishment effectiveness tests, a fade and recovery test, a
partial failure test, a water recovery test, and parking brake test. At
the end of the test procedure sequence, the brake system must pass a
durability inspection. All stops must be made without lockup of any
wheel.
    Equipment. Each motorcycle is required to have either a split
service brake system or two independently actuated brake systems. The
former system encompasses a service brake system combined with a hand
operated parking brake system for three-wheeled motorcycles. If a
motorcycle has a hydraulic service brake system, it must also have a
reservoir for each brake circuit, and a master cylinder reservoir label
advising the proper grade of brake fluid. If the service brake system
is a split hydraulic type, a failure indicator lamp is required.
Additionally, three-wheeled motorcycles must be equipped with a
friction type parking brake with a solely mechanical means to retain
engagement. The service brake system must be installed so that the
lining thickness of the drum brake shoes may be visually inspected,
either directly or by using a mirror without removing the drums, and so
that disc brake friction lining thickness may be visually inspected
without removing the pads.
    Pre- and post-burnish tests. The service brake system and each
independently actuated service brake system on each motorcycle must be
capable of stopping within specified distances from 30 miles per hour
(mph) and 60 mph. The brakes are then burnished by making 200 stops
from 30 mph at 12 feet per second per second (fps\2\). The service
brake system must then be capable of stopping at specified distances
from 80 mph and from a speed divisible by 5 mph that is 4 mph to 8 mph
less than the maximum motorcycle speed. The post-burnish tests are
conducted in the same way as the pre-burnish stops, and the service
brakes must be capable of stopping the motorcycle within the post-
burnish specified stopping distances.
    Fade and recovery test. The fade and recovery test compares the
braking performance of the motorcycle before and after ten 60-mph stops
at a deceleration of not less than 15 fps\2\. As a check test, three
baseline stops \11\ are conducted from 30 mph at 10 to 11 fps\2\, with
the maximum brake lever and maximum pedal forces recorded during each
stop, and averaged over the three baseline stops. Ten 60-mph stops are
then conducted at a deceleration rate of not less than 15 fps\2\,
followed immediately by five fade recovery stops from 30 mph at a
deceleration rate of 10 to 11 fps\2\. The maximum brake pedal and lever
forces measured during the fifth recovery stop must be within plus 20
pounds and minus 10 pounds of the baseline average maximum brake pedal
and lever forces.
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    \11\ The baseline check is used to establish a specific
motorcycle's pre-test performance to provide a basis for comparison
with post-test performance. This comparison is intended to ensure
adequate brake performance, at reasonable lever and pedal forces,
after numerous high speed or wet brake stops.
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    Partial failure test. In the event of a pressure component leakage
failure, the remaining portion of the service brake system must
continue to operate and shall be capable of stopping the motorcycle
from 30 mph and 60 mph within specified stopping distances. The brake
failure indicator light must activate when the master cylinder fluid
level decreases below the minimum specified level.
    Water recovery test. The water recovery test compares the braking
performance of the motorcycle before and after the motorcycle brakes
are immersed in water for two minutes. Three baseline stops are
conducted from 30 mph at 10 to 11 fps\2\, with the maximum brake lever
and pedal forces recorded during each stop, and averaged over the three
baseline stops. The motorcycle brakes are then immersed in water for
two minutes, followed immediately by five water recovery stops from 30
mph at a deceleration rate of 10 to 11 fps\2\. The maximum brake pedal
and lever forces measured during the fifth recovery stop must be within

plus 20 pounds and minus 10 pounds of the baseline average maximum
brake pedal force and the lever force.
    Parking brake test. For motorcycles required to be equipped with a
parking brake system, such system must be able to hold the motorcycle
on a 30 percent grade, in both forward and reverse directions, for 5
minutes. A parking brake indicator lamp must be provided.

B. Harmonization Efforts

    Globally, there are several existing regulations, directives, and
standards that pertain to motorcycle brake systems. As all share
similarities, the Contracting Parties to the 1998 Agreement under WP.29
tentatively determined that the development of a GTR under the 1998
Agreement would be beneficial.
    In an effort to select the best of existing performance
requirements for a GTR, the U.S. and Canada conducted analyses of the
relative stringency of three national motorcycle brake system
regulations. These were the UNECE Regulation No. 78, FMVSS No. 122, and
the Japanese Safety Standard JSS 12-61. The subsequent reports, along
with proposed provisions of a GTR, were presented at meetings of the
Working Party for Brakes and Running Gear (GRRF),\12\ and were made
available in the NPRM docket.\13\ While using different methodologies,
the results from the U.S./Canada report were similar to an industry led
report that examined the issue under the GRRF.\14\ These studies
completed by the U.S., Canada, and the industry provided the basis for
the development of the technical requirements of the GTR.
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    \12\ The GRRF is made up of delegates from many countries around
the world, and who have voting privileges. Representatives from
manufacturing and consumer groups also attend and participate in the
GRRF and informal working groups that are developing GTRs. Those
that chose not to participate are kept apprised of the GTR progress
from progress reports which are presented at the GRRF meetings and
then posted on the UN's Web site.
    \13\  See Docket Nos. NHTSA-2008-0150-0005.1, NHTSA-2008-0150-
0006.1.
    \14\  See Docket No. NHTSA-2008-0150-0007.1.
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    The informal group used the feedback from the GRRF presentations to
assist with the completion of the proposed GTR, a copy of which can be
found in the NPRM docket.\15\ Where national regulations or standards
address the same subject, e.g. dry stop or heat fade performance
requirements, the informal group reviewed comparative data on the
relative stringency of the requirements from the research and studies
and included the most stringent options. Additional testing was
conducted to confirm or refine the testing and performance
requirements. Qualitative issues, such as which wet brake test to
include, were discussed on the basis of the original rationales and the
appropriateness of the tests to modern conditions and technologies. In
each of these steps, specific technical issues were raised, discussed,
and resolved, as discussed in the NPRM and below. The informal working
group held a total of eight meetings concerning the development of the
GTR. In November 2006, WP.29 approved the GTR on Motorcycle Brake
Systems, and established it in the Global Registry as Global Technical
Regulation No. 3.
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    \15\ See Docket No. NHTSA-2008-0150-0002.1. The first formal
proposal for a GTR concerning motorcycle brake systems was presented
during the 58th GRRF session in September 2005. A more detailed
report on the technical details, deliberations and conclusions,
which led to the proposed GTR, was provided separately as informal
document No. GRRF-58-16. See Docket No. NHTSA-2008-0150-0004.1.
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    As explained in the NPRM, the GTR on motorcycle brake systems
consists of a compilation of the most stringent and relevant test
procedures and performance requirements from current standards and
regulations. As a result of the comparison process, the selected
performance requirements of the GTR are mainly drawn from the UNECE
Regulation No. 78, the FMVSS No. 122 and the Japanese Safety Standard
JSS 12-61 (JSS 12-61). The GTR is comprised of several fundamental
tests, each with their respective test procedures and performance
requirements. These tests and procedures are listed below along with
the national regulation on which they are based:

 Burnish procedure (FMVSS No. 122)
 Dry stop test with each service brake control actuated
separately (UNECE Regulation No. 78/JSS 12-61)
 Dry stop test with all service brake systems applied
simultaneously (FMVSS No. 122)
 High speed test (JSS 12-61)
 Wet brake test (UNECE Regulation No. 78/JSS 12-61)
 Heat fade test (UNECE Regulation No. 78/JSS 12-61)
 Parking brake test (UNECE Regulation No. 78/JSS 12-61)
 ABS tests (UNECE Regulation No. 78/JSS 12-61)
 Partial failure test--split service brake systems (FMVSS No.
122)
 Power-assisted braking system failure test (new)

    The GTR process was transparent to country delegates, industry
representatives, public interest groups, and other interested parties.
Information regarding the meetings and negotiations was publicly
available through notices published periodically by the agency and UN
Web site.\16\ See the NPRM for additional discussion of the
harmonization process.\17\
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    \16\ See Recommendations for Establishing Global Technical
Regulations Under the United Nations/Economic Commission for Europe
1998 Global Agreement, Motor Vehicle Safety, 66 FR 4893, Docket No.
NHTSA-00-7538 (Jan. 18, 2001); NHTSA's Activities Under the United
Nations Economic Commission for Europe 1998 Global Agreement, 69 FR
60460, Docket No. NHTSA-03-14395 (Oct. 8, 2004); NHTSA's Activities
Under the United Nations Economic Commission for Europe 1998 Global
Agreement, 71 FR 59582, Docket No. NHTSA-2003-14395 (Oct. 10, 2006);
see also http://www.unece.org/trans/main/wp29/wp29wgs/wp29grrf/grrf-infmotobrake7.html for a record of all GRRF meetings and documents
presented therein (last accessed April 26, 2010).
    \17\ FMVSS No. 122 NPRM, 73 FR at 54022.
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C. Comments Received in Response to the Notice of Proposed Rulemaking

    The U.S., as a Contracting Party of the 1998 Agreement that voted
in favor of establishing this GTR at the November 15, 2006 Session of
the Executive Committee of the 1998 Agreement, is obligated under the
1998 Agreement to initiate the process for adopting the provisions of
the GTR.\18\ On September 17, 2008, NHTSA published a notice of
proposed rulemaking (NPRM) to update FMVSS No. 122 that was based on
the Motorcycle Brake Systems GTR, which satisfied the U.S. obligations
under the 1998 Agreement noted above.
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    \18\ While the 1998 Agreement obligates such Contracting Parties
to initiate rulemaking within one year of the establishment of the
GTR, it leaves the ultimate decision of whether to adopt the GTR
into their domestic law to the parties themselves.
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    In response to the NPRM, NHTSA received comments from the following
parties: The Motorcycle Industry Council (MIC),\19\ American Honda
Motor Company, Inc. (Honda),\20\ Harley-Davidson Motor Company (Harley-
Davidson),\21\ Robert Bosch LLC (Bosch),\22\ the Insurance Institute
for Highway Safety (IIHS),\23\ ASTM International (ASTM),\24\ SMO
Group, L.L.C. (SMO),\25\ and the American Association for Justice
(AAJ).\26\
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    \19\ Motorcycle Industry Council Inc. Comments, Docket No.
NHTSA-2008-0150-0017.1 (hereinafter ``MIC Comments'').
    \20\ American Honda Motor Co., Inc. Comments, Docket No. NHTSA-
2008-0150-0018.1 (hereinafter ``Honda Comments'').
    \21\ Harley-Davidson Motor Company, Docket No. NHTSA-2008-0150-
0012 (hereinafter ``Harley-Davidson Comments'').
    \22\ Robert Bosch LLC Comments, Docket No. NHTSA-2008-0150-
0016.1 (hereinafter ``Robert Bosch Comments'').
    \23\ Insurance Institute for Highway Safety Comments, Docket No.
NHTSA-2008-0150-0015.1.
    \24\ ASTM International Comments, Docket No. NHTSA-2008-0150-
0011.1.
    \25\ SMO Group, L.L.C. Comments, Docket No. NHTSA-2008-0150-
0013.1.
    \26\ American Association for Justice Comments, Docket No.
NHTSA-2008-0150-0014.1.

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    All comments received were timely, and they are each considered in
this final rule and discussed below, with one exception. The AAJ
commented on the language of the preamble concerning implied
preemption, and its comment was neither related to the proposed
regulatory text, nor to motorcycle braking nor to motorcycle
safety.\27\ Because that comment did not specifically relate to the
proposal, and because NHTSA has already responded to a similar AAJ
comment in the context of another Federal Register notice,\28\ we do
not address the AAJ comment any further here.
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    \27\ The AAJ has submitted to several other rulemaking dockets
similar comments regarding the agency's preamble discussions of
preemption.
    \28\ See Federal Motor Vehicle Safety Standards; Electric-
Powered Vehicles; Electrolyte Spillage and Electrical Shock
Protection, 75 FR 33515, 33524-25 (Jun. 12, 2010).
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    Comments were generally supportive of NHTSA's intent to harmonize
FMVSS No. 122 with other nations' and regulatory bodies' standards
through the adoption of the GTR. The substantive comments received were
concerned mainly with test procedures rather than with brake system
design requirements. Specifically, Harley-Davidson, Honda, and the
Motorcycle Industry Council (MIC) all commented on each of the
following three issues, which were the main issues in their submittals:
     The NHTSA proposal in the NPRM specified stopping distance
as the sole compliance criterion for several performance tests in FMVSS
No. 122 while leaving out the option to use Mean Fully Developed
Deceleration (MFDD) where applicable. Commenters requested that NHTSA
include MFDD as an alternative compliance option for measuring stopping
performance.
     The NPRM specified that Peak Braking Coefficient (PBC) be
measured by an ASTM skid-trailer method only. It did not include other
methods that were stated in the GTR for measurement of test surface
friction coefficient. Commenters requested that the agency allow
manufacturers the option to choose which test method it uses to measure
PBC.
     The NHTSA proposal changed ``nominal PBC'' as it appears
in the GTR to just ``PBC,'' i.e., NHTSA removed the word ``nominal'' in
specifying the friction coefficient of test track surfaces used for
motorcycle brake testing. Commenters requested that NHTSA retain the
GTR term ``nominal,'' based on best engineering practices.

III. General Improvements to FMVSS No. 122

    Here, we discuss the proposed general amendments and improvements
to FMVSS No. 122, any comments received on these proposed improvements,
and the agency's response to those comments. Where no comments were
received on a proposed amendment, or a certain aspect of an amendment,
NHTSA has generally adopted those proposals in accordance with the
rationale detailed in the NPRM. Although this final rule states as such
for each amendment, we generally will not repeat the rationale and
justification for aspects of the proposal that did not receive comment.
We refer readers to the NPRM for the basis for those amendments.\29\
---------------------------------------------------------------------------

    \29\ See FMVSS No. 122 NPRM, 73 FR at 54023-54027.
---------------------------------------------------------------------------

A. New Terminology

    The NPRM proposed to revise or add definitions in FMVSS No. 122
(paragraph S4) where necessary to define terms used in the proposed
regulatory text, and we are largely retaining the definitions as
proposed in the NPRM. In order to streamline the proposed regulatory
text to more closely reflect the GTR text, some of the new proposed
terms were common terminology and definitions based on the UN document
titled ``Special Resolution No. 1 Concerning the Common Definitions of
Vehicle Categories, Masses and Dimensions (S.R.1)'' \30\ (UN Doc.
S.R.1) developed for the purposes of the GTRs. Thus, the NPRM proposed
to add certain new definitions to Sec.  571.122 S4, Definitions, that
may be similar to existing 49 CFR Part 571 definitions. For example,
current FMVSS No. 122 specifies that performance requirements must be
met when the ``motorcycle weight is unloaded vehicle weight plus 200
pounds.'' \31\ This is effectively equivalent to the mass term
``lightly loaded'' in the proposed rule, which is the testing condition
specified for the proposed dry stop test (all service brake controls
actuated), the high-speed test, the antilock brake systems tests, and
the partial failure test.\32\ These proposed terms, some of which may
be similar or equivalent to existing terms defined elsewhere in 49 CFR
Part 571, are used in the motorcycle brakes GTR in an effort to
streamline the GTR and maximize harmonization benefits.
---------------------------------------------------------------------------

    \30\ World Forum for Harmonization of Vehicle Regulations
(WP.29), Special Resolution No. 1 Concerning the Common Definitions
of Vehicle Categories, Masses and Dimensions (S.R.1), U.N. Doc.
TRANS/WP.29/1045 (Sept. 15, 2005), available at http://www.unece.org/trans/doc/2005/wp29/TRANS-WP29-1045e.pdf (last
accessed April 26, 2010).
    \31\ 49 CFR 571.122, S6.1. ``Unloaded vehicle weight'' is
defined under 49 CFR 571.3(b) to mean ``the weight of a vehicle with
maximum capacity of all fluids necessary for operation of the
vehicle, but without cargo, occupants, or accessories that are
ordinarily removed from the vehicle when they are not in use.''
    \32\ Lightly loaded means the sum of unladen vehicle mass (mass
of the vehicle with bodywork and all factory fitted equipment, and
fuel tanks filled to at least 90 percent) and driver mass ``plus 15
kg for test equipment, or the laden condition, whichever is less.''
FMVSS No. 122 S4, Definitions (proposed).
---------------------------------------------------------------------------

    Additionally, the proposed rule divided motorcycles into five
categories, which are referenced in the GTR. These motorcycle
categories are based on number of wheels and maximum speed, and were
originally defined in the UN Doc. S.R.1, as amended in May 2007.\33\ We
included these categories in the definitions portion of proposed FMVSS
No. 122 because under the GTR some performance tests do not apply to
certain motorcycle categories, and certain motorcycle categories have
different performance requirements than others.
---------------------------------------------------------------------------

    \33\ See WP.29, Amendment to Special Resolution No. 1 Concerning
the Common Definitions of Vehicle Categories, Masses, and
Dimensions, U.N. Doc. ECE/TRANS/WP.29/1045/Amend.1 (May 9, 2007),
available at http://www.unece.org/trans/main/wp29/wp29wgs/wp29gen/wp29fdoc/1000/ECE-TRANS-WP29-1045a1e.pdf (last accessed April 26,
2010).
---------------------------------------------------------------------------

    Category 3-1 and category 3-3 motorcycles are two-wheeled
motorcycles. Category 3-1 motorcycles are two-wheeled motorcycles with
an engine cylinder capacity not exceeding 50 cm\3\ and a maximum design
speed not exceeding 50 kilometers per hour (km/h). Category 3-3
motorcycles are two-wheeled motorcycles with an engine cylinder
capacity exceeding 50 cm\3\ or a maximum design speed exceeding 50 km/
h. Category 3-2 motorcycles are three-wheeled motorcycles of any wheel
arrangement with an engine cylinder capacity not exceeding 50 cm\3\ and
a maximum design speed not exceeding 50 km/h. Category 3-4 motorcycles
are those manufactured with three wheels asymmetrically arranged in
relation to the longitudinal median plane with an engine cylinder
capacity exceeding 50 cm\3\ or a maximum design speed exceeding 50 km/
h. Finally, category 3-5 motorcycles are motorcycles manufactured with
three wheels symmetrically arranged in relation to the longitudinal
median plane with an engine cylinder capacity exceeding 50 cm\3\ or a
maximum design speed exceeding 50 km/h.
    Motorcycle categories. Based on comments from both Harley-Davidson

and the MIC regarding inconsistencies between category 3-4 and category
3-5 requirements, NHTSA has identified a series of mistakes in the
proposed regulatory text relating to the identification of these two
categories. For example, Harley-Davidson and the MIC commented that the
stopping distances for category 3-4 and 3-5 motorcycles listed in Table
2 (Performance requirements, Dry stop test--single brake control
actuated) appear to have been incorrectly reversed in the first two
sections of the table: Single Brake System--Front Wheel(s) Braking
Only, and Single Brake System--Rear Wheel(s) Braking Only.\34\ Proposed
regulatory text Table 2 listed these tests as inapplicable to category
3-4 motorcycles and listed a stopping distance for category 3-5
motorcycles. These commenters noted that under the proposed regulatory
text, stopping distances would be inapplicable for category 3-5
vehicles in these two sections because those vehicles are required to
have a combined or split service brake. However, as noted by the
commenters, motorcycle-sidecar combinations of category 3-4 would still
be permitted to be equipped with separate brakes.
---------------------------------------------------------------------------

    \34\ Harley-Davidson Comments, Docket No. NHTSA-2008-0150-0012
at 4; MIC Comments, Docket No. NHTSA-2008-0150-0017.1 at 3.
---------------------------------------------------------------------------

    These commenters further stated that it similarly thought the
reference to category 3-5 in Table 4 (Performance requirements, Power-
assisted braking system failure test) should be category 3-4 because
category 3-5 vehicles will carry split service systems or combined
break systems (CBS) and are covered in the subsequent section of Table
4.\35\
---------------------------------------------------------------------------

    \35\ Id.
---------------------------------------------------------------------------

    Agency Response: The regulatory text of the NPRM was based on a
version of the GTR in which the definitions for category 3-4
motorcycles and category 3-5 motorcycles were listed incorrectly.
Specifically, the category 3-4 and 3-5 notations were actually
interchanged with each other. This error was addressed in the GTR by a
correction document which stated that the text ``3-4'' as it appears
throughout the GTR shall be replaced with ``3-5,'' and the text ``3-5''
shall be replaced with the text ``3-4.'' \36\ This correction results
in the GTR associating category 3-4 requirements with sidecar-equipped
motorcycles and category 3-5 requirements with symmetric three-wheeled
motorcycles, or ``trikes,'' as intended.
---------------------------------------------------------------------------

    \36\ See Global Technical Regulation No. 3, Corrigendum 1,
Motorcycle Brake Systems, U.N. Doc. ECE/TRANS/180/Add.3/Corr.2 (Jan.
29, 2008), available at http://www.unece.org/trans/main/wp29/wp29wgs/wp29gen/wp29registry/gtr3.html (last accessed April 26,
2010).
---------------------------------------------------------------------------

    Because the regulatory text of the NPRM corresponded closely with
that of the GTR, this mix-up was carried forward in the NPRM. Thus,
there are a variety of inconsistencies in the requirements for category
3-4 and category 3-5 motorcycles throughout the NPRM regulatory text.
This includes Table 2 as noted by the commenters. Although the
definitions of ``Category 3-4 motorcycle'' and ``Category 3-5
motorcycle'' given in paragraph S4 of the proposed regulatory text are
correct, most of the subsequent occurrences throughout the regulatory
text are incorrect. This mistake is easily remedied by replacing ``3-
4'' with ``3-5,'' and vice versa, in each place where requirements
apply to one or the other category. We have corrected the final rule
regulatory text by applying these corrections in each appropriate
instance. Concerning Table 2, to maintain the desired ordering of
categories, we have moved each stopping distance specification listed
for category 3-5 to the corresponding category 3-4 row, and listed
``not applicable'' in each category 3-5 row. Finally, we have made a
related clarification in subsection S<IP_ADDRESS>(d)(3) of the regulatory
text, to add a specification of category 3-5.
    ``Lightly loaded'' definition. The MIC commented that in the
parenthetical included in this definition, it was unclear as to which
paragraphs the text was intending to refer.\37\ The proposed definition
of ``lightly loaded'' referred to ``paragraphs 4.9.4 to 4.9.7'' in a
parenthetical, and no such paragraphs existed in the proposed
regulatory text.
---------------------------------------------------------------------------

    \37\ MIC Comments, Docket No. NHTSA-2008-0150-0017.1 at 3.
---------------------------------------------------------------------------

    Agency Response: The proposed range quoted above was referring to
the requirements as they were listed in the GTR. The proposed rule
should have listed the paragraphs as they were associated with the
proposed regulatory text. The GTR paragraphs referenced are a series of
the ABS test procedures. The corresponding paragraphs in NHTSA's
proposed regulatory text were S6.9.4 through S6.9.7. We have made this
change in the final regulatory text.
    ``Unladen vehicle mass'' definition. The MIC suggested that the
proposed definition of ``lightly loaded'' should use the term
``motorcycle,'' as opposed to the term ``vehicle'' in the
definition.\38\ They suggest that perhaps ``motorcycle'' should be used
in place of the term ``vehicle'' elsewhere in the proposed standard as
well.
---------------------------------------------------------------------------

    \38\ Id.
---------------------------------------------------------------------------

    Agency Response: Although the term ``motorcycle'' is used
throughout the current FMVSS No. 122, we are not making this change as
the commenter suggested. The term ``vehicle'' is the one used in the
GTR's regulatory definitions as well as in the UN Doc. S.R.1, which is
the source document for the vehicle categorization used in the GTR. For
these reasons, and in order to streamline the GTR and to maximize the
benefits of harmonization, we are in favor of keeping the term
``vehicle'' as used throughout the proposed regulatory text.
    CBS. Bosch commented that electro-mechanical CBS (eCBS) should be
distinguished from conventional CBS because the failure mode for eCBS
is different from CBS.\39\ Bosch suggested that the paragraph S4
definitions should exclude eCBS and that this could be accomplished by
rewording the definition for each motorcycle category to say that CBS
is ``A service brake system * * * mechanically linked and actuated by a
single control.''
---------------------------------------------------------------------------

    \39\ Bosch Comments, Docket No. NHTSA-2008-0150-0016.1.
---------------------------------------------------------------------------

    Bosch differentiates eCBS from conventional CBS because eCBS
systems have no mechanical or hydraulic link between the front and rear
brake circuits. With eCBS, the activation of a front or rear service
brake by a rear or front brake control, respectively, is accomplished
by purely electronic means. Bosch stated that the distinction between
eCBS and conventional CBS is important because the failure mode for
eCBS is different than for CBS, i.e., failed eCBS performs just like
conventional, separate front and rear brakes. Bosch explained that
``[a]n eCBS is subject to system failure, deactivation, and
degradation, which results in a system that is functionally equivalent
to a non-CBS with the corresponding performance limits.'' \40\
---------------------------------------------------------------------------

    \40\ Id. at 2.
---------------------------------------------------------------------------

    Bosch commented that their proposed re-definition to make eCBS
subject only to the performance requirements for single brake systems
(outlined above) is appropriate because of unique characteristics of
eCBS that are not accounted for in the proposed rule. Bosch pointed out
that an eCBS, unlike a CBS, may be equipped with a deactivation switch,
a low-speed mode, speed-dependent brake force distribution, or a
variety of rider-selectable modes that tune the system for riding
conditions. Bosch stated that, ``[t]hese additional eCBS
characteristics differentiate an eCBS from a CBS and prescribe that the
performance

requirements for a CBS are not always applicable for an eCBS.'' \41\
---------------------------------------------------------------------------

    \41\ Id.
---------------------------------------------------------------------------

    Bosch suggested that, as an alternative to excluding eCBS from the
regulatory definitions, NHTSA could instead define eCBS separately from
CBS and provide separate performance requirements to account for the
different eCBS failure modes, similar to the way that ABS electrical
failure is treated in S6.9.8 of the proposed FMVSS No. 122 regulatory
text.\42\ According to Bosch, this would have to include an exception
to the performance requirements defined in Table 2.
---------------------------------------------------------------------------

    \42\ Id. at 3.
---------------------------------------------------------------------------

    Agency Response: Bosch's comment suggests that NHTSA should include
specific test procedures to address the possibility of a failed eCBS
system. As Bosch acknowledges, this would entail defining eCBS
separately from CBS, and/or adding separate test procedures for eCBS.
If separate test procedures were added, eCBS would be treated similarly
to ABS, for which the NPRM has special procedures, including the
electrical failure test of S6.9.8.
    Bosch seems to suggest that system failure is more likely in the
case of an eCBS than a conventional, mechanical CBS, which would seem
logical because of the purely electronic link between front and rear
brake circuits. Certainly, eCBS could be designed so as to be readily
deactivated, such as by equipping the motorcycle with an on/off switch
for that purpose. In contrast, deactivation would not necessarily be
easily accomplished with conventional CBS, but much would depend on the
details of the CBS system design.
    Since eCBS systems currently are not in use, it is difficult for us
to evaluate whether adding specific test procedures to address eCBS
system failure is appropriate. Furthermore, in the FMVSS No. 122
proposal, there were no CBS-specific requirements that an eCBS would or
should be incapable of meeting, nor is eCBS addressed in the GTR
separately from CBS. Since the GTR does not include any proposal for
failed CBS performance and since no eCBS system is currently available
commercially, the agency believes that establishing failed systems
performance requirements for eCBS would be premature. Therefore, we are
electing not to make any changes related to eCBS at this time, but we
will evaluate in the future whether such accommodations are necessary.

B. Measurement of Performance Using Stopping Distance

    The GTR specifies stopping performance requirements in terms of
both stopping distance and MFDD. The NPRM proposed stopping distance as
the sole compliance criterion for several performance tests in proposed
FMVSS No. 122 because, as noted in the proposal, stopping distance is a
longstanding compliance criterion in FMVSS No. 122 as well as in
NHTSA's standards for brake performance of both light vehicles and
heavy vehicles.\43\ We further stated that the Executive Committee of
the 1998 Agreement and WP.29 are aware that the U.S. intended to make
these choices as allowed in the GTR.
---------------------------------------------------------------------------

    \43\ FMVSS No. 122 NPRM, 73 FR at 54034.
---------------------------------------------------------------------------

    Harley-Davidson, Honda, and the MIC each suggested that the agency
should include the alternative criterion of MFDD, which is a calculated
value based on both speed and stopping distance measurements.\44\ MFDD
and stopping distance are both included in the GTR as alternative
performance measures in several of the performance tests.
---------------------------------------------------------------------------

    \44\ See Honda Comments, Docket No. NHTSA-2008-0018.1 at 2; MIC
Comments, Docket No. NHTSA-2008-0150-0017.1 at 2; Harley-Davidson
Comments, Docket No. NHTSA-2008-0150-0012 at 2.
---------------------------------------------------------------------------

    Harley-Davidson commented that, based on its significant experience
with MFDD, a vehicle that passes the stopping distance measure will
also pass MFDD. Harley-Davidson also commented that the GTR and the
UNECE Regulation No. 78 allow either measure to be used. Further,
Harley-Davidson stated that some of the international inspection
agencies prefer MFDD, and that MFDD removes human factors from brake
performance testing. Harley-Davidson pointed out that an MFDD-like
procedure is already incorporated into the proposed regulatory text,
specifically in proposed section S<IP_ADDRESS>(d)(1) pertaining to heat fade
tests.\45\ Harley-Davidson stated that as a result of inclusion of MFDD
into the heat fade test requirements, manufacturers and test facilities
will be required to apply MFDD for some measures. Finally, Harley-
Davidson noted that the commentary accompanying the GTR recommends
using the MFDD measure ``to maintain consistency in the results.''
---------------------------------------------------------------------------

    \45\ Although Harley-Davidson's comments referred to this
provision as part of the ``wet fade tests,'' we will refer to the
referenced proposed tests as the ``heat fade tests,'' consistent
with the NPRM.
---------------------------------------------------------------------------

    Honda likewise requested that MFDD be included in NHTSA's final
rule. Honda commented that the GTR did not give individual regulating
bodies the discretion to exclude MFDD. Honda stated that the ``GTR does
not specify the option for each region to select only one method of
measurement.'' Further, Honda noted that ``the MFDD method has been
utilized by Honda as the primary method for determining stopping
performance and has found it to be more reliable and repeatable than
the distance method.''
    Similarly, the MIC pointed out that the GTR includes both MFDD and
stopping distance as alternative performance criteria, which allows the
manufacturer to choose to measure brake performance by either
deceleration or stopping distance. It also noted that deceleration-
based performance tests are already part of NHTSA's proposal, in
proposed paragraphs S6.6.3 et seq., and in paragraph S5.3.2, which
refers to ``continuous deceleration recording.'' The MIC took issue
with the rationale NHTSA gave for excluding MFDD:

    The reason given [in the NPRM] for mandating brake performance
measurement exclusively by stopping distance is ``to enhance the
enforceability of the Standard as opposed to providing optional
performance measures,'' and that ``this is consistent with how
performance requirements are stated in other Federal Motor Vehicle
Safety Standards.'' We don't agree that either is sufficient to
justify departure from the GTR and not in the best interest of
harmonization.

    The MIC, Harley-Davidson, and Honda each requested that NHTSA
incorporate the MFDD as an alternative performance measure in all
appropriate tests in the final rule.
    Agency Response: We are declining to adopt these commenters'
suggestions to allow manufacturers a choice of performance measures in
certain performance tests. As explained below, providing manufacturers
with an option for compliance in FMVSS test procedures is not common
because it presents a substantial enforcement difficulty for the
agency. Moreover, NHTSA participated in the development of the GTR and
during that process reached agreement with the other parties that we
would continue to use stopping distance in all appropriate FMVSS No.
122 test procedures. The inclusion of a stopping distance measurement
procedure was an important factor in U.S. approval of the GTR.
    When NHTSA stated in the NPRM that specifying stopping distance
enhances enforceability and referenced other FMVSSs to explain how
performance criteria are specified elsewhere by the agency, we meant
that for various reasons (detailed below)

NHTSA believes stopping distance is a better performance criteria than
a measurement of deceleration, and we do not ordinarily provide
manufacturer options for compliance because it can create an
enforcement problem for the agency. For example, if we allow two
different measures of braking performance in FMVSS No. 122 and, when
testing for compliance, NHTSA measures stopping distance and finds a
failure to meet the minimum stopping distance requirement test, NHTSA
would then be required to conduct additional testing to calculate MFDD.
    Additionally, we believe that stopping distance is a preferable
measurement of performance because MFDD assumes a certain level of
brake system responsiveness and does not consider performance over the
entire braking event. We believe the stopping distance measure is less
design-restrictive because it allows a manufacturer to develop brake
performance for the entire range of a braking event. Similarly, since
it accounts for the distance traveled between the time a brake lever or
pedal is applied and the time the motorcycle actually begins to
decelerate, stopping distance addresses the potential problem of slow-
acting brake systems.
    Further, none of the commenters presented any new information on
this issue. Nor did any commenter present data to support assertions
about accuracy of MFDD, for example, that MFDD is ``more reliable and
repeatable than the distance method.'' \46\ Since stopping distance is
used as one of the measured values in the equation for calculating
MFDD, the accuracy of MFDD depends to a great extent on stopping
distance accuracy. MFDD is not a measured value but is calculated using
measurements of speed and stopping distance. Because it is a factor in
the MFDD calculation, stopping distance still would have to be measured
even if MFDD was the specified compliance criterion in the NHTSA
standard. Consequently, there is little additional test burden in
having to collect stopping distance data.
---------------------------------------------------------------------------

    \46\ Honda Comments, Docket No. NHTSA-2008-0018.1 at 2.
---------------------------------------------------------------------------

    In response to the commenter that stated that the commentary
accompanying the GTR recommends using the MFDD measure ``to maintain
consistency in the results,'' we point out that this GTR preamble
language was referring to the difference between the UNECE Regulation
No. 78 specification of MFDD, and the JSS 12-61 specification of
vehicle mean saturated deceleration (MSD). In the relevant portion of
the GTR preamble, the text was discussing the difference between MFDD
and MSD, and then stated that ``[i]n order to maintain consistency in
the results, the MFDD was adopted [instead of MSD] to measure braking
deceleration performance.'' \47\ Thus, NHTSA does not believe this
phrase should be taken out of context and used to characterize the GTR
preamble discussion of MFDD versus stopping distance. In the GTR, the
performance requirements for the different tests were as specified in
the respective national regulation on which the test was based.
However, based on U.S. insistence, where the basis of a test was
performance measured by MFDD, the GTR also specified a stopping
distance equivalent performance measure, since the U.S. would not
support a GTR that specified only measurement of performance using
MFDD. All GTR performance requirements refer to both measurements of
stopping distance and MFDD in the table in paragraph 4.3.3 of the
GTR.\48\
---------------------------------------------------------------------------

    \47\ See Docket No. NHTSA-2008-0150-0002.1 at 11-12.
    \48\ Id. at 40.
---------------------------------------------------------------------------

    In response to Harley-Davidson's observation that the heat fade
test measures performance by referring to MFDD, we do not agree. The
commenter referenced proposed paragraph S<IP_ADDRESS>(d)(1), which describes
the force that is to be applied to the brake lever when actuated during
the heating stops: ``For the first stop: The constant control force
that achieves a vehicle deceleration rate of 3.0-3.5 m/s \2\ while the
vehicle is decelerating between 80 percent and 10 percent of the
specified speed.'' Since this specification is a way to determine
force, stopping distance is not appropriate here. Further, the
specified braking force to heat the brakes is not a performance
requirement. In that paragraph, the test rider is just heating the
brake. Paragraph S6.7.4, Hot brake stop--test conditions and procedure,
then specifies how to test the hot brakes and paragraph S6.7.5,
Performance requirements, specifies the comparative performance
requirements between the baseline stop measurements and the hot brake
stop measurements, in terms of stopping distance. Therefore, the use of
a deceleration specification to describe the actuation force that a
test rider is to use in the heat fade test is not inconsistent with the
use of stopping distance for all performance measurements.
    The MIC similarly commented that proposed paragraph S5.3.2
describes ``continuous deceleration recording,'' and stated that
proposed paragraphs S6.6.3 et seq. reference deceleration measurements
for wet and heat fade conditions even though it is not called MFDD. As
explained above, the heat fade test does not describe performance
requirements in terms of deceleration, but merely uses deceleration to
specify how to determine how much force to apply to a brake when a test
rider is actuating the brake for the purpose of heating it. The
deceleration measurement specified in section S6.6.3 (wet brake test)
is for average deceleration over the whole duration of the stop in
accordance with paragraph S5.3.2. This is not the same as MFDD as the
MIC suggested. MFDD is the vehicle deceleration calculated between 80
and 10 percent of the vehicle initial speed, not the deceleration from
initial speed to full stop.
    NHTSA notes that the 100 km/h dry stop test that was developed from
the current FMVSS No. 122 specifies performance in terms of stopping
distance only. It does not specify a deceleration-based criterion like
MFDD. Similarly, the ABS stopping distance performance tests on low and
high friction surfaces specify performance measures in terms of
stopping distance only. Hence, in these tests, there is no alternative
to measuring and recording stopping distance.
    Finally, we note that the use of stopping distance in the FMVSS
does not preclude the use of MFDD by manufacturers or other parties. As
long as there is a basis for correlating with the FMVSS method, the
test procedure used to certify a motorcycle brake system is left to the
manufacturer's discretion. Specifically, FMVSSs do not require
manufacturers to test every motor vehicle or piece of motor vehicle
equipment (e.g., tires) to the specifications in each safety standard.
The FMVSSs set performance standards that motor vehicles and motor
vehicle equipment must meet when tested by the agency in accordance
with the test procedures specified in the FMVSS associated with that
performance requirement. Under the Motor Vehicle Safety Act, ``a
manufacturer or distributor of a motor vehicle or motor vehicle
equipment [must] certify * * * that the vehicle or equipment complies
with applicable [FMVSSs].'' \49\ Under this enforcement mechanism,
known as ``self certification,'' the burden for ensuring that all new
vehicles and equipment comply with Federal regulations is borne by the
manufacturer. NHTSA does not perform any pre-sale testing, approval, or

certification of vehicles or equipment, whether of foreign or domestic
manufacture, before introduction into the U.S. retail market. To ensure
compliance with agency regulations, NHTSA randomly tests certified
vehicles or equipment (in accordance with the test procedures laid out
in the regulations) to determine whether the vehicles or equipment fail
to comply with applicable standards. For such enforcement checks, NHTSA
purchases vehicles and equipment, which are then tested according to
the procedures specified in the standards. If the vehicle or equipment
passes the test, no further action is taken. If the vehicle or
equipment fails, NHTSA has the authority to request additional
information from the manufacturer on the basis for certification and to
assess civil penalties for any confirmed violation.\50\
---------------------------------------------------------------------------

    \49\ 49 U.S.C. 30115(a).
    \50\ See, e.g., 49 U.S.C. 30165, 30166 (safety standards); 49
U.S.C. 32308, 32309 (consumer information); 49 U.S.C. 32507 (bumper
standards); 49 U.S.C. 32706, 32709 (odometer fraud).
---------------------------------------------------------------------------

    Neither the National Traffic and Motor Vehicle Safety Act \51\ (nor
other statutes NHTSA administers) nor NHTSA standards and regulations
require that a manufacturer base its certifications on any particular
tests, any number of specified tests or, for that matter, any tests at
all. A manufacturer is required to exercise due care in certifying its
motor vehicles. It is the responsibility of the manufacturer to
determine initially what test results, computer simulations,
engineering analyses, or other information it needs to enable it to
certify that its vehicles comply with applicable Federal safety
standards. Thus, manufacturers and test laboratories can measure
performance using stopping distance, or another method, for their own
certification purposes as long as they can reasonably correlate test
results using their chosen method with those using the FMVSS procedure
and show that their certification tests provide a sound basis for
compliance with the safety standard.
---------------------------------------------------------------------------

    \51\ National Traffic and Motor Vehicle Safety Act of 1966,
Public Law 89-563, 80 Stat. 718 (1966) (now codified, as amended, at
49 U.S.C. 30101 et seq.).
---------------------------------------------------------------------------

C. Motorcycle Test Speed and Corrected Stopping Distance

    The GTR set deceleration or stopping distance performance
requirements for a specified initial test speed. While professional
test riders can approach this initial test speed, it is unlikely that
the test will be started at the exact speed specified, affecting the
stopping distance measurement. The current FMVSS No. 122 does not
specify a speed tolerance for this potential variation, but consistent
with the GTR, the proposed rule specified Japan's existing general
tolerance of  5 km/h in S6.1.4.
    As explained in the NPRM, a method for correcting the measured
stopping distance (in the event of the actual test speed deviating from
the specified test speed, but within the  5 km/h tolerance)
was proposed to compensate for the difference between the specified
test speed and the actual speed where the brakes were applied (see
S5.3.1(b)).\52\ The MIC commented that the paragraph S6.1.4 reference
to the proposed corrected stopping distance method in the proposed
regulatory text appeared to be incorrect.\53\
---------------------------------------------------------------------------

    \52\ FMVSS No. 122 NPRM, 73 FR at 54024.
    \53\ MIC Comments, Docket No. NHTSA-2008-0150-0017.1 at 3.
---------------------------------------------------------------------------

    Agency Response: We agree with the MIC. Paragraph S6.1.4 of the
proposed regulatory text referred to the stopping distance correction
formula as being in paragraph S5.3.2(b). The actual stopping distance
correction formula was listed in paragraph S5.3.1(b), as noted by the
MIC. NHTSA has corrected this inaccurate reference in the final
regulatory text.

D. Peak Braking Coefficient

    The peak braking coefficient (PBC) is a measure of the coefficient
of friction of the test surface and is an important parameter in
evaluating the brake performance of a vehicle. PBC is effectively
equivalent to the peak friction coefficient (PFC) as defined in FMVSS
No. 121, Air brake systems, and FMVSS No. 135, Light vehicle brake
systems. The GTR specifies test surface conditions, one of which is
that the high-friction ``test surface has a nominal [PBC] of 0.9,
unless otherwise specified.'' As explained in the NPRM, for reasons of
objectivity, we specified in the proposed rule a PBC equal to 0.9 for
the high-friction dry test surface used for the motorcycle brake system
tests.
    FMVSS No. 122 currently specifies that the road tests be conducted
on an 8-foot-wide level roadway having a skid number of 81. The skid
number is also a measure of the coefficient of friction of the test
surface and is derived by measuring the friction using a locked wheel,
whereas the PBC is derived by measuring the peak surface friction
before wheel lockup occurs. PBC is a more relevant surface friction
measurement for non-locked wheel tests, such as those included in FMVSS
No. 122 and in the GTR. Other Federal motor vehicle safety standards
for braking systems, FMVSS No. 121 and FMVSS No. 135, specify the road
test surface using a PBC of 0.9 when measured using the American
Society for Testing and Materials (ASTM) E1136-93 (Reapproved 2003)
standard reference test tire, in accordance with ASTM Method E1337-90
(Reapproved 2002), at a speed of 40 mph without water delivery.
    As explained in the NPRM, the GTR defines the test surface using a
PBC value instead of a skid number value since peak braking coefficient
is a more representative measure of the type of braking tests performed
in the requirements with a rolling tire. However, the decision was made
to not specify the method used to measure the coefficient of friction
but leave it to the national regulations to specify which of the above
test methods should be used to measure PBC. In the U.S., the ASTM
Method for measuring PBC to define surface friction has been included
in Federal motor vehicle safety standards since the early-1990's and
was also used by the U.S. automotive industry prior to that date.
Accordingly, the agency proposed that the PBC of the test surface will
be measured using the ASTM E1136-93 (Reapproved 2003) standard
reference test tire, in accordance with ASTM Method E1337-90
(Reapproved 2002). The GTR maintains an option for Contracting Parties
to specify in their respective national regulations the value of PBC
for the high-friction dry test surface used for the motorcycle brake
system tests.
    PBC Measurement Methodology. Three commenters requested that NHTSA
allow use of the test vehicle itself to define PBC as described in the
GTR. Harley-Davidson requested that the agency reconsider our intent
``to allow only ASTM [E1337-90] to determine road surface peak braking
coefficient.'' \54\ Harley-Davidson stated that, although NHTSA has a
history of using the ASTM method, the use of the test vehicle itself to
determine wheel lock threshold, as allowed by UNECE Reg. No. 78, is a
widely used procedure that is well understood within the motorcycle
industry. Harley-Davidson commented that the ASTM method involves the
use of additional test equipment, and adds further complexity and costs
to the testing process, while NHTSA has acknowledged that the two
methods yield comparable results.
---------------------------------------------------------------------------

    \54\ Harley-Davidson Comments, Docket No. NHTSA-2008-0150-0012
at 2.
---------------------------------------------------------------------------

    The MIC commented that the intention of the GTR was for both the
ASTM method and the alternative UNECE Reg. No. 78 method to be

available as test options.\55\ The MIC stated that the choice of method
should be up to the manufacturer or other testing entity. The MIC also
pointed out that in some circumstances, where length and width of the
test course are limited, the ASTM E1337-90 method cannot be performed.
---------------------------------------------------------------------------

    \55\ MIC Comments, Docket No. NHTSA-2008-0150-0017.1 at 1.
---------------------------------------------------------------------------

    Honda expressed a more specific difficulty regarding the PBC
measurement. Honda stated that it has utilized a test facility that
cannot accommodate the ASTM E1337-90 procedure due to its relatively
small size.\56\ Honda stated that it would have to move its manpower,
vehicles, and testing equipment from its current on-site location to a
much more distant one in order to accommodate the ASTM E1337-90 test
procedure, and that having to do so would be very burdensome and
expensive and could force product development delays. Additionally,
Honda stated that moving testing to other Honda facilities would also
cause schedule conflicts with testing of other on-road products, and
may ultimately force Honda to build additional testing facilities at
great expense.
---------------------------------------------------------------------------

    \56\ Honda Comment, Docket No. NHTSA-2008-0150-0018.1 at 2.
Honda gave no further details, but we assume the inability of its
test facility to accommodate the ASTM E1337-90 method has to do with
the additional track length needed to get a skid trailer up to the
test speed of 64 km/h and maintain that speed while braking the
trailer's test wheel, compared to the relatively shorter distance
required to do the same from 60 km/h with a test motorcycle while
braking it to a stop.
---------------------------------------------------------------------------

    Agency Response: The GTR leaves to individual national legislation
the methodology that is selected for measurement of test surface
friction. The text of the GTR makes this clear in paragraph <IP_ADDRESS>,
Measurement of PBC, which states that ``PBC is measured as specified in
national or regional legislation using either: (a) [the ASTM E1337-90
test method]; or (b) [the UNECE Reg. No. 78 method].'' \57\ Similarly,
the formal statement of technical rationale and justification that
precedes the GTR regulatory text states that the ``Contracting Parties
[] agreed to list both methods in the regulatory text of the GTR, but
decided to leave it to the national regulations to specify which of the
above test methods should be used to measure the PBC.'' \58\ The use of
the phrase ``which of the above test methods'' in this preamble
statement makes clear that the Contracting Parties intended that
national regulations adopting the GTR could adopt either of the listed
test methods.
---------------------------------------------------------------------------

    \57\ See Global Technical Regulation No. 3, Amendment 1,
Motorcycle Brake Systems, U.N. Doc. ECE/TRANS/180/Add.3/Amend.1
(July 31, 2008); Global Technical Regulation No. 3, Motorcycle Brake
Systems, U.N. Doc. ECE/TRANS/180/Add.3 (Dec. 21, 2006), available at
http://www.unece.org/trans/main/wp29/wp29wgs/wp29gen/wp29registry/gtr3.html (last accessed April 27, 2010).
    \58\ Global Technical Regulation No. 3, Motorcycle Brake
Systems, U.N. Doc. ECE/TRANS/180/Add.3 at 11 (Dec. 21, 2006).
---------------------------------------------------------------------------

    Thus, consistent with the GTR, this final rule specifies that
measurement of the PBC is conducted in accordance with the ASTM E1337-
90 test method, or the first option in paragraph <IP_ADDRESS> of the GTR, as
proposed.\59\ NHTSA's selection of the ASTM method represents what we
consider to be a well-defined baseline that is appropriate for use in a
safety standard. As explained above, other FMVSSs specify the ASTM
E1337-90 test method to measure peak braking coefficient. Thus, NHTSA
is immediately prepared to start testing in accordance with this test
method, as opposed to the UNECE Reg. No. 78 test method. While there
may, as a couple commenters noted, be no quantifiable safety benefit to
choosing one test method over the other, there is certainly an
enforcement concern for the agency, both because NHTSA does not have as
much experience conducting PBC measurements for compliance tests using
the UNECE Reg. No. 78 test method, and because proving noncompliance is
substantially more complicated when the agency provides manufacturers
with multiple options for compliance, as explained in section III.B
above.
---------------------------------------------------------------------------

    \59\ See proposed paragraph S<IP_ADDRESS>. FMVSS No. 122 NPRM, 73 FR
at 54039.
---------------------------------------------------------------------------

    As discussed above in section III.B, Federal motor vehicle safety
standards (FMVSSs) do not require manufacturers to test every motor
vehicle or piece of motor vehicle equipment to the specifications in
each safety standard. The FMVSSs set performance standards that motor
vehicles and motor vehicle equipment must meet when tested by the
agency in accordance with the test procedures specified in the FMVSS
associated with that performance requirement. Neither the National
Traffic and Motor Vehicle Safety Act \60\ (nor other statutes NHTSA
administers) nor NHTSA standards and regulations require that a
manufacturer base its certifications on any particular tests, any
number of specified tests or, for that matter, any tests at all. A
manufacturer is required to exercise due care in certifying its motor
vehicles. It is the responsibility of the manufacturer to determine
initially what test results, computer simulations, engineering
analyses, or other information it needs to enable it to certify that
its vehicles comply with applicable Federal safety standards. Thus,
manufacturers and test laboratories can use the UNECE Reg. No. 78
method, or another method, for their own certification purposes as long
as they can reasonably correlate test results using their chosen method
with those using the FMVSS procedure and show that their certification
tests provide a sound basis for compliance with the safety standard.
The GTR preamble explains that despite the differences in methodology,
``the ABS validation research program demonstrated that, when properly
conducted, both methods yield comparable results for evaluating the
test surface.'' \61\ Thus, it would appear that this approach will not
impose a great financial burden on manufacturers. This approach has a
longstanding history in brake system compliance tests.
---------------------------------------------------------------------------

    \60\ National Traffic and Motor Vehicle Safety Act of 1966,
Public Law 89-563, 80 Stat. 718 (1966) (now codified, as amended, at
49 U.S.C. 30101 et seq.).
    \61\ Global Technical Regulation No. 3, Motorcycle Brake
Systems, U.N. Doc. ECE/TRANS/180/Add.3 at 11 (Dec. 21, 2006).
---------------------------------------------------------------------------

    As a practical matter, we note that in the UNECE Reg. No. 78
method, the surface friction coefficient is determined by measuring the
maximum braking rate with ABS disabled, for the front wheel and rear
wheel brakes applied simultaneously, and with constant brake forces
applied throughout the tests. This is not practicable for some ABS-
equipped motorcycles where ABS cannot be disabled. This is a particular
concern since FMVSS No. 122, under the current amendment, for the first
time will include procedures specifically for ABS. For these reasons,
this final rule amends FMVSS No. 122 so that it will specify that when
NHTSA tests for the performance criteria listed in the standard, PBC
will be measured using the ASTM procedure.
    Nominal PBC versus PBC. Harley-Davidson urged NHTSA to reconsider
the language the agency chose for specifying the PBC measure of the
high-friction test surface, stating that the proposed language appears
to require an exact PBC measure of 0.9, rather than accepting a
``nominal PBC'' of 0.9.\62\ Harley-Davidson commented that it did not
understand NHTSA's intent in removing the term ``nominal'' and NHTSA's
reference to ``objectivity,'' other than as a desire for the agency to
maintain consistency with other NHTSA safety standards. Harley-Davidson
went on to state:
---------------------------------------------------------------------------

    \62\ Harley-Davidson Comments, Docket No. NHTSA-2008-0150-0012
at 2-3.

---------------------------------------------------------------------------

    Measures of PBC are meant to be a statement of a current
condition on a particular section of road. They are reported as an
average of measures and, in the case of ASTM E1337-90, as an average
of averages. Such a report is in the nature of ``nominal'' as we
understand the term. We are uncertain whether NHTSA is effectively
proposing to require vehicle manufacturers to expend extra resources
to develop the entire test surface to attain an actual PBC of 0.9
rather than accepting a report of the nominal condition of the same
test surface.

    Harley-Davidson also quoted a discussion that was included in the
technical rationale accompanying the GTR, at section <IP_ADDRESS>, which
lays out in detail the reasons why the GTR specifies a nominal PBC of
0.9 rather than an exact value.
    Honda also commented on this issue. Honda stated that ``[i]t is
difficult to maintain the PBC equal to exactly 0.9, and the parties
which contributed to the GTR discussed this issue many times, agreeing
to allow for slight variances.'' \63\ Honda stated that referring to an
exact PBC value would result in an unnecessary testing burden for which
there will be no safety benefit. Honda suggested that, should NHTSA
deem it necessary to specify a tolerance to improve objectivity, such a
tolerance should be included in the FMVSS No. 122 Test Procedure.\64\
---------------------------------------------------------------------------

    \63\ Honda Comment, Docket No. NHTSA-2008-0150-0018.1 at 2.
    \64\ For each FMVSS, NHTSA's Office of Vehicle Safety Compliance
(OVSC) publishes detailed Laboratory Test Procedures for the purpose
of providing guidelines for obtaining data in OVSC compliance
testing programs and a uniform data recording format for NHTSA
contractor laboratories. See http://www.nhtsa.gov/Vehicle+Safety/
Test+Procedures (last accessed April 29, 2010). In the near future,
NHTSA will likely revise the FMVSS No. 122 Test Procedure in
accordance with this final rule.
---------------------------------------------------------------------------

    The MIC comment raised similar concerns, saying that testing costs
will go up rather than be decreased, as described as a goal of the
proposal, if the required PBC is set at exactly 0.9.\65\ The MIC
stated:
---------------------------------------------------------------------------

    \65\ MIC Comments, Docket No. NHTSA-2008-0150-0017.1 at 1-2.

    We agree that objectivity is desirable if the inclusion of an
absolute is useful. However, in this application we do not believe
it is either useful or desirable. It's difficult to set the PBC
equal to 0.9 and this is recognized in the GTR that describes the
attributes of the high-friction brake surface as having ``a nominal
peak braking coefficient (PBC) of 0.9.'' We are not suggesting a
specific tolerance, but believe nominal, based on best engineering
practices, is essential to satisfactorily perform the test or
achieve repeatability and should not have been deleted from the GTR
---------------------------------------------------------------------------
language.

    Agency Response: Inclusion of the ``nominal'' descriptor in
specifying the PBC of the test surface is unacceptable from a
compliance standpoint because it represents an unstated range of
values. Specifying ``nominal PBC'' fails to limit the friction
coefficient in an objective or useful way. Under the National Traffic
and Motor Vehicle Safety Act, FMVSSs prescribed by NHTSA must be
``stated in objective terms.'' \66\
---------------------------------------------------------------------------

    \66\ 49 U.S.C. 30111(a). See Chrysler Corp. v. NHTSA, 472 F.2d
659, 675 (6th Cir. 1972) (discussing Congressional intent and
explaining that ``objective criteria are absolutely necessary so
that the question of whether there is compliance with the standard
can be answered by objective measurement and without recourse to any
subjective determination'').
---------------------------------------------------------------------------

    The agency's intent is not to require that high-friction brake
tests be conducted only on surfaces with a PBC of exactly 0.9. Rather,
the intent is to set a target PBC that acts as a reference point. In
this way, those who are involved with brake system development, such as
motorcycle manufacturers, can use test surfaces with any PBC below 0.9
in order to ensure compliance at least at the 0.9 level.\67\ On the
other hand, NHTSA, and laboratories conducting compliance tests, would
use surfaces having a PBC of 0.9 or somewhat greater to allow a
reasonable margin for friction variations and other test surface
variables. As such, manufacturers are provided notice regarding what is
required under the standard.
---------------------------------------------------------------------------

    \67\ Surfaces with lower coefficients of friction are more
slippery than surfaces with higher friction coefficients, and thus
provide lower levels of braking force and poorer directional
stability and control during braking.
---------------------------------------------------------------------------

    Keeping in mind that FMVSS are established to set minimum
performance requirements, manufacturers presumably would want to design
to a level that exceeds the minimum.\68\ We believe specifying a PBC of
0.9 without further qualification is the best way to identify exactly
what the safety standard requires and to eliminate the need for
interpretation as to what is expected for compliance.
---------------------------------------------------------------------------

    \68\ See 49 U.S.C. 30102(a)(8) (defining ``motor vehicle safety
standard'' as a ``minimum standard for motor vehicle or motor
vehicle equipment performance'').
---------------------------------------------------------------------------

    This approach of specifying an unqualified PBC is consistent with
how surface peak friction coefficients are specified in FMVSS No. 121,
Air Brake Systems,\69\ FMVSS No. 135, Light Vehicle Brake Systems,\70\
and in FMVSS No. 126, Electronic Stability Control Systems.\71\ FMVSS
No. 126 mandates Electronic Stability Control (ESC) systems on light
vehicles, and establishes test procedures to ensure that ESC systems
meet minimum requirements. In the rulemaking that established FMVSS No.
126, NHTSA originally proposed a tolerance around the surface PBC
specification, but ultimately specified simply a PBC of 0.9 for the
test surface in the final rule.\72\ The agency explained that, although
the proposed tolerance was an attempt to increase objectivity, such a
tolerance created the possibility of compliance tests for FMVSS No. 126
being performed on lower friction coefficient surfaces than those for
other braking standards, which is not the intention. NHTSA explained
that while it is unlikely that any facility has a surface with exactly
that friction coefficient, compliance testing for other braking
standards is performed on a surface with a PBC/PFC slightly higher than
the specification, i.e., slightly less-slippery than the surface
required, which creates a margin for clear enforcement. Here, as in the
ESC final rule, we will continue to use consistent compliance test
conventions across all FMVSSs, and specify an unqualified surface PBC.
---------------------------------------------------------------------------

    \69\ See 49 CFR 571.121, S<IP_ADDRESS>, S<IP_ADDRESS>, S6.1.7.
    \70\ See 49 CFR 571.135, S6.2.1.
    \71\ See 49 CFR 571.126, S6.2.2.
    \72\ Federal Motor Vehicle Safety Standards, Electronic
Stability Control Systems, Controls and Displays; Final Rule, 72 FR
17236, 17267-17268 (2007).
---------------------------------------------------------------------------

E. Test Sequence

    The NPRM proposed a specific testing order to eliminate any
potential effect of the test sequence on braking performance and to
harmonize with the GTR. The proposed sequence was selected based on
increasing severity of the test on the motorcycle and its brake
components, in order to preserve the condition of the brakes.
    The current FMVSS No. 122 specifies a particular sequence in which
tests should be conducted, ending with the wet brake test. The fade
test would have the greatest effect on the condition of the motorcycle
brakes, which could affect brake performance in subsequent tests. For
this reason, current FMVSS No. 122 specifies that a re-burnishing be
conducted after the fade test, to refresh the brake components. In
order to eliminate the need for re-burnishing, the GTR specifies that
the fade test be the last of the motorcycle brake system performance
tests.
    The ABS test would be the next most severe test, which will result
in braking at or near the limits of traction. Thus, the GTR specifies
that the ABS test would precede the fade test, for motorcycles equipped
with ABS. The remaining tests are not as severe on the brake system and
tires, therefore the GTR sequenced them according to increasing test
speed for the dry stop

performance tests, followed by the wet brake performance test.
Consistent with the GTR, we proposed to specify the test sequence using
a table in the regulation. The proposed test sequence table was
identical to Table 1 here.

                     Table 1--Proposed Test Sequence
------------------------------------------------------------------------
                        Test order                            Paragraph
------------------------------------------------------------------------
1. Dry stop--single brake control actuated................         S6.3
2. Dry stop--all service brake controls actuated..........         S6.4
3. High speed.............................................         S6.5
4. Wet brake..............................................         S6.6
5. Heat fade*.............................................         S6.7
6. If fitted:
  6.1. Parking brake system...............................         S6.8
  6.2. ABS................................................         S6.9
  6.3. Partial failure, for split service brake systems...         S6.10
  6.4. Power-assisted braking system failure..............         S6.11
------------------------------------------------------------------------
* Heat fade is always the last test to be carried out.

    Harley-Davidson and the MIC both stated that the test sequence in
Table 1 would be clearer if the procedures listed as items No. 5 and
No. 6 were reversed.\73\ They suggested that the heat fade test, listed
as No. 5 in Table 1, should be listed last since it is always the last
test in the sequence, even if procedures under No. 6 are required.
---------------------------------------------------------------------------

    \73\ MIC Comments, Docket No. NHTSA-2008-0150-0017.1 at 3;
Harley-Davidson Comments, Docket No. NHTSA-2008-0150-0012 at 5.
---------------------------------------------------------------------------

    Agency Response: We note that the order in which the test
procedures were listed in Table 1 corresponded to the paragraph number
sequence of the regulatory text of the proposed safety standard. Also,
the procedures listed under No. 6 in Table 1 are required only for
certain equipment which may not be fitted to the test motorcycle, e.g.,
a parking brake or power-assisted brakes. Nevertheless, we agree it is
clearer if the procedures appear in Table 1 in the same order in which
they are to be performed. Therefore, we are changing the table in the
regulatory text as requested, by putting the Heat Fade test at the end
of the list. Table 2 illustrates how the table appears in the final
regulatory text, which is referred to in paragraph S6.1.7, Test
Sequence.

        Table 2--Test Sequence Specified in Final Regulatory Text
------------------------------------------------------------------------
                        Test order                            Paragraph
------------------------------------------------------------------------
1. Dry stop--single brake control actuated................         S6.3
2. Dry stop--all service brake controls actuated..........         S6.4
3. High speed.............................................         S6.5
4. Wet brake..............................................         S6.6
5. If fitted:
  5.1. Parking brake system...............................         S6.8
  5.2. ABS................................................         S6.9
  5.3. Partial failure, for split service brake systems...         S6.10
  5.4. Power-assisted braking system failure..............         S6.11
6. Heat fade..............................................         S6.7
------------------------------------------------------------------------

F. Brake Application Force Measurement

    Controls for the application of the brakes can include hand and
foot actuated control levers. The various national standards and
regulations have slightly different brake control input force limits,
and in the case of a hand actuated control lever, there is also a
discrepancy as to the location of application of the input force. One
consistent element is the location and direction of application of the
input force to the foot actuated lever (i.e., pedal). Consistent with
the GTR, the NPRM proposed input forces for each test in accordance
with the national regulation on which the individual test is based, to
minimize confusion. The respective input forces are noted in Table 3. A
discussion on brake control actuation force specifications for
evaluating motorcycles equipped with ABS is provided below in paragraph
IV.G.

  Table 3--Input Forces on Hand and Foot Actuated Brake Control Levers
------------------------------------------------------------------------
                                  Foot control, FP     Hand control, FL
          Regulation                    (N)                  (N)
------------------------------------------------------------------------
FMVSS No. 122.................  25 < FP < 400        10 < FL < 245
UNECE Regulation No. 78/JSS 12- FP < 350             FL < 200
 61.
------------------------------------------------------------------------

    As discussed in the NPRM, with respect to the location of the input
force on the hand-controlled lever, in developing the GTR, there was
agreement that none of the three national regulations is clear enough
with respect to measuring the location of the input force on the hand-
controlled lever. In an effort to define a common practice, the GTR
includes a revised description for the location of the input force on
the control lever and its direction of application, based on ISO
8710:1995, Motorcycles--Brakes and braking devices--tests and
measurement methods. Consistent with the GTR, the NPRM proposed the
GTR's harmonized specification of input force in proposed paragraph
S6.2.3. NHTSA is adopting this specification as proposed since no
commenter mentioned this proposed requirement.
    Finally, for those motorcycles that use hydraulic fluid for brake
force transmission, the GTR stipulates that the master cylinder shall
have a sealed, covered, separate reservoir for each brake system. This
includes one or more separate reservoirs located within the same
container, such as commonly found on passenger cars. Such containers
may only have one sealed, covered filling cap. The proposed rule
incorporated these hydraulic service brake system requirements in
paragraph S5.1.9. Since no commenter mentioned this proposed regulatory
text, we are adopting these provisions as proposed.

G. Brake Temperature Measurement

    Brake test requirements typically specify that initial brake
temperature (IBT) be measured at the start of each braking performance
run to enhance test repeatability. The two measurement methods that are
generally used in brake standards and regulations worldwide include (1)
the use of plug-type thermocouples, and (2) the use of rubbing-type
thermocouples. We proposed to retain the plug-type thermocouples brake
temperature measurement method in FMVSS No. 122.
    The two methods of measuring the IBT were included in the GTR and
each Contracting Party could specify which temperature measurement
would be accepted in its national regulation.

FMVSS No. 122, as well as all the other brake standards in the Federal
motor vehicle safety standards, currently specifies the plug-type
thermocouple for measuring the initial brake temperature. NHTSA does
not have experience using the rubbing-type thermocouple either in brake
research or compliance testing. Given the limitations of the rubbing-
type thermocouple described in the NPRM, we continue to believe that
the plug-type thermocouple would be the more effective option for
measuring IBT in the updated FMVSS No. 122. We did not receive any
comment on this aspect of the proposal. Therefore, as in current FMVSS
No. 122 and as in the proposed rule, updated FMVSS No. 122 will specify
that initial brake temperature is measured by plug-type thermocouples.
    With respect to the actual brake temperature values specified for
testing purposes, consistent with the GTR, the NPRM proposed that FMVSS
No. 122 specify as a test condition an IBT between 55 [deg]C and 100
[deg]C in order to encompass all brake systems. Since no commenter
addressed this proposed test condition, today's final rule continues to
specify this IBT range as a test condition for each test procedure for
the reasons explained in the NPRM.

H. Burnishing Procedure

    The current FMVSS No. 122 includes a burnishing procedure. In order
to harmonize with the GTR, we proposed a slight variation of the
current procedure, to include some aspects of procedures currently used
by motorcycle manufacturers in preparation for UNECE Regulation No. 78/
JSS 12-61 type approval testing.
    The burnishing procedure serves as a conditioning of the foundation
brake components to permit the brake system to achieve its full
capability. Burnishing typically matches the friction components to
one-another and results in more stable and repeatable stops during
testing. All Federal motor vehicle safety standards for brake systems
(FMVSS Nos. 105, 121, 122, and 135) currently include a burnishing
procedure. The burnishing procedure of current FMVSS No. 122 specifies
200 stops with both brakes applied simultaneously, decelerating from a
speed of 30 mph at 12 fps\2\ with an IBT between 55 [deg]C and 65
[deg]C (130 [deg]F and 150 [deg]F).
    As explained in the NPRM, the burnishing procedure in the GTR is
based on FMVSS No. 122, but also includes some aspects of procedures
currently used by motorcycle manufacturers in preparation for UNECE
Regulation No. 78/JSS 12-61 type approval testing. For example, the GTR
specifies burnishing the brakes separately since this would result in a
more complete burnish for both front and rear brakes, as compared with
the current FMVSS No. 122 method of using both brakes simultaneously.
Hence, consistent with the GTR, the proposed rule specified that each
brake be burnished for 100 decelerations.
    Harley-Davidson commented that it may not be possible or necessary
in the case of combined or split-service brake systems to actuate each
brake separately for the burnishing procedure of the proposed rule.\74\
Harley-Davidson, thus, recommended appending language such as ``unless
a split service or combined brake system is present'' to the
S<IP_ADDRESS>(c) burnishing test procedure specification.
---------------------------------------------------------------------------

    \74\ Harley-Davidson Comments, Docket No. NHTSA-2008-0150-0012
at 4.
---------------------------------------------------------------------------

    Agency Response: The test condition specification in proposed
paragraph S<IP_ADDRESS>(c) (Brake application) stated, ``Each service brake
system control actuated separately.'' It did not say that the front and
rear brakes have to be applied separately. The proposed language
accurately conveys the intent of the requirement, which is that each
control, if there is more than one control on the motorcycle, be
actuated independently of any other brake controls.
    The language suggested by Harley-Davidson would not account for
combined brake systems having both hand lever and foot pedal controls.
Under the procedure in S<IP_ADDRESS>(c), such a system would be burnished by
applying the front lever of the CBS-equipped system (which could apply
both front and rear brakes to varying degrees, depending on the CBS
design) in a series of 100 stops, and then the burnishing would be
repeated using the rear lever or pedal of the CBS-equipped system
(which also could apply both front and rear brakes to varying degrees,
depending on the CBS design) in a second series of 100 stops.
    The intent of the contracting parties in developing separate
burnish for front and rear brakes was to ensure a more complete burnish
compared with the current FMVSS No. 122 where a 200-stop burnish
procedure is required with simultaneous application of both brake
controls. The current burnish procedure results in more variability of
the brake burnish since the test rider determines the mix of front to
rear brake forces used to attain the specified deceleration level
during the burnish stops. The GTR burnish procedure ensures a more
complete burnish for both brakes since each brake control is used
separately. We are aware that for CBS-equipped motorcycles, the burnish
procedure may provide a slightly higher level of burnish since a
portion of the front and rear foundation brakes may be activated by
both the hand lever and the foot pedal.
    NHTSA believes that the language of the proposed procedure in
S<IP_ADDRESS>(c) is consistent with our intent, and therefore, we elect not
to modify the proposal as requested in this comment. Since no commenter
mentioned any other aspect of the proposed burnishing procedure, we are
adopting the burnishing procedure as proposed, for the reasons
explained here and in the NPRM.\75\
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    \75\ See FMVSS No. 122 NPRM, 73 FR at 54026.
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I. Notice of Wear

    The NPRM proposed the GTR requirement that ``friction material
thickness shall be visible without disassembly, or where the friction
material is not visible, wear shall be assessed by means of a device
designed for that purpose.'' \76\ Current FMVSS No. 122 requires that
the ``brake system [ ] be installed so that the lining thickness of
drum brake shoes may be visually inspected, either directly or by use
of a mirror without removing the drums, and so that disc brake friction
lining thickness may be visually inspected without removing the pads.''
\77\ Allowing wear of friction material thickness to be assessed either
visually or by means of a device increases design freedom while serving
the same purpose of indicating friction material wear, without the need
for disassembly. We did not receive comment on this aspect of the
proposal and, therefore, are adopting this requirement as proposed.
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    \76\ See FMVSS No. 122 NPRM, 73 FR at 54038.
    \77\ 49 CFR 571.122, S5.1.5, Other requirements.
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IV. Specific Performance Test Improvements to FMVSS No. 122

    Here, we discuss the proposed specific test procedures and
performance criteria improvements to FMVSS No. 122, any comments
received on these proposed improvements, and the agency's response to
those comments. Where no comments were received on a proposed test
procedure or performance criteria, or a certain aspect of those
requirements, NHTSA has generally adopted those proposals in accordance
with the rationale detailed in the NPRM. Although this final rule
states as such for each amendment, we generally will not repeat the
rationale and justification for aspects of the proposal that did not
receive comment. We refer readers to

the NPRM for the basis for those amendments.\78\
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    \78\ See FMVSS No. 122 NPRM, 73 FR at 54023-54027.
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A. Dry Stop Test--Single Brake Control Actuated

    This final rule is adopting the proposed provision for a dry stop
test with single brake control that is based on UNECE Regulation No. 78
and JSS 12-61 tests.\79\ Currently, FMVSS No. 122 does not have a
requirement that tests each brake system separately except for tests
with the brakes in a pre-burnished condition. All other tests with the
brake system fully operational require front and rear brake application
simultaneously. In the main FMVSS No. 122 dry stop test with both brake
controls actuated simultaneously, the test rider judges how to
apportion the actuation force to the front and rear brakes. This may
give less repeatable test results or allow the test rider to compensate
for a ``weak'' brake. As such, an additional test specifying that each
brake be tested individually will improve FMVSS No. 122.
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    \79\ See FMVSS No. 122 NPRM, 73 FR at 54027.
---------------------------------------------------------------------------

    The purpose of a dry stop test requirement with the separate
actuation of each brake control is to ensure a minimum level of
motorcycle braking performance on a dry road surface for each
independent brake system. Current FMVSS No. 122 performance
requirements are quite different as they specify motorcycles be tested
in what is effectively the lightly-loaded condition,\80\ and with all
brake controls actuated simultaneously. The exception is the pre-
burnish test requirements, which specify that each independently
actuated service brake system must be capable of stopping the
motorcycle (in effectively the lightly-loaded condition) within
specified stopping distances.
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    \80\ As mentioned above, current FMVSS No. 122 specifies that
performance requirements must be met when the ``motorcycle weight is
unloaded vehicle weight plus 200 pounds.'' 49 CFR 571.122, S6.1.
``Unloaded vehicle weight'' is defined under 49 CFR 571.3(b) to mean
``the weight of a vehicle with maximum capacity of all fluids
necessary for operation of the vehicle, but without cargo,
occupants, or accessories that are ordinarily removed from the
vehicle when they are not in use.'' This current FMVSS No. 122 test
mass condition is effectively equivalent to the mass condition
``lightly loaded'' in the proposed rule. Lightly loaded means the
sum of unladen vehicle mass (mass of the vehicle with bodywork and
all factory fitted equipment, and fuel tanks filled to at least 90
percent) and driver mass ``plus 15 kg for test equipment, or the
laden condition, whichever is less.'' 73 FR 54020, 54037 (proposed
FMVSS No. 122 S4, Definitions).
---------------------------------------------------------------------------

    The MIC and Harley-Davidson each pointed out in their comments that
the proposed specification of brake actuation force for the single
brake control actuated dry stop test in the NPRM regulatory text
appeared to be missing a force value for motorcycle category 3-4
(proposed paragraph S6.3.2(d)(2)(ii)).\81\ They pointed out that this
test procedure specification should read ``<= 500 N for motorcycle
category 3-4'' instead of ``<= for motorcycle category 3-4.'' No other
commenter mentioned this proposed test procedure.
---------------------------------------------------------------------------

    \81\ MIC Comments, Docket No. NHTSA-2008-0150-0017.1 at 3;
Harley-Davidson Comments, Docket No. NHTSA-2008-0150-0012 at 5.
---------------------------------------------------------------------------

    Agency Response: We agree with the commenters that the force value
was missing from the paragraph S6.3.2(d)(2)(ii) test procedure
specification. Consistent with the GTR, we have revised this paragraph
to specify a foot control brake actuation force of 500 N for category
3-4 motorcycles. Since no commenter disagreed with the adoption of the
proposed single brake control-actuated dry stop test, this final rule
includes the dry stop test with single brake control based on UNECE
Regulation No. 78/JSS 12-61 requirements, for the reasons explained in
the NPRM. Unlike present UNECE/JSS standards, the requirement will
specify only stopping distance as the measurement criterion and will
not include MFDD as an optional criterion. When NHTSA conducts
compliance testing, we will use stopping distance as the performance
measure.

B. Dry Stop Test--All Service Brake Controls Actuated

    This final rule is also adopting the proposed provision to test the
service brakes with both brake controls applied simultaneously, which
is very similar to the current FMVSS No. 122 dry stop test with both
brake controls applied simultaneously. The purpose of this test with
all service brake controls actuated is to evaluate the full braking
performance of motorcycles from a speed of 100 km/h with both front and
rear brakes applied simultaneously. These test parameters are relevant
since they represent the typical operating conditions of a motorcycle
with a single rider traveling at highway speeds. In addition, testing
in the lightly loaded condition with a full brake application helps to
evaluate motorcycle stability during braking. Since we did not receive
comments on this performance test, this final rule is adopting this
test procedure and performance criteria as proposed, for the reasons
explained in the NPRM.

C. High-Speed Test

    We are also adopting the proposed high-speed test, for the reasons
largely explained in the NPRM. The purpose of the high-speed test is to
evaluate the full braking performance of the motorcycle from a high
speed and with both front and rear brakes applied simultaneously. The
test is performed from a speed of 160 km/h or 0.8 of the vehicle's
maximum speed (Vmax), whichever is less.
    Based on the NHTSA/Transport Canada Review of Motorcycle Brake
Standards,\82\ it was determined during development of the GTR that 100
mph (160 km/h) or 0.8 Vmax is adequate for a high speed effectiveness
test since the benefits of testing from higher speeds do not warrant
the potential hazard to which the test rider is exposed. Consistent
with the GTR, the high-speed test procedure specified in this final
rule limits the test speed to 160 km/h to address test facility
limitations and safety concerns. As proposed, this final rule also
specifies that the high speed test be conducted with the motorcycle
engine connected, i.e., with the clutch engaged, and the transmission
in the highest gear, which has the effect of enhancing motorcycle
stability during braking from high speeds.
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    \82\ See Docket Nos. NHTSA-2008-0150-0005.1, NHTSA-2008-0150-
0006.1.
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    The MIC noted a typographical error in the proposed regulatory text
for the high-speed test in the specification for the initial brake
temperature measurement.\83\ The MIC correctly noted that, consistent
with the GTR, the initial brake temperature should be specified as ``>=
55 [deg]C and <= 100 [deg]C.''
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    \83\ MIC Comments, Docket No. NHTSA-2008-0150-0017.1 at 3.
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    Agency Response: We agree with the MIC that there was a
typographical error in the proposed initial brake temperature test
condition in the high-speed test procedure regulatory text, and that it
should read as quoted above. The proposed regulatory text used two
greater than or equal to symbols, instead of one greater than or equal
to symbol, and one less than or equal to symbol. For the reasons
explained above and in the NPRM, we are adopting the high-speed test
procedure and performance criteria as proposed, with the correction
noted above.

D. Wet Brake Test

    This final rule is also adopting the proposed wet brake test
provision, which differs from the current FMVSS No. 122 wet brake test
in that instead of submerging the brake system in water and then
testing the brakes, the water is sprayed directly onto the brakes
during the test. This procedure is based on UNECE Regulation No. 78 and
JSS 12-61, which the reviews of motorcycle

brake standards found to be more stringent than current FMVSS No. 122.
Accordingly, we believe that motorcycle brake safety will be enhanced
as a result of this change in wet brake test procedure. The purpose of
the wet brake test is to ensure a minimum level of braking performance
when the motorcycle is ridden in heavy rain conditions.
    The wet brake performance evaluation specified in this final rule
begins with a baseline test where each brake is tested separately and
is required to decelerate a laden motorcycle at a specified rate, using
the conditions of the dry stop test--single brake control actuated. For
comparison, the same test is then repeated, but with a constant spray
of water to wet the brakes. The difference in performance is evaluated
immediately after the application of the respective brake, to ensure a
minimum rise in deceleration performance with wet brakes. In addition,
a drying brake can sometimes result in an excessively high pad friction
leading to motorcycle instability and wheel lock; therefore a check for
this ``over recovery'' is also included. Since we did not receive
comments on this performance test, this final rule is adopting this
test procedure and performance criteria as proposed, for the reasons
explained here and in the NPRM.

E. Heat Fade Test

    We are also adopting the proposed heat fade test provision, which
is based on the UNECE Regulation No. 78 and JSS 12-61 fade test. As
explained in the NPRM, the results from both stringency studies
indicated that this fade test is more stringent than the current FMVSS
No. 122 fade test. The heat fade test ensures that a minimum level of
braking performance is maintained after numerous consecutive brake
applications. In terms of real world conditions, this could be akin to
frequent braking while driving in a busy suburban area or on a downhill
gradient.
    The adopted heat fade test requires that the brakes be tested
separately, with the motorcycle loaded to its maximum mass capacity.
The test begins with a baseline test with an IBT between 55 [deg]C and
100 [deg]C, which provides the benchmark for performance comparison and
evaluation of the heated brakes. This is followed by 10 consecutive
fade stops with the purpose of building heat within the brakes. The
final performance test occurs with one stop immediately following the
10 fade stops. To evaluate brake fade performance, the procedure
compares the stopping distance for the same brake pedal and lever
actuation forces as used in the baseline test.
    Minor adjustments were made to the UNECE Regulation No. 78 and JSS
12-61 fade test. The text for the performance criteria was revised to
use the average brake control force from the baseline test, calculated
from the measured values between 80 percent and 10 percent of the
specified vehicle test speed. The brake heating procedure was also made
more objective. UNECE Regulation No. 78 presently requires that the
motorcycle decelerate to the lesser of 3 meters per second squared (m/s
\2\) or the maximum achievable deceleration rate with that brake
control. For the purposes of the GTR, the latter performance
requirement is made more objective by specifying that, at a minimum,
the motorcycle must meet the deceleration rate for the dry stop test--
single brake control actuated, as noted in Table 2 of the regulatory
text. As noted above in section IIIB, this is different from MFDD.
    Since we did not receive comments on this performance test, this
final rule is adopting the heat fade test procedure and performance
criteria as proposed, for the reasons explained here and in the NPRM.

F. Parking Brake System Test

    This final rule is adopting the proposed parking brake test, which
will improve upon the current FMVSS No. 122 parking brake system test
by specifying a more stringent loading condition. The purpose of the
parking brake system performance requirement is to ensure that
motorcycles required to be equipped with parking brakes can remain
stationary without rolling away when parked on an incline.
    Consistent with the GTR, the test adopted in this final rule
specifies that the parking brake system be capable of holding the
motorcycle stationary for five minutes when tested in the laden
condition (i.e., the maximum weight limit specified by the
manufacturer) on an 18 percent grade, in both the forward and reverse
directions (to the limit of traction of the braked wheels). In
addition, like current FMVSS No. 122, the amended test procedure
requires that the parking brake system be designed to retain engagement
solely by mechanical means.
    Honda noted that, in adopting section 4.8.3 of the GTR regulatory
language on parking brakes, NHTSA's proposal parenthetically added ``to
the limits of traction of the braked wheels'' to the performance
requirements in paragraph S6.8.3 of the proposed FMVSS No. 122
regulatory text.\84\ Honda suggested that this additional language
would be more appropriately included in the parking brake test
procedure, or section S6.8.2 of the regulatory text. The MIC made a
similar comment.\85\
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    \84\ Honda Comments, Docket No. NHTSA-2008-0150-0018.1 at 2-3.
    \85\ MIC Comments, Docket No. NHTSA-2008-0150-0017.1 at 2.
---------------------------------------------------------------------------

    Agency Response: We agree that the added text would be more
appropriately included in S6.8.2 rather than paragraph S6.8.3, as in
the proposal. The regulatory text of the final rule reflects this
change with the insertion of a new subparagraph under S6.8.2 (test
conditions and procedures for parking brake system test) which states:
``The motorcycle must remain stationary to the limits of traction of
the braked wheels.'' For the reasons explained above and in the NPRM,
we are adopting the parking brake system test procedure and performance
criteria as proposed, with the minor rearrangement of language noted
here.

G. Antilock Brake System (ABS) Performance Test

    Today's final rule does not require ABS but does contain ABS
minimum performance requirements for motorcycles that are voluntarily
equipped with this type of brake system. The purpose of the specified
ABS test procedures is to assess the stability and stopping performance
of a motorcycle with the ABS functioning.
    These new tests, adopted from the GTR, include stopping distance
performance requirements on high and low friction surfaces, wheel lock
tests on high and low friction surfaces, and wheel lock tests for high
to low friction and low to high friction surface transitions. In
addition, the new performance requirements include an ABS failed
systems performance test. Current FMVSS No. 122 does not include any
ABS-specific performance requirements.
    In the NPRM, NHTSA explained that we believe the ABS definition
developed for the GTR is not as comprehensive as NHTSA's ABS definition
which appears in three other Federal motor vehicle safety standards:
FMVSS No. 105, Hydraulic and Electric Brake Systems; FMVSS No. 121, Air
Brake Systems; and FMVSS No. 135, Light Vehicle Brake Systems. The two
definitions are presented below:
     GTR Definition: Antilock brake system or ABS means a
system which senses wheel slip and automatically modulates the pressure
producing the braking forces at the wheel(s) to limit the degree of
wheel slip.

     The current FMVSS Definition: Antilock brake system or ABS
means a portion of a service brake system that automatically controls
the degree of rotational wheel slip during braking by:
    (1) Sensing the rate of angular rotation of the wheels;
    (2) Transmitting signals regarding the rate of wheel angular
rotation to one or more controlling devices which interpret those
signals and generate responsive controlling output signals; and
    (3) Transmitting those controlling signals to one or more
modulators which adjust brake actuating forces in response to those
signals.
    The NPRM explained that we believe both definitions can be
interpreted to mean the same thing. The NPRM sought comment on the
proposed GTR definition and on the ABS definition used in the other
braking standards. Since we did not receive comment on the definition
of ABS, we are adopting the GTR definition, as proposed. However, we
continue to believe that this is consistent with other FMVSSs, as both
definitions above can be interpreted to mean the same thing.
    During the development of the GTR, each of the ABS performance
tests and their corresponding requirements was reviewed to assess their
appropriateness for the proposed motorcycle brake system GTR.\86\ This
analysis is discussed in the NPRM and will not be repeated here except
to the extent that it relates to comments received on the proposed ABS
test procedures and performance criteria. Commenters were generally
supportive of the adoption of the proposed ABS test procedures.
Therefore, with the exception of the minor changes discussed below, we
are adopting the ABS test procedures and performance criteria for the
reasons explained here and in the NPRM.\87\

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    \86\ See Docket No. NHTSA-2008-0150-0009.1.
    \87\ See FMVSS No. 122 NPRM, 73 FR at 54030-54032.
---------------------------------------------------------------------------

1. Low Friction Surface for ABS Testing
    The proposed ABS test procedures included a wheel lock check and
stopping distance performance requirement on a low friction surface,
and wheel lock checks on a high-to-low and low-to-high surface
transitions.\88\ Harley-Davidson commented that the test tracks it
utilizes to certify ABS systems rely upon water delivery to reduce the
surface friction to the required level for the low friction surface
tests.\89\ Harley-Davidson expressed concern that the proposed
regulatory text stated in paragraph S<IP_ADDRESS> that the ASTM procedure to
measure PBC be conducted ``without water delivery.'' Harley-Davidson
stated that modifications needed to create a dry low friction surface
would be costly and requested that NHTSA permit use of a wet surface as
an alternative means of achieving the low friction surface test
conditions.
---------------------------------------------------------------------------

    \88\ See FMVSS No. 122 NPRM, 73 FR at 54042.
    \89\ Harley-Davidson Comments, Docket No. NHTSA-2008-0150-0012
at 3.
---------------------------------------------------------------------------

    Agency Response: It was not our intention to prevent use of a
wetted surface for the low friction portion of the ABS test sequence.
Paragraph S<IP_ADDRESS> describes how the PBC of a dry surface is measured
using the ASTM procedure but did not consider the need for measuring a
wetted surface. We have deleted the phrase ``without water delivery''
from the S<IP_ADDRESS> test procedure to allow for the use of either wet or
dry low friction surfaces. We note that the description of a low
friction surface (S<IP_ADDRESS>) states that it must be a ``clean and level
surface,'' which allows it to be wetted, as compared with the
description of the high friction surface (S<IP_ADDRESS>) which must be a
``clean, dry and level surface''.
2. Wheel Lock
    Harley-Davidson pointed out in its comments that various
performance requirements in the proposed ABS tests section (S6.9)
prohibit wheel lock, but paragraph S6.9.1(d) specifies that wheel lock
is allowed ``as long as the stability of the vehicle is not affected to
the extent that it requires the operator to release the control or
causes the vehicle to pass outside the test lane.'' \90\ Harley-
Davidson commented that it is unclear if the same language permitting