Document ID: NHTSA-2010-0021-0001
Agency: nhtsa
Document Type: Rule
Title: Federal Motor Vehicle Safety Standards: Electric-Powered Vehicles; Electrolyte Spillage and Electrical Shock Protection
Posted Date: 2010-06-14T04:00Z

[Federal Register: June 14, 2010 (Volume 75, Number 113)]
[Rules and Regulations]               
[Page 33515-33531]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr14jn10-10]                         

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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Part 571

[Docket No. NHTSA-2010-0021]
RIN 2127-AK05

 
Federal Motor Vehicle Safety Standards; Electric-Powered 
Vehicles; Electrolyte Spillage and Electrical Shock Protection

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

ACTION: Final rule.

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SUMMARY: In response to a petition for rulemaking from the Alliance of 
Automobile Manufacturers, NHTSA is issuing this final rule to 
facilitate the development and introduction of fuel cell vehicles, a 
type of electric-powered vehicle, and the next generation of hybrid and 
battery electric powered vehicles. It does so by revising the agency's 
standard regulating electrolyte spillage and electrical shock 
protection for electric-powered vehicles to align it more closely with 
the April 2005 version of the Society of Automotive Engineers (SAE) 
Recommended Practice for Electric and Hybrid Electric Vehicle Battery 
Systems Crash Integrity Testing (SAE J1766).
    The standard currently requires manufacturers to design their 
vehicles so that, in the event of a crash, a vehicle's propulsion 
battery system will be electrically isolated from the vehicle's 
electricity-conducting structure. As amended, this rule provides 
greater flexibility, requiring manufacturers to design their 
electrically powered vehicles so that, in the event of a crash, the 
electrical energy storage, conversion, and traction systems are either 
electrically isolated from the vehicle's chassis or their voltage is 
below specified levels considered safe from electric shock hazards.
    Since the physiological impacts of direct current (DC) are less 
than those of alternating current (AC), this rule specifies lower 
electrical isolation requirements for certain DC components than for AC 
components. The current standard does not recognize the difference in 
safety risk between DC and AC components, requiring both types of 
components to meet the same requirements. As requested by the 
petitioners, this final rule specifies the following electrical 
isolation requirements: 500 ohms/volt for AC and DC high voltage 
sources and 100 ohms/volt for DC high voltage sources with continuous 
monitoring of electrical isolation.

DATES: Effective Date: This rule is effective September 1, 2011, with 
optional early compliance.

ADDRESSES: Petitions: Petitions for reconsideration should refer to the 
docket number above and be submitted to: Administrator, National 
Highway Traffic Safety Administration, 1200 New Jersey Avenue, SE., 
Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: For technical issues, you may contact 
Mr. Charles Hott, Office of Rulemaking, by telephone at (202) 366-0247, 
or by fax at (202) 493-2990. For legal issues, you may contact Ms. 
Rebecca Yoon, Office of Chief Counsel, by telephone at (202) 366-2992, 
or by fax at (202) 366-3820. You may send mail to these officials at 
the National Highway Traffic Safety Administration, U.S. Department of 
Transportation, 1200 New Jersey Avenue, SE., Washington, DC 20590.

SUPPLEMENTARY INFORMATION:
I. Background
    A. Standard No. 305 and the Alliance Petition for Rulemaking To 
Upgrade It
    B. The NPRM
    C. Summary of Public Comments Received
    D. How The Final Rule Differs From the NPRM
II. Public Comments on the NPRM and Agency Responses
    A. Multiple Options for Providing Electrical Safety in Electric-
Powered Vehicles
    1. Electrical Isolation
    (a) Requirements for Electrical Isolation of AC and DC Systems
    (b) Continuous Monitoring Requirement for Electrical Isolation
    (c) Timing of Measurements for Electrical Isolation
    2. Voltage Level
    3. Energy Limit (0.2 Joules)
    B. Other Issues Relating to the Electrical Isolation Requirement
    C. Comments Regarding Test Procedures
    D. Regulatory Text Wording
    E. Physical Barriers as an Additional Option for Providing 
Electrical Safety
    F. Effective Date
    G. Hyundai Request for Interpretation on S5.2 Battery Retention
    H. Preemption
III. Rulemaking Analyses and Notices
IV. Regulatory Text

I. Background

A. Standard No. 305 and the Alliance Petition for Rulemaking To Upgrade 
It

    The purpose of Federal Motor Vehicle Safety Standard (FMVSS) No. 
305, Electric-Powered Vehicles: Electrolyte Spillage and Electrical 
Shock Protection, is to reduce deaths and

[[Page 33516]]

injuries during a crash which occur because of electrolyte spillage 
from propulsion batteries, intrusion of propulsion battery system 
components into the occupant compartment, and electric shock. FMVSS No. 
305 currently does so in part by requiring electric-powered vehicles to 
limit electrolyte spillage and retain batteries. To promote electrical 
safety, it specifies a single criterion, i.e., maintaining electrical 
isolation between the vehicle's electrical conducting structure and 
high voltage battery system. In order to protect vehicle occupants, 
rescue workers, or others who may come in contact with the vehicle 
after a crash from electrical shock hazards, FMVSS No. 305 currently 
requires an electrical isolation of 500 ohms/volt between the 
propulsion batteries and the vehicle's electrical conducting structure 
after the frontal, side, and rear crash tests of FMVSS Nos. 208, 
Occupant Crash Protection, 214, Side Impact Protection, and 301, Fuel 
System Integrity, respectively. The standard currently does not require 
electrical isolation between other potential high voltage sources that 
may cause a shock hazard, such as high voltage propulsion motors, fuel 
cells, inverters, and converters. Also, the standard's 500 ohms/volt 
isolation requirement does not distinguish between AC and DC systems, 
despite a difference in human tolerance for the two types of electrical 
current.
    FMVSS No. 305 was originally drafted based on a voluntary consensus 
standard, the Society of Automotive Engineers (SAE) Recommended 
Practice for Electric and Hybrid Electric Vehicle Battery Systems Crash 
Integrity Testing, SAE J1766 (1998 version). SAE J1766 was updated in 
April 2005 to accommodate current fuel cell vehicle (FCV) designs that 
were deemed by their manufacturers to be electrically ``safe,'' but 
that were unable to meet existing electrical isolation requirements. 
Their inability stemmed from the fact that the liquid coolant needed in 
those FCV designs to cool the fuel cells tended to increase in 
conductivity over time, which resulted in the loss of electrical 
isolation of high voltage components in contact with it and thus 
prevented those vehicles from maintaining the 500 ohms/volt electrical 
isolation from the vehicles' electrical conducting structure.
    The updated version of SAE J1766 differs from the previous version 
in two main ways. Instead of only one criterion for promoting 
electrical safety, it specifies three different alternative criteria: 
electrical isolation, low voltage, and low energy. It also specifies a 
revised isolation requirement that distinguishes between AC and certain 
DC systems.
    The Alliance of Automobile Manufacturers (``the Alliance'') 
petitioned NHTSA to conduct a rulemaking to amend the requirements of 
FMVSS No. 305 in order to bring the standard into alignment with the 
updated version of SAE J1766. The Alliance argued that such upgrades to 
FMVSS No. 305 were necessary so that continued development of FCVs 
could proceed without hindrance.

B. The NPRM

    On October 9, 2007, NHTSA published the Notice of Proposed 
Rulemaking (NPRM) to upgrade FMVSS No. 305, mostly in line with the 
revised SAE J1766.\1\ The highlights of the NPRM were:
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    \1\ 72 FR 57261 (Oct. 9, 2007). The NPRM and comments on it can 
be found in Docket No. NHTSA-2007-28517. That docket can be accessed 
online at http://www.regulations.gov.
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     Distinguishing between electrical isolation values for DC 
and AC currents based on relative risk of harm to accommodate fuel cell 
vehicles and setting the value for DC high voltage systems at 125 ohms/
volt.
     Broadening the requirement in S5.3 from ``electrical 
isolation'' alone to ``electrical safety,'' and permit achieving 
compliance either through electrical isolation or through a low voltage 
option under which the post-crash voltage of the source must be less 
than or equal to 60 volts of direct current (VDC) or 30 volts of 
alternating current (VAC).
     Adding a definition for ``high voltage source,'' and 
applying electrical safety requirements to any high voltage source, 
instead of to only the propulsion battery.
     Harmonizing the rear moving barrier impact test conditions 
of S6.2 and S7.4 of FMVSS No. 305 with the revised FMVSS No. 301.

C. Summary of Public Comments Received

    Most of the comments received by the agency were from vehicle 
manufacturers. The Alliance of Automobile Manufacturers (Alliance) and 
the Association of International Automobile Manufacturers (AIAM) filed 
comments jointly (this final rule refers to these as the ``Alliance/
AIAM comments''). The Alliance also filed supplemental comments on June 
15, 2009. Four vehicle manufacturers submitted comments individually: 
Nissan North America, Inc. (``Nissan''), Porsche Cars North America, 
Inc. (``Porsche''), Toyota Motor Corporation (``Toyota''), and Honda 
Motor Co., Ltd. (``Honda''). The American Association of Justice 
(``AAJ,'' formerly known as the Association of Trial Lawyers of America 
or ATLA) also submitted comments on the NPRM.
    In summary, the vehicle manufacturers generally requested that the 
agency conform FMVSS No. 305 more closely to the revised SAE J1766. 
Commenters disagreed with the proposed level of electrical isolation 
for DC high voltage systems as unnecessarily stringent, and with the 
omission of proposed regulatory text adopting SAE J1766's monitoring 
requirement. Regarding the alternative compliance options for providing 
electrical safety, commenters expressed support for the addition of an 
option limiting residual electrical energy, as well as an explicit low 
voltage option. Commenters also raised issues regarding test 
procedures, including requesting a provision expressly addressing the 
use of a megohmmeter for electrical isolation measurement. Commenters 
also suggested changes to the regulatory text, many of which were 
fairly editorial in nature.
    The AAJ objected to the agency's brief discussion in the NPRM of 
the law relating to the circumstances under which State tort law might 
be found by a court to be impliedly preempted. Interpreting this 
discussion as an assertion of implied preemption of state tort law in 
connection with this particular rulemaking, the AAJ objected to the 
discussion just as it has objected to similar discussions in other 
NHTSA rulemaking actions over the last several years.

D. How the Final Rule Differs From the NPRM

    The following points highlight the key differences between the 
requirements of the final rule and the proposed requirements in the 
NPRM:
     S5.3 has been revised to require 100 ohms/volt electrical 
isolation for DC systems with continuous monitoring of electrical 
isolation during vehicle operation, rather than the more conservative 
value of 125 ohms/volt proposed in the NPRM, based on new analysis of 
available data.
     S5.3 has been revised to include an explicit low voltage 
option for providing electrical safety. A new paragraph, S7.7, has been 
added that details a procedure for voltage measurement to determine if 
the voltage source is of low voltage.
     A new paragraph, S5.4, has been added to specify 
requirements for vehicles equipped with electrical isolation monitoring 
systems. A new paragraph, S8, has been added that details a test 
procedure to confirm the

[[Page 33517]]

functioning of the isolation monitoring system.
     S3 and S4 now clarify that ``working voltage'' is used (as 
opposed to actual voltage only) to identify a vehicle as subject to 
FMVSS No. 305 and to identify a source as ``high voltage.''
     S7.6.6 and S7.6.7 are modified to specify that the 
electrical isolation of a high voltage source in ohms/volt is obtained 
by dividing the electrical isolation resistance of the high voltage 
source by its working voltage.
     Some definitions of terms used in FMVSS No. 305 have been 
added or altered for greater clarity.
     Minor editorial corrections have been made to other parts 
of the regulatory text and to Figures 1 through 5.
    The final rule also notes that there has been a fundamental 
misunderstanding of its preemption discussions and emphasizes that 
neither in the FMVSS No. 305 NPRM nor in any of the other actions 
identified by the AAJ did this agency assert implied preemption.

II. Public Comments on the NPRM and Agency Responses

A. Multiple Options for Providing Electrical Safety in Electric-Powered 
Vehicles

    As discussed above, the NPRM proposed to expand the ways in which 
electrical safety may be provided under FMVSS No. 305, based on the 
changes to SAE J1766 to accommodate current FCV designs. This was 
accomplished in part by proposing a definition for a new term, 
``electrical safety,'' (which included ``electrical isolation''), and 
separate requirements for electrical isolation of AC systems and DC 
systems. It did not include some methods of providing ``electrical 
safety'' that the SAE definition does, namely, an electrical energy 
option requiring that there be less than 0.2 Joules of energy, and a 
method of using low voltage readings directly as a means of compliance. 
The NPRM also proposed an isolation value of 125 ohms/volt for DC 
systems, instead of the 100 ohms/volt with continuous monitoring 
contained in SAE J1766. Comments received on these issues from vehicle 
manufacturers primarily took exception to the agency's departure from 
the SAE J1766 language.
1. Electrical Isolation
    The NPRM proposed 125 ohms/volt isolation for DC systems, a value 
more conservative than the 100 ohms/volt contained in SAE J1766 and 
recommended by the petitioner. We proposed 125 ohms/volt instead of 100 
ohms/volt because our analysis indicated that limiting DC to 125 ohms/
volt offered the same level of protection against shock hazards as 
limiting AC to 500 ohms/volt. We used graphs from International 
Electrotechnical Commission (IEC) Technical Reports,\2\ available as 
part of the technical support document for this rule which is located 
in the docket, showing physiological effects resulting from different 
durations of current flow, and made a simple comparison. Based on the 
IEC report, the human body can withstand up to four times the amount of 
DC as AC. The 500 ohms/volt requirement in FMVSS No. 305 translates to 
2 milliamps of AC.\3\ The flow of this amount of AC through the human 
body may result in perception of the current and likely involuntary 
muscular contractions, but usually with no harmful physiological 
effects, and is considered to be safe. Based on the ratio of 4 between 
DC and AC current, 2 milliamps (mA) of AC (that is considered to be 
safe) corresponds to 8 mA of DC (that is also considered to be safe for 
the human body).\4\ The agency also did not propose monitoring of 
isolation, but noted that the petitioner's request for an isolation 
value of 100 ohms/volt for DC was coupled with a request for continuous 
monitoring.
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    \2\ IEC TS 60479-1 and TS 60479-2 Effects of Current on Human 
Beings and Livestock--Part 1: General Aspects, Part 2: Special 
Aspects, 2005-07, Reference Nos. CEI/IEC/TS 60479-1:2005 and CEI/
IEC/TS 60479-2:2005. These IEC documents are available for public 
viewing in the Office of Crashworthiness Standards, National Highway 
Traffic Safety Administration, West Building, 1200 New Jersey 
Avenue, SE., Washington, DC 20590, or available for purchase at 
http://webstore.iec.ch/webstore/webstore.nsf/artnum/034455 (last 
accessed June 19, 2009).
    \3\ 500 ohms/volt = 1/I, where I is the current in amperes (A). 
Then I = 1/500 = 0.002 A or 2 mA.
    \4\ 8 mA = 0.008 A = V/R (current = voltage/resistance). 1/0.008 
= 125 ohms/volt. See 72 FR 57262 (Oct. 9, 2007) for a fuller 
discussion of this issue.
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(a) Requirements for Electrical Isolation of AC and DC Systems
    The Alliance/AIAM comments disagreed with the agency's proposal to 
adopt an isolation requirement of 125 ohms/volt instead of 100 ohms/
volt for DC high voltage systems. The Alliance/AIAM argued that the IEC 
technical report relied upon by the agency defines the equivalence 
factor of four (as in, the human body can withstand up to four times 
the amount of DC as AC) only in terms of ventricular fibrillation, and 
that there is ``no technical justification'' for applying that 
particular equivalence factor to levels of current that would cause 
physiological responses less serious than ventricular fibrillation. The 
Alliance/AIAM stated that a representative from General Motors 
consulted with the IEC Working Group responsible for IEC 479-1, and 
that the Working Group ``declined to identify a precise level of DC 
isolation that would equate to 500 ohms/volt for AC,'' stating that the 
group would only say that ``a point in the mid-range of AC zone 2 is 
approximately equivalent to a point in the mid-range of DC zone 2.''
    The Alliance/AIAM argued that, instead of trying to ascertain a 
level of DC isolation that is precisely equivalent to 500 ohms/volt AC 
isolation, the agency should simply ``adopt a level of DC isolation 
that is practicable and meets the need of motor vehicle safety.'' The 
Alliance/AIAM stated that 100 ohms/volt DC met those criteria, because 
it is located in the mid-range of zone 2 and thus ``far removed from 
the potentially life-threatening effects associated with zone 4 
currents and durations.'' The Alliance/AIAM also stated that 100 ohms/
volt DC was even safer compared to 500 ohms/volt AC, according to 
revised IEC charts (the IEC report on which the agency relied was 
updated in July 2005, after the petition for rulemaking was submitted 
to NHTSA).\5\
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    \5\ Specifically, the Alliance/AIAM argued that if the agency's 
concern is the distance of the separation of the isolation value 
from the nearest point of zone 3 (on the charts), 100 ohms/volt DC 
continues to provide 15 milliamps of separation from the nearest 
point of DC zone 3, while 500 ohms/volt AC provides only 3 milliamps 
of separation from the nearest point of AC zone 3 (but provided 8 
milliamps of separation before), due to revision of the charts.
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    The Alliance/AIAM also argued that 100 ohms/volt would be a good 
choice for a DC isolation value for harmonization reasons, because it 
``is specified in the relevant SAE document, ISO document, Japanese 
regulation, and draft ECE regulation.''
    Agency response:
    The agency has re-analyzed the appropriate value for DC isolation 
based on the charts provided in the IEC reports. Our new analysis 
indicates that an isolation value of 100 ohms/volt for DC represents an 
appropriate level of isolation.
    We agree that given the available data and the differing natures of 
the two kinds of electrical current, no one can determine exactly what 
DC isolation value would be perfectly equivalent to 500 ohms/volt AC. 
However, this does not alleviate the agency's responsibility to make 
the best possible estimate. We cannot simply choose, as the Alliance/
AIAM would have us do, an isolation limit for DC that ``is practicable 
and meets the need of motor vehicle safety.'' These are necessary 
conditions for every

[[Page 33518]]

agency rule, but they do not guarantee that such a limit for DC 
isolation would offer an equivalent level of safety as the limit for AC 
isolation. In light of the comments submitted, the agency took a fresh 
look at what level of DC isolation would offer an equivalent level of 
safety. A fuller explanation of the agency's analysis for this final 
rule is available in the docket for this rulemaking.
    We used the Alliance/AIAM reference to the IEC Working Group 
statement that ``a point in the mid-range of AC zone 2 is approximately 
equivalent to a point in the mid-range of DC zone 2'' as a starting 
point for our re-analysis. By definition, ``zone 2'' of both the AC and 
DC charts represents very similar physiological response to electrical 
current.\6\ Since zones AC-2 and DC-2 represent such similar 
physiological responses, the agency assumed, for purposes of analysis, 
that the responses at the upper and lower boundaries of the zones are 
the same, which allowed us to find appropriate points in the ``mid-
range'' of the zones to compare for equivalence. The upper and lower 
boundary of zone 2 at 10 second shock duration for AC current is at 5 
and 0.5 mA, respectively, and that for DC current is at 26 and 2 mA, 
respectively.\7\ Assuming a logarithmic relationship between zone AC-2 
and zone DC-2, the agency interpolated linearly between these upper and 
lower boundaries of each zone at 10 second shock duration. The 
resulting relationship between AC and DC levels in Zone 2 at 10 second 
shock duration is given by log(DC current in mA) = 1.114 * log(AC 
current mA) + 0.636. Given that an electrical isolation of 500 ohms/
volt AC corresponds to 2 mA AC current, and using the mapping between 
AC and DC current levels in zone 2, the agency determined that the DC 
current level corresponding to 2 mA of AC current is 9.37 mA DC, which 
translates to 107 ohms/volt DC.\8\ Therefore, the agency's best 
estimate for purposes of this final rule was reduced from 125 to 107 
ohms/volt DC as equivalent to 500 ohms/volt AC. Since the 107 ohms/volt 
isolation value is only slightly more conservative than the 100 ohms/
volt DC isolation value already contained in SAE J1766 and in several 
international standards, as mentioned by the commenters, we are 
comfortable that setting the DC electrical isolation value for the 
final rule at 100 ohms/volt will provide an equivalent level of safety 
to the 500 ohms/volt requirement for AC isolation.
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    \6\ Table 11 of IEC TS 60479-1 (2005) states that the 
physiological response for AC-2 is ``Perception and involuntary 
muscular contractions likely but usually no harmful electrical 
physiological effects,'' while Table 13 states that the 
physiological response for DC-2 is ``Involuntary muscular 
contractions likely especially when making, breaking or rapidly 
altering current flow but usually no harmful electrical 
physiological effects.''
    \7\ Based on Figures 20 and 22 of IEC TS 60479-1 (2005).
    \8\ 9.37 milliamps = 0.00937 Amps; 1/0.00937 = 107 ohms/volt.
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(b) Continuous Monitoring Requirement for Electrical Isolation
    The Alliance petition for rulemaking had argued that an isolation 
level of 100 ohms/volt for DC was safe when coupled with a requirement 
that isolation be continuously monitored. In the NPRM, NHTSA set the 
isolation level for DC at 125 ohms/volt without addressing the issue of 
continuous monitoring. The Alliance/AIAM comments to the NPRM stated 
that ``it would be preferable to the interests of safety and the 
viability of fuel cell vehicles for the agency to specify an isolation 
level of 100 ohms/volt [DC] with monitoring rather than an isolation 
level of 125 ohms/volt without monitoring.'' This is simply because, 
the commenters stated, ``electrical isolation declines in service, 
particularly DC isolation associated with a fuel cell stack,'' and 
while ``It is not difficult for a new fuel cell vehicle to exhibit * * 
* 100 ohms/volt isolation while in service,'' it ``is far more 
challenging * * * for a fuel cell vehicle to maintain 100 ohms/volt 
isolation while in service.'' The Alliance/AIAM expressed concern that 
setting an isolation requirement of 125 ohms/volt for DC with no 
continuous monitoring would not solve the problem of declining 
isolation over time.
    Agency response:
    Although NHTSA did not propose regulatory text for a requirement 
for continuous monitoring in the NPRM, we noted there that the 
petitioner's request for an isolation value of 100 ohms/volt for DC was 
coupled with a request for continuous monitoring. We have considered 
the issue further and we agree with the Alliance/AIAM comments stating 
that if the problem for fuel cell stacks is declining electrical 
isolation over time, solving the problem requires continuous monitoring 
of electrical isolation for high voltage DC sources that certify 
compliance by the 100 ohms/V electrical isolation option. We have 
specified this requirement in S5.3(a). In addition, the agency is 
adding a new paragraph, S5.4, to the regulatory text to specify that 
the electrical isolation monitoring system must continuously monitor 
the level of isolation, and display a warning to the driver if 
electrical isolation degrades to levels below the minimum required 
electrical isolation of 100 ohms/volt. We are also adding a test 
procedure to confirm the function of the electrical isolation 
monitoring system in S8.
(c) Timing of Measurements for Electrical Isolation
    Comments from the Alliance/AIAM and from Porsche expressed concern 
that the agency intended to require electrical isolation to be measured 
within 5 seconds after the vehicle crashes. The commenters requested 
that S5.3 be revised to include a sentence at the end of the paragraph 
stating that ``While electrical isolation can be provided `within 5 
seconds,' as it does not change over time, it is not necessary to 
actually measure it `within 5 seconds.' ''
    Agency response:
    The agency had no intent to require measurements to be taken within 
5 seconds, and S7 of the proposed regulatory text, which covers test 
conditions, clearly states that all measurements for calculating 
electrical isolation will be made after a minimum of 5 seconds 
immediately after the required crash tests. We do not believe that 
revising S5.3 to explain this further is necessary, but we are revising 
S7 in the final rule to clarify that we consider time zero for 
measurements to be when the test vehicle comes to rest, instead of 
``immediately after'' the tests. We believe that this addresses the 
concerns of the Alliance/AIAM and Porsche.
2. Voltage Level
    The existing FMVSS No. 305 essentially only allows manufacturers to 
prove that their vehicles are electrically safe by satisfying 
electrical isolation requirements, using an equation provided in FMVSS 
No. 305. As written, the equation includes dividing voltage 
measurements by one another, such that it is possible to end up with an 
undefined result if the voltage measurement that goes in the 
denominator is zero. An undefined result, theoretically, could prevent 
manufacturers from certifying that they meet the electrical isolation 
requirements.
    As noted above, in the NPRM, the agency did not explicitly provide 
for low voltage as a method of certifying electrical safety protection. 
We stated instead that ``We tentatively agree [that a voltage 
measurement of zero] would be evidence of electrical safety,'' and 
proposed to change the ``electrical isolation'' requirement of S5.3 to 
a broader one of ``electrical safety,'' and to require the specified 
electrical isolation between the chassis and the high voltage source. 
We believed that this

[[Page 33519]]

was sufficiently clear evidence of the agency's position that low 
voltage was an acceptable way to provide electrical safety.
    However, comments by the Alliance/AIAM argued that our statements 
were ``ambiguous,'' and reiterated their position that a reading of 
zero voltage after the crash test would make it impossible to certify 
vehicles under the electrical isolation requirements. The Alliance/AIAM 
stated that, as written, the approach in the NPRM would be 
``susceptible to misinterpretation in the context of varying and highly 
integrated vehicle designs. For example, a portion of the high voltage 
bus might meet the definition of high voltage source, but then have its 
voltage removed or dissipated during the specified crash tests.'' To 
avoid this, the commenters requested that S5.3 include a specific low 
voltage alternative. Porsche supported the Alliance/AIAM comments.
    Related to the request that NHTSA explicitly include a low voltage 
option for providing electrical safety, the Alliance/AIAM also 
requested that that the agency revise S7.6.3, the electrical isolation 
test procedure, to state that if the voltage is less than or equal to 
60 VDC or 30 VAC, the ``requirements are met and there is no need to 
proceed further.''
    Nissan, in addition to supporting the Alliance/AIAM comments, asked 
that the agency adopt an additional alternative for measuring voltage, 
``to mirror SAE Recommended Practice J1766.'' Specifically, ``in 
addition to measuring the voltage between the vehicle chassis and high 
voltage source,'' Nissan asked that the alternative option ``would 
measure Vb (after the crash test) at the positive and negative nodes, 
around the load, of the high voltage bus.'' Nissan also asked whether 
our intent in defining AC high voltage sources was to include sources 
that ``relate to the regenerative braking mode of the vehicle where the 
AC electric motor behaves as an energy source to recharge the high 
voltage battery.''
    Agency response:
    NHTSA agreed in the NPRM in principle to the concept that low 
voltage can provide electrical safety, and provided a letter of 
interpretation in October 2008 (between the publication of the NPRM and 
this final rule) confirming that, based on the information provided, 
the agency would consider a vehicle to have passed S5.3 of FMVSS No. 
305 when there is no measurable voltage following a crash test.\9\ 
Nevertheless, in order to alleviate the commenters' concern that 
manufacturers would still have to attempt to meet the electrical 
isolation requirement with an undefined answer to the equation in S7, 
the agency is adding the low voltage option to S5.3 and corresponding 
sections to the test procedure portion of the regulatory text at S7 and 
S7.7. Given that we are adding an explicit low voltage option to S5.3 
and low voltage test procedures to S7, we do not think it necessary to 
adopt the Alliance/AIAM recommendation that S7.6.3 be revised as 
requested.
---------------------------------------------------------------------------

    \9\ See Letter to Mr. Kenneth N. Weinstein, October 28, 2008. 
Available at Docket No. NHTSA-2008-0203-0003.
---------------------------------------------------------------------------

    As part of including a low voltage option in S5.3, the agency is 
requiring that voltage be measured across the terminals of the voltage 
source and between the voltage source and the vehicle chassis 
electrical conducting structure. The voltage source is considered to be 
low voltage if the voltage measured across its terminals and the 
voltage measured between the vehicle chassis electrical conducting 
structure and the positive and negative terminals of the source are all 
less or equal to 60 VDC or 30 VAC. Measuring the voltage across the 
terminals of the voltage source and between the terminals and the 
vehicle chassis ensures that all potential high voltage sources in both 
closed and open circuit conditions are captured. The agency believes 
that this will address Nissan's request that voltage be measured 
between the positive and negative nodes in addition to measuring the 
voltage between the high voltage source and the vehicle chassis.
    Regarding Nissan's request for clarification about whether 
regenerative braking motors would be considered a high voltage source, 
we would consider all sources which have a potential beyond 30 VAC to 
be AC high voltage sources, including sources relating to the 
regenerative braking mode of vehicles.
3. Energy Limit (0.2 Joules)
    The NPRM did not propose an energy limit option as a method of 
providing electrical safety, even though SAE J1766 includes one, 
because the agency did not believe that there was a clear safety need 
for this additional option. We did, however, seek comment on what 
safety need might exist, as well as on the practicality of measuring 
such a small amount of energy in a crash test environment.
    The Alliance/AIAM comments submitted in December 2007 argued that a 
low-energy alternative to providing electrical safety is necessary in 
FMVSS No. 305 because of the y-capacitors in a fuel cell system. As 
noted in the NPRM, a capacitor is like a battery in that it stores 
electrical energy and poses the same electrical safety hazards as a 
battery, except for electrolyte spillage. The December 2007 Alliance/
AIAM comments did not explain the function of x- and y-capacitors in 
fuel cells. In electrical power distribution, x-capacitors are placed 
across lines of high voltage differential, while y-capacitors are used 
in-line. A common application of x- and y-capacitors is filtering of 
electromagnetic or radio frequency interference, where they are 
directly connected to the AC power line. They may also be used to 
suppress electrical noise generated by motors and other components. We 
assume, for purposes of answering the Alliance/AIAM comment, that x- 
and y-capacitors are used in some kind of current filtering application 
in fuel cells.
    When coolant flows in a fuel cell, the voltage across individual y-
capacitors in the fuel cell becomes asymmetrical. The Alliance's 
supplemental June 2009 comments stated that this asymmetry in the 
voltage is, in fact, directly related to the coolant loop in a fuel 
cell, and that the asymmetry is likely to increase as coolant designs 
become more efficient. Thus, when x-capacitors in the fuel cell system 
discharge in the event of a crash, that discharge will leave a residual 
voltage (sometimes in excess of 60 VDC) on the y-capacitors. The 
Alliance's supplemental comments explained that as y-capacitor 
asymmetry increases in FCV designs with more efficient coolants, it 
could take as much as 10 or 20 seconds for the voltage to dissipate 
below the low voltage threshold of 60 VDC. However, the Alliance argued 
that this residual voltage on the y-capacitors would not pose a safety 
risk because the total energy levels would be very small. The Alliance, 
Toyota, and Ford told the agency in ex parte communications \10\ 
between the NPRM and the final rule that it would be difficult to 
provide electrical safety for certain high voltage sources in FCVs 
using the electrical isolation option because of this coolant-loop-
related issue.
---------------------------------------------------------------------------

    \10\ Records of these ex parte communications are available in 
the docket for the NPRM for this rule, Docket No. NHTSA-2008-28517.
---------------------------------------------------------------------------

    The Alliance/AIAM also commented on the agency's request for 
explanations of the practicality of measuring 0.2 Joules of energy in a 
crash test environment. NHTSA had stated in the NPRM that the SAE low-
energy option

[[Page 33520]]

of 0.2 Joules or less based on 10 ms of contact did not seem realistic 
in terms of an automobile crash. The Alliance/AIAM initially argued in 
response that SAE had not based the 0.2 Joules limit specifically on 10 
ms of contact, but rather had been looking for the minimum level of 
energy that might be harmful at any duration of contact, which was the 
border of zones 2 and 3 on the IEC charts. The border of zones 2 and 3 
(for a body current of 200 mA and a source of 200 VDC) ended up being 
0.4 Joules at 10 ms of contact, such that anything less than 0.4 Joules 
for any duration of contact would be in or below zone 2, and therefore 
safe from ventricular fibrillation. SAE then applied a safety factor of 
2 to get 0.2 Joules at 10 ms of contact.
    However, in their June 2009 supplemental comments, the Alliance 
presented a different approach to determining acceptable levels of 
electric energy. The Alliance argued that for current durations less 
than 2 seconds, no serious damage is observed with sufficiently low 
energy, even if the current passing through the body is relatively 
high. They explained that body current with durations less than 10 msec 
have little effect on involuntary muscular contraction. Therefore, the 
target threshold in this analysis used by the Alliance was intended to 
prevent ventricular fibrillation, and not just minimize muscular 
contraction. The commenter stated that according to paragraph 4.6 of 
the IEC 60429-1, the lowest level of human body impedance is 500 ohms.
    Applying this value of human body impedance along with the human 
body tolerance zones in Figure 22 of IEC 60429-1 and Figure 20 of IEC 
60429-2, the Alliance then computed the body current for a given time 
duration for which the energy is 0.2 Joules and 0.5 Joules. The 
commenter stated that in all instances, this line of 0.2 Joules energy 
plotted on Figure 22 of the IEC 60429-1 would be within zone 2, except 
at the 10 msec current duration, where the line is at the border of DC-
2 and DC-3 corresponding to 200 mA of body current. In addition, the 
line of 0.5 Joules energy intersects the border of DC-3 and DC-4.1 
(representing a 5 percent risk of ventricular fibrillation) for 
approximately 500 mA body current at 4.3 msec duration (Figure 20 of 
IEC 60429-2). The Alliance argued that based on this analysis, the 0.2 
Joules energy limit has a safety factor of 2.5 to prevent 5 percent 
risk of ventricular fibrillation.
    And finally, the Alliance/AIAM comments also argued that the 
agency's concern about measuring 0.2 Joules of energy in a crash test 
environment was misplaced, because energy can be ``easily and 
accurately calculated from the equation that energy (in Joules) = 0.5 * 
c * v\2\, where c is the capacitance of the capacitor(s) in farads and 
v is the measured voltage.'' The Alliance/AIAM stated that 
``Manufacturers routinely measure the voltage and calculate the 
associated energy without difficulty.''
    Agency response:
    Despite the Alliance/AIAM and Alliance's supplemental comments on 
this issue, NHTSA remains unpersuaded that a low-energy option of 0.2 
Joules for providing electrical safety is necessary for FMVSS No. 305 
at this time. Commenters have not provided any data that current FCVs 
or hybrid electric vehicles are unable to certify to the electrical 
safety requirements because of residual high voltage in the y-
capacitors. Their arguments are based entirely on theoretical values.
    In addition, we remain unconvinced that a low energy option is 
necessary and have concerns about the disparity between the level of 
safety provided by 0.2 Joules of energy and the electrical isolation 
requirement. The agency conducted its own analysis using the approach 
presented in the December 2007 Alliance/AIAM comments submission with 
several permutations of body current, body resistance, current 
duration, and safety factors to try to determine safe energy limits. 
Based on that analysis, the agency determined that applying different 
permutations of voltage levels, body resistance, shock duration, and 
factor of safety can result in different safe energy levels, some of 
which are less than the 0.2 J energy level specified in SAE J1766.
    Given that the IEC report indicates that the lowest human body 
impedance is a resistance of 500 ohms, and that the boundary between 
zones DC-2 and DC-3 is 200 mA of body current for 10 msec shock 
duration, we determined the corresponding amount of voltage through the 
Ohm's Law equation Current (A) * Resistance (ohms) = Voltage (V), in 
this case, 0.2 A * 500 ohms = 100 V. We then applied the same method 
used in SAE J1766 to calculate energy for a 10 msec shock duration with 
the equation Voltage (V) * Current (A) * Time (s) = Energy (J), in this 
case, 100 V * 0.2 A * 0.01 s = 0.2 J (or, equivalently, 200 mJ). The 
SAE applied a safety factor of 2. Doing the same for 200 mJ, the agency 
concluded that a safe energy level would correspond to 100 mJ--half the 
energy level specified in J1766 and recommended by Alliance/AIAM. 
Following the same procedure, for a voltage source of 65V and body 
resistance of 500 ohms, the body current was 130 mA, and the 
corresponding energy was 84.5 mJ.\11\ Applying a factor of safety of 2, 
the safe energy level was 42.2 mJ. Even without applying a factor of 
safety, the energy level is less than half of that recommended by the 
Alliance/AIAM. Based on this analysis, the agency concluded that the 
assumptions associated with voltage, current, and shock duration used 
to derive the proposed limit of 0.2 J for the energy option are not 
well supported.
---------------------------------------------------------------------------

    \11\ 0.13 A = 65/500; 0.0845 J = 65 * 0.13 * 0.01.
---------------------------------------------------------------------------

    Based on their assumptions, the Alliance's approach to determine 
minimum allowable energy levels presented in the June 2009 supplemental 
comments would allow body currents of 20 mA for shock duration of 1 
second, 28 mA for shock duration of 0.5 seconds, and 200 mA for shock 
duration of 10 msec. In contrast, the electrical isolation option of 
FMVSS No. 305 does not allow more than 10 mA of body current at either 
1 second, 0.5 seconds, or 10 msec shock duration.
    Additionally, the Alliance/AIAM comments recognized that according 
to the IEC Technical Committee 64, a point in the mid-range of AC zone 
2 is approximately equivalent to point in the mid-range of DC zone 2. 
The 28 mA of body current for a duration of 0.5 seconds that would be 
allowed by the low-energy option expressed by commenters is not in the 
mid-range of zone 2. It is, in fact, significantly closer to the border 
of zone 2 and zone 3, which indicates a higher level of risk for shock 
than the electrical isolation option of FMVSS No. 305. The agency thus 
believes that using a safety factor of 2.5 to protect against 
ventricular fibrillations in the low-energy option, as the Alliance 
supplemental comments suggest, would result in a higher risk level than 
that provided by the electrical isolation option of FMVSS No. 305, 
which protects against involuntary muscular contractions without any 
harmful physiological effects. Moreover, the Alliance has provided no 
technical basis for the assumption that for current durations less than 
2 seconds, no serious damage is observed with sufficiently low energy 
even if the current passing through the body is relatively high. The 
IEC charts clearly indicate that shock duration for one second is 
sufficiently long to cause involuntary muscular contractions, which are 
currently mitigated through the electrical isolation requirement of 
FMVSS No. 305.
    As for commenters' suggestion that the agency need not require 
measurement for the low energy option

[[Page 33521]]

and could simply make a calculation to verify compliance, the agency 
does not regard the Alliance/AIAM solution of calculating energy to be 
practicable for our purposes. The effective capacitance of a high 
voltage DC source will depend on the capacitance of individual 
capacitors in the source, the configuration of these capacitors, and 
the open/closed status of the contactors. This information is specific 
for each vehicle crash test, which means that the manufacturer-supplied 
capacitance value may be different from the effective capacitance after 
the crash test. Therefore, the computed energy of a high voltage source 
using the method recommended by Alliance/AIAM may not represent the 
true energy of the source after a crash test. Given the practical 
difficulties that we continue to see with including a low-energy option 
for providing electrical safety, and given the results of our analysis 
which shows that the energy option requested by commenters would be 
less stringent and pose a greater risk of electric shock hazard than 
the electrical isolation option, the agency is not including the low-
energy option for providing electrical safety in the final rule.

B. Other Issues Relating to the Electrical Isolation Requirement

    In the current FMVSS No. 305, sections S7.6.6 and S7.6.7 provide a 
method of computing electrical isolation in ohms/volt. However, in the 
NPRM, the agency inadvertently omitted specifying the method of 
determining electrical isolation in ohms/volts from the calculated 
isolation resistance. The Alliance/AIAM comments requested that the 
agency re-include similar language for S7.6.6 and S7.6.7 in the final 
rule, so that FMVSS No. 305 remains ``clear that nominal operating 
voltage is the applicable voltage for calculating the electrical 
isolation requirement.'' Along the same lines, the Alliance/AIAM 
requested that the agency add the word ``nominal'' in front of the word 
``volts'' in S3, to ensure that the standard is addressing ``nominal 
voltage.''
    The Alliance/AIAM comments also requested an alternative method of 
electrical isolation testing to the existing ``additional resistance 
insertion'' method, namely, use of a megohmmeter.\12\ The Alliance/AIAM 
argued that use of a megohmmeter was a valid alternative, and that 
Japanese and International Standards Organization (ISO) regulations 
both allow it. Honda, in comments submitted after the close of the 
comment period, concurred and offered similar information in more 
detail.\13\
---------------------------------------------------------------------------

    \12\ A megohmmeter, roughly speaking, is an instrument used for 
measuring electrical resistance which consists of two main elements: 
(1) A DC generator, which supplies the necessary voltage for taking 
the measurement, and (2) the instrument portion itself, which 
indicates the value of the resistance being measured.
    \13\ NHTSA-2007-28517-0006.
---------------------------------------------------------------------------

    Agency response:
    We agree with the Alliance/AIAM comment that specifying how 
electrical isolation in ohms/volt is computed is necessary to provide 
clarity and avoid confusion. The term ``nominal operating voltage'' is 
not defined in SAE J1766 itself, although SAE J1715 (2000)--Electrical 
Vehicle Technology, which is referenced by SAE J1766, defines ``nominal 
operating voltage'' as ``[t]he voltage of a battery, as specified by 
the manufacturer, discharging at a specified rate and temperature.'' 
However, this definition of nominal operating voltage only applies 
during normal operation. For purposes of FMVSS No. 305, in contrast, 
the electrical isolation and low voltage specifications are tested 
after a crash test when the vehicle need not be in normal operation and 
some of the contactors may have opened creating an open circuit 
condition. The agency thus believes that the term ``nominal operating 
voltage'' is not appropriate for this specification. Instead, the 
agency is using the term ``working voltage'' which is currently used in 
the proposal for the 01 series of amendments to ECE R.100.\14\ For 
purposes of FMVSS No. 305, working voltage for a voltage source in a 
circuit means ``the highest root mean square voltage of the voltage 
source, specified by the manufacturer, which may occur across its 
terminals or between its terminals and any conductive parts in open 
circuit conditions or under normal operating conditions.'' As defined, 
``working voltage'' applies during normal operation of the vehicle as 
well as in open circuit conditions and encompasses the possible range 
of conditions of a voltage source after a vehicle crash. Therefore, the 
agency believes that ``working voltage'' is more relevant for use in 
FMVSS No. 305, and will help to avoid the potential for confusion 
identified by the commenters.
---------------------------------------------------------------------------

    \14\ ECE/TRANS/WP.29/GRSP/2009/16, 23 September 2009. Available 
at http://www.unece.org/trans/doc/2009/wp29grsp/ECE-TRANS-WP29-GRSP-
2009-16e.pdf (last accessed Oct. 31, 2009).
---------------------------------------------------------------------------

    For consistency throughout the standard, the agency will use 
``working voltage'' to identify a vehicle as subject to FMVSS No. 305, 
to identify a source as ``high voltage,'' and to calculate electrical 
isolation in ohms/volt. Thus, the agency has added the following 
sentence in S7.6.6 and S7.6.7: ``Divide Ri (in ohms) by the working 
voltage of the high voltage source (in volts) to obtain the electrical 
isolation (in ohms/volt).'' The agency has also modified S3 to specify 
that working voltage shall be used for determining whether FMVSS No. 
305's requirements are applicable to a given vehicle, and has modified 
the definition for ``high voltage source'' in S4 based on the same 
reasoning.
    As for the use of megohmmeters for electrical isolation testing, 
NHTSA is still researching the use of megohmmeters for testing 
electrical isolation for purposes of FMVSS No. 305. Since the agency 
has reached no conclusions yet in that research, and since the use of 
megohmmeters was not raised in the NPRM and is thus outside the scope 
of this rulemaking, we are not providing additional test procedures for 
electrical safety using megohmmeters in this final rule. As the agency 
has noted in other rulemakings, manufacturers are not prohibited from 
using test procedures and devices other than those in the FMVSSs as a 
basis for their compliance certifications.

C. Comments Regarding Test Procedures

    In the NPRM, the agency tentatively accepted the premise that low 
voltage could be another way besides electrical isolation to provide 
electrical safety, but did not specifically include it in the proposed 
``electrical safety'' requirement and did not develop a test procedure 
for it. The Alliance/AIAM comments requested additional test procedure 
paragraphs (suggesting a new S7.7 and S7.8) for evaluating low voltage 
and low energy alternatives for providing electrical safety. The 
commenters suggested that the agency adopt the exact language used in 
SAE J1766.
    The NPRM also stated that the agency was not addressing the issue 
of crash testing FCVs in this rulemaking because of practical 
difficulties: Test procedures for safely crashing FCVs fueled with 
hydrogen have not been established; but without hydrogen, fuel cells 
will not generate any electrical energy from which to measure 
electrical output. The Alliance/AIAM comments suggested that the agency 
could take the same approach that the Japanese government does in its 
regulations, which call for the fuel cell to be filled with helium and 
then for using a megohmmeter to measure isolation. Honda, in its late 
comments, concurred with the Alliance/AIAM position.
    Agency response:
    We agree with the Alliance/AIAM that a test procedure paragraph 
should be added for the low voltage option for providing electrical 
safety, and have

[[Page 33522]]

revised the regulatory text accordingly. Since we remain unconvinced of 
the need for a low-energy option, as discussed above, we are not adding 
a test procedure for that option.
    Regarding the use of helium-filled fuel cells and megohmmeters for 
crash testing FCVs, we reiterate our position in the NPRM that the 
agency is still researching potential crash test methods for FCVs, and 
will not address this issue as part of this rulemaking.

D. Regulatory Text Wording

    The Alliance/AIAM comments contained a number of requests for 
greater specificity in and corrections to the regulatory text for the 
updated FMVSS No. 305.
    First, the Alliance/AIAM requested that the agency add the word 
``electric'' in multiple places in the regulatory text, so that it 
would be clear for hybrid vehicles that the agency intended to focus 
the FMVSS No. 305 requirements only on ``electric'' energy storage 
devices and not mechanical storage devices, like hydraulic 
accumulators. To that end, the commenters requested that a definition 
be added for ``electric energy storage device,'' and that S5.2, S7.1 
and S7.6.1 all have the word ``electric'' added.
    Agency response:
    We agree that the regulatory text should clarify that the agency 
means to apply the requirements of FMVSS No. 305 to electric energy 
storage devices only, and that a definition should be added for 
electric energy storage devices. We have revised the regulatory text 
accordingly.
    Second, the NPRM included a definition for ``energy storage 
system,'' but the Alliance/AIAM argued that FCVs are ``energy 
conversion systems'' and not ``energy storage systems,'' so the 
definition should be revised to accommodate both FCVs and battery-
powered electric vehicles.
    Agency response:
    We agree with the Alliance/AIAM comment, and have revised the 
regulatory text accordingly.
    Third, the NPRM defined a ``high voltage source'' as ``any item 
that produces voltage levels equal to or greater than 30 VAC or 60 
VDC.'' The Alliance/AIAM stated that since S3, the application 
paragraph, states that FMVSS No. 305 applies to vehicles that use 
``more than'' 60 VDC or 30 VAC, the words ``equal to or'' should be 
removed from the definition of high voltage source.
    Agency response:
    We agree with the Alliance/AIAM comment, and have revised the 
regulatory text accordingly.
    Fourth, the Alliance/AIAM requested that the agency add a 
definition for ``propulsion system,'' a term used in S7.6.1 of FMVSS 
No. 305, but not defined. The Alliance/AIAM suggested that the 
definition read as follows:

    Propulsion system means the components or electric circuit to 
propel the vehicle using the energy that is supplied by a high 
voltage source. These include, but are not limited to, the 
propulsion motor, electric converter, associated wire harnesses and 
connectors.

    Agency response:
    We agree that this would be a useful definition, and have added it 
to the regulatory text.
    And fifth, the Alliance/AIAM suggested the following editorial 
corrections: Figure 1 should refer to S7.6.3, not S7.6.6; in Figure 4, 
V1 should be V1', and the denominator should be V1'; and in Figure 5, 
the denominator should be V2'.
    Agency response:
    We agree with these corrections and have revised the regulatory 
text accordingly.

E. Physical Barriers as an Additional Option for Providing Electrical 
Safety

    The Alliance/AIAM also requested another compliance option that was 
not included in SAE J1766, but is included in the Japanese regulation 
for electrical vehicle safety. The commenters stated that ``This new 
option would allow for isolation from high voltage sources via physical 
barriers that are in place to insure that there is no direct or 
indirect contact with live voltage sources after a vehicle crash.'' 
This would be safe, the commenters argued, because ``if a person cannot 
access the potentially high voltage sources, then there is little 
chance of the occupants or rescue personnel helping the occupants from 
being injured from such sources.'' The Alliance/AIAM stated that this 
alternative compliance option was necessary because some FCVs may ``use 
capacitors that take some time to discharge,'' and allowing it would 
provide ``greater flexibility in order to allow introduction of 
advanced powertrain technologies.'' However, the Alliance/AIAM 
recognized that the agency might not be able to include this option in 
the final rule for procedural reasons, and requested that if this were 
so, the agency ``publish a separate NPRM to address the option of using 
a physical barrier to provide electrical safety.''
    The Alliance further elaborated on this compliance option in their 
June 2009 supplemental comments. They stated that the DC components of 
the fuel cell can connect with the AC components through the inverter, 
even when the vehicle is stationary, after certain crash tests that may 
not result in the opening of the contactors. In such a condition, when 
the contactors are closed and the DC and AC components are connected, 
the isolation resistance at the AC component is in parallel with the 
isolation resistance of the DC component fuel cell. Therefore, even if 
the electrical isolation provided for the AC component is significantly 
greater than the required 500 ohms/volt, the effective isolation 
resistance measured at the AC component can be, at most, as high as 
that provided for the DC component fuel cell, which is in turn limited 
by the fuel cell coolant. Therefore, it may not be practical to achieve 
the required 500 ohms/volt electrical isolation for the AC component. 
The Alliance thus argued that there is a need to include finger-proof 
barriers \15\ in FMVSS No. 305 as a fourth alternative.
---------------------------------------------------------------------------

    \15\ Barriers that prevent a finger-sized probe from penetrating 
into an enclosed space.
---------------------------------------------------------------------------

    The Alliance also stated in their supplemental comments that the 
finger-proof barrier is similar to an option that already exists in 
FMVSS No. 305 for battery packs, where the electrical isolation 
measurement is made from the traction side of the automatic disconnect 
that is enclosed and is physically contained within the battery pack 
system. They argued that the protective barrier option would be further 
strengthened by requiring that the barrier remain finger-proof after 
the crash. The commenter also stated that for electric vehicles that 
provide galvanic bonding for conductive materials that are not designed 
to conduct electrical current for vehicle operation,\16\ such as the 
vehicle chassis electrical conducting structure (a design requirement 
by SAE J2578--Recommended Practice for General Fuel Cell Vehicle 
Safety), the only current potentially remaining in the FCV after a 
crash is in the high voltage components themselves. As long as those 
components are guarded by finger-proof barriers, the commenter argued 
that there would be no risk of electric shock to the first responder or 
the vehicle occupant after a crash.
---------------------------------------------------------------------------

    \16\ ``Galvanic bonding'' refers to a direct electrical 
connection, in this case for conductive materials not designed 
specifically to conduct electrical current for vehicle operation, as 
opposed to a capacitive or inductive connection.
---------------------------------------------------------------------------

    Agency response:
    The use of physical barriers as another option for providing 
electrical safety is beyond the scope of this rulemaking, as the 
Alliance/AIAM comments acknowledged. The agency is not familiar with 
the proposed

[[Page 33523]]

methodology and would have to examine the issue further to judge its 
suitability for inclusion in FMVSS No. 305. While the Alliance 
supplemental comments stress the efficacy of the protective barrier 
option for electric shock protection due to direct contact with high 
voltage sources, there are many possible failure modes in which vehicle 
occupants and rescue workers are at risk of electric shock due to 
indirect contact. Additionally, the design guidelines in SAE J2578 on 
which the Alliance comments rely to provide protection against electric 
shock due to indirect contact require that all conductive materials in 
the vehicle be galvanically bonded if they are not designed to conduct 
electrical current for vehicle operation. However, the commenters 
suggested no test procedure to confirm that a vehicle has been designed 
to meet this design requirement specified in SAE J2578. The agency is 
thus uncertain whether indirect contact failure modes would be 
sufficiently accounted for by this design requirement.
    For these reasons, we are not including a finger-proof protective 
barrier option in FMVSS No. 305 as requested by the Alliance and other 
manufacturers in their comments to the NPRM. However, the agency has 
initiated a research program to get a better understanding of the 
issues related to requiring this as an option to satisfy electrical 
safety.

F. Effective Date

    In the NPRM, NHTSA proposed that the amendments made by this 
rulemaking would apply to vehicles manufactured on or after one year 
from the date of publication of the final rule, with optional early 
compliance. The agency believed that one year should be sufficient for 
manufacturers to verify that they can meet the new electrical isolation 
requirements, particularly since similar requirements already exist as 
a SAE recommended practice and currently, all manufacturers of 
electric-powered vehicles already isolate the high voltage sources from 
the vehicle chassis.
    NHTSA did not receive any comments related to the proposed 
effective date during the comment period. However, in comments provided 
by Toyota (June 24, 2009), the manufacturer requested that the 
effective date be set three years from the date the final rule is 
published. Thus, it said, if the final rule were issued by September 1, 
2009, compliance should not be required before September 2012. They 
argued that the additional time was needed so that they could 
incorporate the necessary changes across their current and near future 
HEVs to comply with the new electric safety requirements.
    Agency response:
    The agency evaluated the information provided by Toyota and is not 
convinced that leadtime of three full model years from the publication 
of the final rule is needed in order for their current and near future 
HEVs to comply with the amended requirements in FMVSS No. 305. We 
continue to believe that Toyota's HEVs in the current fleet already 
comply with the amended requirements, given that similar performance 
criteria were added to SAE J1766 in April 2005 at the request of the 
Alliance. Plans for their near future HEVs presumably include means of 
complying with those criteria.
    Moreover, in their comments, Toyota stated expressly that their 
current HEVs include battery disconnection and inverter shut-down in 
the event of a crash. NHTSA believes that these features should allow 
these vehicles to comply with the electrical safety requirements using 
a combination of the low voltage option and the electrical isolation 
option for all high voltage components. NHTSA does not anticipate that 
near future HEV (or other electric vehicle) designs will be so 
different from current ones that they will be unable to comply with 
either the low voltage option or the electrical isolation option, or 
some combination thereof. Therefore, we have decided that one year lead 
time is sufficient to comply with the amended requirements in FMVSS No. 
305. Accordingly, this final rule will become effective on September 1 
in the year after the final rule is issued.

G. Hyundai Request for Interpretation on S5.2 Battery Retention

    On March 9, 2009, Hyundai requested an interpretation of language 
in S5.2, ``Battery retention.'' Hyundai argued that as currently 
written, the language of S5.2 allows a battery module located outside 
the passenger compartment to become dislodged as long as it does not 
enter the occupant compartment, while a module that is located within 
the occupant compartment must simply remain in the location in which 
they are installed. Hyundai stated that this may not properly address 
the intent of the standard in some circumstances. Hyundai referred to 
the preamble of the final rule, which stated that the intended purpose 
of not allowing battery modules located outside the occupant 
compartment was ``to ensure that battery modules would not become 
unattached and become flying projectiles in a crash or subsequent 
rollover.'' \17\ Hyundai also argued that FMVSS No. 305 does not 
provide a definition of the passenger compartment, but that a previous 
interpretation to Mazda implied that the passenger compartment was an 
area that shares ``occupant air space'' that included the area where 
people ride. Hyundai stated that a portion of a properly restrained 
battery module located outside the occupant compartment, may move into 
the occupant compartment during a test due to deformation of the 
vehicle structure without rupturing the mounting points and without 
becoming a ``flying projectile.'' They further argued that in a vehicle 
such as a sport utility vehicle (SUV) or station wagon, where a battery 
module is located inside the occupant compartment and moves during 
impact due to the deformation of the floor, but remains firmly attached 
to its mounting, would technically fail the test.
---------------------------------------------------------------------------

    \17\ 65 FR 57985 (Sept. 27, 2000).
---------------------------------------------------------------------------

    Hyundai suggested that the proper interpretation of the language 
should not treat these two conditions separately. They argued that in 
the case where a battery module remains attached to the location in 
which it is installed but due to deformation of the vehicle structure, 
it moves or causes a portion of the module to enter the occupant 
compartment, NHTSA should not consider these to constitute a failure of 
the standard.
    Agency response:
    We have decided to respond to Hyundai's request for interpretation 
of S5.2 in this final rule because the NPRM had already proposed to 
modify the language in S5.2. The agency agrees that battery modules 
located inside the occupant compartment technically may move a small 
amount from the location from which they are installed during the 
impact tests. The agency also agrees that battery modules located 
outside the occupant compartment that partially move into the occupant 
compartment because of structural deformation of the vehicle structure 
do not impose a projectile hazard provided that they remain attached to 
the mounting structure. Therefore, the agency concurs that battery 
modules located outside the occupant compartment should be treated in 
the same manner as those located inside the occupant compartment, 
provided that they remain attached to their anchorages. Technical 
changes to the proposed text in S5.2 have been made accordingly.

[[Page 33524]]

H. Preemption

    In the view of AAJ, NHTSA's discussion in the FMVSS No. 305 NPRM of 
the 2000 Supreme Court case, Geier v. American Honda Motor Co., 529 
U.S. 861, and the agency's assessment of the possibility of preemption 
represented a ``sudden decision to claim [implied] preemption'' of 
State tort law.
    Agency response:
    As an initial matter, we wish to emphasize our strong belief that 
State law can play an important role in safeguarding public safety. In 
the words of the President's May 20, 2009 memorandum on preemption:

    * * * State law and national law often operate concurrently to 
provide independent safeguards for the public. Throughout our 
history, State and local governments have frequently protected 
health, safety, and the environment more aggressively than has the 
national Government.

Consistent with that memorandum, we have examined past rulemaking 
notices to determine if they contained statements finding implied 
preemption of State law. The highlights of that examination are set 
forth below.

    We believe that a fundamental misunderstanding lies at the heart of 
AAJ's characterization of that discussion and assessment in the 
Standard No. 305 NPRM and of similar discussions and assessments in 
approximately two dozen other vehicle safety standard rulemaking 
notices issued from February 2007 to November 2008. This agency did not 
express or even suggest any intent to preempt State tort law impliedly 
in those rulemaking notices. Instead, this agency responded to the 
requirements of Executive Order 13132 (Federalism) in part by examining 
whether there might be any possible basis for a judicial finding of 
implied preemption of state tort law. In each of those notices, the 
agency concluded its examination without identifying any potential 
obstacle or conflict that might give rise to such a finding and without 
even suggesting that there was any probability that one might exist in 
the future. As the agency has increasingly emphasized in other vehicle 
safety standard rulemaking notices, it is fundamental that without any 
obstacle or conflict, there cannot be any implied preemption.
    Those approximately two dozen 2007-2008 notices contrast markedly 
with three vehicle safety standard rulemaking notices issued in mid-
2005. In those three notices, this agency did state that it discerned a 
potential obstacle or conflict that might be posed by state tort law 
and stated further that if a court found that an obstacle or conflict 
existed, it could result in the court's finding that such state tort 
law was impliedly preempted. Further, in each of those three 
rulemakings, the agency was unmistakably explicit in identifying the 
potential existence and nature of the obstacle or conflict.
    Those three notices were the June 2005 NPRM on designated seating 
positions; \18\ the August 2005 NPRM on roof crush; \19\ and the 
September 2005 NPRM on rearview mirrors.\20\ In each of those NPRMs, 
the agency identified types of state requirements that it had discerned 
and said might create a conflict and therefore might be found to be 
impliedly preempted as a result of the rulemaking.
---------------------------------------------------------------------------

    \18\ 70 FR 36094, 36098 (June 22, 2005).
    \19\ 70 FR 49223, 49245-6 (August 23, 2005).
    \20\ 70 FR 53753, 53768-9 (September 12, 2005).
---------------------------------------------------------------------------

    We note that none of the statements about preemption in those three 
rulemakings is still operative. The final disposition of each of those 
statements is as follows--
     Rearview mirrors--The tentative statement about preemption 
in the proposal was never finally adopted. It became moot when the 
agency withdrew this rulemaking in July 2008 without ever issuing a 
final rule.\21\
---------------------------------------------------------------------------

    \21\ 73 FR 42309 (July 21, 2008).
---------------------------------------------------------------------------

     Roof crush--In the final rule on roof crush published on 
May 12, 2009, the agency said that it no longer perceived any potential 
conflicts or obstacles, and accordingly stated there was no likelihood 
of a court's finding there to be any implied preemption of State tort 
law; \22\ and
---------------------------------------------------------------------------

    \22\ 74 FR 22348, 22380-83 (May 12, 2009).
---------------------------------------------------------------------------

     Designated seating position--In response to petitions for 
reconsideration of the agency's inclusion in procedures for determining 
the number of ``designated seating positions'' in a motor vehicle of a 
statement declaring the preemptive effect of those procedures, the 
agency recently issued a final rule deleting that statement from the 
regulatory text and said, as it did in the roof crush final rule, that 
it no longer perceived any obstacles or conflict, and accordingly there 
was no likelihood of a court's finding there to be any implied 
preemption of State tort law.\23\
---------------------------------------------------------------------------

    \23\ 74 FR 68185 (December 23, 2009).
---------------------------------------------------------------------------

    The 2007-2008 notices, including the FMVSS No. 305 NPRM, are 
completely different from those three 2005 rulemakings. Although AAJ 
characterized the preemption assessment in the FMVSS No. 305 NPRM, as 
it has similar preemption assessments in the other 2007-2008 vehicle 
safety notices, as an assertion of implied preemption of State tort 
law, a careful reading of the agency's discussions under Executive 
Order 13132 does not support that characterization. The pertinent 
paragraph in the FMVSS No. 305 NPRM reads as follows:

    In addition to the express preemption noted above, the Supreme 
Court has also recognized that State requirements imposed on motor 
vehicle manufacturers, including sanctions imposed by State tort 
law, can stand as an obstacle to the accomplishment and execution of 
a NHTSA safety standard. When such a conflict is discerned, the 
Supremacy Clause of the Constitution makes their State requirements 
unenforceable. See Geier v. American Honda Motor Co., 529 U.S. 861 
(2000). NHTSA has not outlined such potential State requirements in 
today's rulemaking, however, in part because such conflicts can 
arise in varied contexts, but it is conceivable that such a conflict 
may become clear through subsequent experience with today's standard 
and test regime. NHTSA may opine on such conflicts in the future, if 
warranted. See id. at 883-86.\24\
---------------------------------------------------------------------------

    \24\ 72 FR 57260, 57265 (October 9, 2007).

    This discussion does not contain any statement that that particular 
rulemaking was intended to or had the effect of impliedly preempting 
State law. Further, neither the discussion in the FMVSS No. 305 NPRM 
nor any of the other similar discussions in the other vehicle safety 
rulemaking notices was viewed by the agency at the time of issuance as 
an assertion of implied preemption with respect to the safety standard 
under discussion, and none of them is so viewed now. The agency did not 
at the time of issuing any of those notices suggest the existence of 
any obstacle or other conflict that might give rise to a judicial 
finding of implied preemption, and does not now discern, or anticipate 
the possibility of, any obstacle or conflict.
    Far from indicating in the FMVSS No. 305 NPRM that it had found an 
obstacle or conflict, the agency stated that it had ``not outlined'' 
any obstacles or conflicts. The agency went further, indicating to the 
contrary that there were no clear obstacles or conflicts. These 
judgments were based in part upon the agency's consideration of the 
nature (e.g., the language and structure of the regulatory text) and 
objectives of each of the rules. Since without obstacle or conflict, 
there could not be any implied preemption of State tort law, the agency 
did not anticipate that those discussions would somehow be 
characterized as assertions of implied preemption of State tort law.
    Nevertheless, since misunderstandings occurred and continued to 
occur, the agency initiated

[[Page 33525]]

in late summer of 2008 a progressive and continuing series of 
evolutionary efforts to clarify the language of similar agency 
discussions in subsequent vehicle safety notices.
    It did so first by removing and replacing the statement that the 
agency ``has not outlined'' any obstacles or conflicts. Recognizing 
that some persons might be concerned that such a statement leaves open 
the theoretical possibility that obstacles or conflicts might have been 
discerned, but not outlined, the agency sought to ensure that that 
possibility was clearly negated. Beginning with a September 2008 
proposal on seat belt lockability, the agency switched to affirmatively 
stating that the agency ``has not discerned'' any obstacles or 
conflicts:

    NHTSA has not discerned any conflict in today's rulemaking. 
However, in part because such conflicts can arise in varied 
contexts, the agency cannot rule out the possibility that such a 
conflict may become clear through subsequent experience with the 
proposed standard and test regime. NHTSA may opine on such conflicts 
in the future, if warranted.\25\
---------------------------------------------------------------------------

    \25\ 73 FR 52939, 52941 (September 12, 2008).

    As this clarification did not bring an end to the petitions from 
AAJ, the agency made further clarifying changes in an early March 2009 
---------------------------------------------------------------------------
interim final rule on air brake systems:

    NHTSA has considered today's interim final rule and does not 
currently foresee any potential State requirements that might 
conflict with it.\26\
---------------------------------------------------------------------------

    \26\ 74 FR 9173, 9175 (March 3, 2009).

    For further emphasis, the agency added an additional sentence to 
its discussion under E.O. 13132 to emphasize the fundamental 
significance of not discerning any conflicts or obstacles:
    Without any conflict, there could not be any implied 
preemption.\27\
---------------------------------------------------------------------------

    \27\ Id. The full discussion reads as follows:* * * the Supreme 
Court has recognized the possibility of implied preemption: State 
requirements imposed on motor vehicle manufacturers, including 
sanctions imposed by State tort law, can stand as an obstacle to the 
accomplishment and execution of a NHTSA safety standard. When such a 
conflict is discerned, the Supremacy Clause of the Constitution 
makes the State requirements unenforceable. See Geier v. American 
Honda Motor Co., 529 U.S. 861 (2000). NHTSA has considered today's 
interim final rule and does not currently foresee any potential 
State requirements that might conflict with it. Without any 
conflict, there could not be any implied preemption.
---------------------------------------------------------------------------

    In August 2009, the agency began including a brief description of 
what the agency typically considers in assessing whether there might be 
any conflict or obstacle. The essential point in the notice remained 
that the agency had not identified any conflict or obstacle:

    Second, the Supreme Court has recognized the possibility of 
implied preemption: In some instances, State requirements imposed on 
motor vehicle manufacturers, including sanctions imposed by State 
tort law, can stand as an obstacle to the accomplishment and 
execution of a NHTSA safety standard. When such a conflict is 
discerned, the Supremacy Clause of the Constitution makes the State 
requirements unenforceable. See Geier v. American Honda Motor Co., 
529 U.S. 861 (2000). However, NHTSA has considered the nature and 
purpose of today's rule and does not currently foresee any potential 
State requirements that might conflict with it. Without any 
conflict, there could not be any implied preemption. (Emphasis 
added.) \28\
---------------------------------------------------------------------------

    \28\ 74 FR 40760, 40763-4 (August 13, 2009).

    This discussion, and the one below in Section III.C assessing this 
final rule under Executive Order 13132, represent the latest in the 
continuing series of clarifications to assuage concerns, ensure an end 
to the misunderstandings, and promote consistency with the President's 
May 20, 2009 memorandum on preemption.\29\ The pertinent portion of the 
Section III.C discussion reads as follows:
---------------------------------------------------------------------------

    \29\ The President's memorandum recognizes that State law and 
national law often operate concurrently to provide independent 
safeguards for the public and states that the general policy of his 
Administration is that preemption of State law by executive 
departments and agencies should be undertaken only with full 
consideration of the legitimate prerogatives of the States and with 
a sufficient legal basis for preemption. See http://
www.whitehouse.gov/the_press_office/presidential-memorandum-
regarding-preemption/ (last accessed February 4, 2010).

    Second, the Supreme Court has recognized the possibility, in 
some instances, of implied preemption of State requirements imposed 
on motor vehicle manufacturers, including sanctions imposed by State 
tort law. That possibility is dependent upon there being an actual 
conflict between a FMVSS and the State requirement. If and when such 
a conflict exists, the Supremacy Clause of the Constitution makes 
the State requirements unenforceable. See Geier v. American Honda 
Motor Co., 529 U.S. 861 (2000), finding implied preemption of State 
tort law on the basis of a conflict discerned by the court, not on 
the basis of an intent to preempt asserted by the agency itself.
    NHTSA has considered the nature (e.g., the language and 
structure of the regulatory text) and objectives of today's final 
rule and does not discern any existing State requirements that 
conflict with the rule or the potential for any future State 
requirements that might conflict with it. Without any conflict, 
there could not be any implied preemption of State law, including 
state tort law.

III. Rulemaking Analyses and Notices

A. Executive Order 12866 and DOT Regulatory Policies and Procedures

    This rulemaking document was not reviewed by the Office of 
Management and Budget under E.O. 12866. It is not considered to be 
significant under E.O. 12866 or the Department's Regulatory Policies 
and Procedures (44 FR 11034; Feb. 26, 1979). This final rule will have 
no significant effect on the national economy as it simply provides 
alternative means for achieving compliance and aligns FMVSS No. 305 
with current industry recommended practices to facilitate the 
development and introduction of fuel cell vehicles and next generation 
electric powered vehicles into the market.

B. Regulatory Flexibility Act

    NHTSA has considered the effects of this final rule under the 
Regulatory Flexibility Act (5 U.S.C. 601 et seq., as amended by the 
Small Business Regulatory Enforcement Fairness Act (SBREFA) of 1996). I 
certify that this final rule will not have a significant economic 
impact on a substantial number of small entities. Any small 
manufacturers that might be affected by this final rule are already 
subject to the requirements of FMVSS No. 305. Further, the agency 
believes the testing associated with the requirements added by this 
final rule are not substantial and to some extent are already being 
voluntarily borne by the manufacturers pursuant to SAE J1766. 
Therefore, there will be only a minor economic impact.

C. Executive Order 13132 (Federalism)

    NHTSA has examined today's final rule pursuant to Executive Order 
13132 (64 FR 43255; Aug. 10, 1999) and concluded that no additional 
consultation with States, local governments, or their representatives 
is mandated beyond the rulemaking process. The agency has concluded 
that the rule does not have sufficient federalism implications to 
warrant consultation with State and local officials or the preparation 
of a federalism summary impact statement. The rule does not have 
``substantial direct effects on the States, on the relationship between 
the national government and the States, or on the distribution of power 
and responsibilities among the various levels of government.''
    NHTSA rules can have preemptive effect in two ways. First, the 
National Traffic and Motor Vehicle Safety Act contains an express 
preemption provision:

    When a motor vehicle safety standard is in effect under this 
chapter, a State or a political subdivision of a State may prescribe 
or continue in effect a standard applicable to the same aspect of 
performance of a motor vehicle or motor vehicle equipment only if 
the standard is identical to the standard prescribed under this 
chapter.

[[Page 33526]]

49 U.S.C. 30103(b)(1). It is this statutory command that preempts any 
non-identical State legislative and administrative law \30\ addressing 
the same aspect of performance, not today's rulemaking, so consultation 
would be inappropriate.
---------------------------------------------------------------------------

    \30\ The issue of potential preemption of State tort law is 
addressed in the immediately following paragraph discussing implied 
preemption.
---------------------------------------------------------------------------

    Second, the Supreme Court has recognized the possibility, in some 
instances, of implied preemption of State requirements imposed on motor 
vehicle manufacturers, including sanctions imposed by State tort law. 
That possibility is dependent upon there being an actual conflict 
between a FMVSS and the State requirement. If and when such a conflict 
exists, the Supremacy Clause of the Constitution makes the State 
requirements unenforceable. See Geier, v. American Honda Motor Co., 529 
U.S. 861 (2000), finding implied preemption of State tort law on the 
basis of a conflict discerned by the court,\31\ not on the basis of an 
intent to preempt asserted by the agency itself.\32\
---------------------------------------------------------------------------

    \31\ The conflict was discerned based upon the nature (e.g., the 
language and structure of the regulatory text) and the safety-
related objectives of FMVSS requirements in question and the impact 
of the State requirements on those objectives.
    \32\ Indeed, in the rulemaking that established the rule at 
issue in this case, the agency did not assert preemption.
---------------------------------------------------------------------------

    NHTSA has considered the nature (e.g., the language and structure 
of the regulatory text) and objectives of today's final rule and does 
not discern any existing State requirements that conflict with the rule 
or the potential for any future State requirements that might conflict 
with it. Without any conflict, there could not be any implied 
preemption of state law, including State tort law.

D. National Environmental Policy Act

    NHTSA has analyzed this rulemaking action for the purposes of the 
National Environmental Policy Act. The agency has determined that 
implementation of this action will not have any significant impact on 
the quality of the human environment.

E. Executive Order 12988 (Civil Justice Reform)

    With respect to the review of the promulgation of a new regulation, 
section 3(b) of Executive Order 12988, ``Civil Justice Reform'' (61 FR 
4729; Feb. 7, 1996), requires that Executive agencies make every 
reasonable effort to ensure that the regulation: (1) Clearly specifies 
the preemptive effect; (2) clearly specifies the effect on existing 
Federal law or regulation; (3) provides a clear legal standard for 
affected conduct, while promoting simplification and burden reduction; 
(4) clearly specifies the retroactive effect, if any; (5) specifies 
whether administrative proceedings are to be required before parties 
file suit in court; (6) adequately defines key terms; and (7) addresses 
other important issues affecting clarity and general draftsmanship 
under any guidelines issued by the Attorney General. This document is 
consistent with that requirement.
    Pursuant to this Order, NHTSA notes as follows. The issue of 
preemption is discussed above. NHTSA notes further that there is no 
requirement that individuals submit a petition for reconsideration or 
pursue other administrative proceedings before they may file suit in 
court.

F. Privacy Act

    Please note that anyone is able to search the electronic form of 
all comments received into any of our dockets by the name of the 
individual submitting the comment (or signing the comment, if submitted 
on behalf of an association, business, labor union, etc.). You may 
review DOT's complete Privacy Act Statement in the Federal Register 
published on April 11, 2000 (65 FR 19477-78), or online at http://
www.dot.gov/privacy.html.

G. Paperwork Reduction Act

    Under the Paperwork Reduction Act of 1995 (PRA), a person is not 
required to respond to a collection of information by a Federal agency 
unless the collection displays a valid OMB control number. There are no 
information collection requirements associated with this final rule.

H. National Technology Transfer and Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (NTTAA), Public Law 104-113, as amended by Public Law 107-
107 (15 U.S.C. 272), directs the agency to evaluate and use voluntary 
consensus standards in its regulatory activities unless doing so would 
be inconsistent with applicable law or is otherwise impractical. 
Voluntary consensus standards are technical standards (e.g., materials 
specifications, test methods, sampling procedures, and business 
practices) that are developed or adopted by voluntary consensus 
standards bodies, such as the Society of Automotive Engineers (SAE). 
The NTTAA directs us to provide Congress (through OMB) with 
explanations when the agency decides not to use available and 
applicable voluntary consensus standards. The NTTAA does not apply to 
symbols.
    FMVSS No. 305 has historically drawn largely from SAE J1766, and 
does so again for this current rulemaking, which updates FMVSS No. 305 
based on the April 2005 version of SAE J1766. In accordance with SAE 
J1766, this final rule (a) specifies electrical safety requirements to 
all high voltage sources and not just the propulsion battery, (b) 
distinguishes between AC and DC high voltage sources and specifies 
electrical isolation of 500 ohms/volt for AC high voltage sources and 
100 ohms/volt for DC high voltage sources with continuous isolation 
monitoring during vehicle operation, and (c) permits a low voltage 
option to comply with electrical safety requirements. NHTSA is not, 
however, adopting SAE J1766 verbatim into the FMVSSs and has not 
adopted the electrical energy option for electrical safety that is 
permitted in SAE J1766 because our analysis indicates that it is less 
stringent and poses a greater risk of electric shock hazard than the 
electrical isolation option. In addition, the method proposed by 
commenters for determining compliance with the low energy option was 
found not to be practical for the agency's purpose.
    In the NPRM, NHTSA requested public comment on the appropriateness 
of also considering the 2006 International Organization for 
Standardization (ISO) standard ISO 23273-3, ``Fuel cell road vehicles--
safety specifications--Part 3: Protection of persons against electric 
shock.'' No comments were received on this issue. This ISO standard 
which specifies in-use requirements of fuel cell vehicles for the 
protection of persons and the environment inside and outside the 
vehicles against electric shock, is currently in the process of being 
superseded by another standard under development, ISO-6469-3, 
``Electric road vehicles--safety specifications--part 3: Protection of 
persons against electric hazards.'' Since the purpose of FMVSS No. 305 
is to reduce deaths and injuries during a crash and not during vehicle 
operation as in the ISO standard and since the ISO standard is still in 
flux, the agency is not incorporating any part of this standard into 
this final rule.

IV. Regulatory Text

List of subjects in 49 CFR Part 571

    Imports, Motor vehicles, Motor vehicle safety.

0
In consideration of the foregoing, NHTSA amends 49 CFR part 571.305 as 
follows:

[[Page 33527]]

PART 571--FEDERAL MOTOR VEHICLE SAFETY STANDARDS

0
1. The authority citation for part 571 continues to read as follows:

    Authority: 49 U.S.C. 322, 30111, 30115, 30117, and 30166; 
delegation of authority at 49 CFR 1.50.

0
2. Amend Sec.  571.305 by revising S1, S2, S3, S4, S5, S5.2, S5.3, 
S6.2, S7, S7.1, S7.2, S7.4, S7.6, S7.6.1, S7.6.2, S7.6.3, S7.6.4, 
S7.6.5, S7.6.6, S7.6.7, Figure 1, Figure 2, Figure 3, Figure 4, and 
Figure 5, and adding S5.4, S7.7, and S8 to read as follows:

Sec.  571.305  Standard No. 305; Electric-powered vehicles: Electrolyte 
spillage and electrical shock protection.

    S1. Scope. This standard specifies requirements for limitation of 
electrolyte spillage, retention of electric energy storage devices, and 
protection from harmful electric shock during and after a crash.
    S2. Purpose. The purpose of this standard is to reduce deaths and 
injuries during and after a crash that occur because of electrolyte 
spillage from electric energy storage devices, intrusion of electric 
energy storage device components into the occupant compartment, and 
electrical shock.
    S3. Application. This standard applies to passenger cars, and to 
multipurpose passenger vehicles, trucks, and buses that have a GVWR of 
4,536 kg or less, that use electrical components with working voltages 
more than 60 volts direct current (VDC) or 30 volts alternating current 
(VAC), and whose speed attainable over a distance of 1.6 km on a paved 
level surface is more than 40 km/h.
    S4. Definitions.
    Electrical isolation means the electrical resistance between the 
vehicle high voltage source and any vehicle conductive structure.
    Electric energy storage/conversion/power generating system means 
the components comprising, but not limited to, the vehicle's high 
voltage battery system, capacitor system, or fuel cell system, and 
rechargeable energy storage systems. These include, but are not limited 
to, the battery or capacitor modules, interconnects, venting systems, 
battery or capacitor restraint devices, and electric energy storage 
boxes or containers that hold the individual battery or capacitor 
modules. Hydrogen system components of fuel cell vehicles, such as the 
hydrogen tanks and hydrogen tubes, are not included in the electric 
energy storage/conversion system.
    Electric energy storage device means a high voltage source that can 
store energy, such as a battery or capacitor modules.
    High voltage source means any electric component that has a working 
voltage greater than 30 VAC or 60 VDC.
    Propulsion system means the components or electric circuit to 
propel the vehicle using the energy that is supplied by a high voltage 
source. These include, but are not limited to, the propulsion motor, 
electric converter, and associated wire harnesses and connectors, and 
coupling systems for charging rechargeable energy storage systems.
    Working voltage means the highest root mean square voltage of the 
voltage source, which may occur across its terminals or between its 
terminals and any conductive parts in open circuit conditions or under 
normal operating conditions.
    VAC means volts of alternating current (AC).
    VDC means volts of direct current (DC).
    S5. General Requirements. Each vehicle to which this standard 
applies, must meet the requirements in S5.1, S5.2, and S5.3 when tested 
according to S6 under the conditions of S7.
* * * * *
    S5.2 Electric energy storage/conversion system retention. All 
components of the electric energy storage/conversion system must be 
anchored to the vehicle. All component anchorages, including any 
brackets or structures that transfer loads from the component to the 
vehicle structure, shall remain attached to the vehicle structure at 
all attachment locations during and after testing performed pursuant to 
the procedures of S6 of this standard.
    S5.3 Electrical safety. After each test, each high voltage source 
in a vehicle must meet the electrical isolation requirements of 
subparagraph (a) or the voltage level requirements of subparagraph (b).
    (a) The electric isolation between each high voltage source and the 
vehicle chassis electricity-conducting structure must meet one of the 
following:
    (1) Electrical isolation must be greater than or equal to 500 ohms/
volt for all DC high voltage sources without continuous monitoring of 
electrical isolation during vehicle operation and for all AC high 
voltage sources; or
    (2) Electrical isolation must be greater than or equal to 100 ohms/
volt for all DC high voltage sources with continuous monitoring of 
electrical isolation, in accordance with the requirements of S5.4, 
during vehicle operation.
    (b) The voltage of the voltage source must be less than or equal to 
30 VAC for AC components or 60 VDC for DC components.
    S5.4 Electrical isolation monitoring. For each continuously 
monitored DC high voltage source, the continuous monitoring of 
electrical isolation during vehicle operation referred to in S5.3(a)(2) 
must be achieved through an electrical isolation monitoring system that 
displays a warning for loss of isolation when tested according to S8. 
The system must monitor its own readiness and the warning display must 
be clearly visible from the driver's designated seating position.
* * * * *
    S6.2 Rear moving barrier impact. The vehicle must meet the 
requirements of S5.1, S5.2, and S5.3 when it is impacted from the rear 
by a barrier that conforms to S7.3(b) of 571.301 of this chapter and 
that is moving at any speed up to and including 80 km/h (50 mph) with 
dummies in accordance with S6.2 of 571.301 of this chapter.
* * * * *
    S7. Test conditions. When the vehicle is tested according to S6, 
the requirements of S5.1 through S5.3 must be met under the conditions 
specified in S7.1 through S7.7. All measurements for calculating 
voltage(s) and electrical isolation are made after a minimum of 5 
seconds after the vehicle comes to rest in tests specified in S6. Where 
a range is specified, the vehicle must be capable of meeting the 
requirements at all points within the range.
    S7.1 Electric energy storage device state of charge. The electric 
energy storage device is at the state of charge specified in 
subparagraphs (a), (b), or (c), as appropriate:
    (a) At the maximum state of charge recommended by the manufacturer, 
as stated in the vehicle owner's manual or on a label that is 
permanently affixed to the vehicle;
    (b) If the manufacturer has made no recommendation in the owner's 
manual or on a label permanently affixed to the vehicle, at a state of 
charge of not less than 95 percent of the maximum capacity of the 
electric energy storage device; or
    (c) If the electric energy storage device(s) is/are rechargeable 
only by an energy source on the vehicle, at any state of charge within 
the normal operating voltage defined by the vehicle manufacturer.
    S7.2 Vehicle conditions. The switch or device that provides power 
from the high voltage system to the propulsion

[[Page 33528]]

motor(s) is in the activated position or the ready-to-drive position.
* * * * *
    S7.4 Rear moving barrier impact test conditions. In addition to the 
conditions of S7.1 and S7.2, the conditions of S7.3(b) and S7.6 of 
571.301 of this chapter apply to the conducting of the rear moving 
deformable barrier impact test specified in S6.2.
* * * * *
    S7.6 Electrical isolation test procedure. In addition to the 
conditions of S7.1 and S7.2, the conditions in S7.6.1 through S7.6.7 
apply to the measuring of electrical isolation specified in S5.3(a).
    S7.6.1 Prior to any barrier impact test, the high voltage source is 
connected to the vehicle's propulsion system, and the vehicle ignition 
is in the ``on'' (propulsion system energized) position. Bypass any 
devices or systems that do not allow the propulsion system to be 
energized at the time of impact when the vehicle ignition is on and the 
vehicle is in neutral. For a vehicle that utilizes an automatic 
disconnect between the high voltage source and the traction system that 
is physically contained within the high voltage electric energy 
storage/conversion/power generating system, the electrical isolation 
measurement after the test is made from the traction-system side of the 
automatic disconnect to the vehicle chassis electricity-conducting 
structure. For a vehicle that utilizes an automatic disconnect that is 
not physically contained within the high voltage electric energy 
storage/conversion/power generating system, the electrical isolation 
measurement after the test is made from both the high voltage source 
side and from the traction-system side of the automatic disconnect to 
the vehicle chassis electricity-conducting structure.
    S7.6.2 The voltmeter used in this test has an internal resistance 
of at least 10 M[Omega].
    S7.6.3 The voltage(s) is/are measured as shown in Figure 1 and the 
high voltage source voltage(s) (Vb) is/are recorded. Before any vehicle 
impact test, Vb is equal to or greater than the nominal operating 
voltage as specified by the vehicle manufacturer.
    S7.6.4 The voltage(s) is/are measured as shown in Figure 2, and the 
voltage(s) (V1) between the negative side of the high voltage source 
and the vehicle chassis electricity-conducting structure is/are 
recorded.
    S7.6.5 The voltage(s) is/are measured as shown in Figure 3, and the 
voltage(s) (V2) between the positive side of the high voltage source 
and the vehicle chassis electricity-conducting structure is/are 
recorded.
    S7.6.6 If V1 is greater than or equal to V2, insert a known 
resistance (Ro) between the negative side of the high voltage source 
and the vehicle chassis electricity-conducting structure. With the Ro 
installed, measure the voltage (V1') as shown in Figure 4 between the 
negative side of the high voltage source and the vehicle chassis 
electricity-conducting structure. Calculate the electrical isolation 
resistance (Ri) according to the formula shown. Divide Ri (in ohms) by 
the working voltage of the high voltage source (in volts) to obtain the 
electrical isolation (in ohms/volt).
    S7.6.7 If V2 is greater than V1, insert a known resistance (Ro) 
between the positive side of the high voltage source and the vehicle 
chassis electricity-conducting structure. With the Ro installed, 
measure the voltage (V2') as shown in Figure 5 between the positive 
side of the high voltage source and the vehicle chassis electricity-
conducting structure. Calculate the electrical isolation resistance 
(Ri) according to the formula shown. Divide Ri (in ohms) by the working 
voltage of the high voltage source (in volts) to obtain the electrical 
isolation (in ohms/volt).
    S7.7 Voltage measurement. For the purposes of determining low 
voltage source specified in S5.3(b), voltage is measured as shown in 
Figure 1. Voltage Vb is measured across the two terminals of the 
voltage source. Voltages V1 and V2 are measured between the source and 
the vehicle chassis electricity-conducting structure.
    S8 Test procedure for on-board electrical isolation continuous 
monitoring system. Prior to any impact test, the requirements of S5.4 
for the on-board electrical isolation continuous monitoring system 
shall be confirmed using the following procedure.
    (1) The electric energy storage device is at the state of charge 
specified in S7.1.
    (2) The switch or device that provides power from the high voltage 
system to the propulsion motor(s) is in the activated position or the 
ready-to-drive position.
    (3) Determine the isolation resistance, Ri, of the high voltage 
source with the electrical isolation monitoring system using the 
procedure outlined in S7.6.2 through S7.6.7.
    (4) Insert a resistor with resistance equal to Ro=1/(1/(95 times 
the working voltage of the high voltage source)--1/Ri) between the 
positive terminal of the high voltage source and the vehicle chassis 
electric conducting structure.

    The electrical isolation monitoring system indicator shall display 
a warning to the driver.

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    Issued: June 8, 2010.
David L. Strickland,
Administrator.
[FR Doc. 2010-14131 Filed 6-11-10; 8:45 am]
BILLING CODE 4910-59-C