Document ID: NHTSA-2007-28517-0001
Agency: nhtsa
Document Type: Rule
Title: Federal Motor Vehicle Safety Standards; Electric-Powered Vehicles: Electrolyte Spillage and Electrical Shock Protection
Posted Date: 2007-10-09T04:00Z

[Federal Register: October 9, 2007 (Volume 72, Number 194)]
[Proposed Rules]               
[Page 57260-57273]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr09oc07-22]                         

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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Part 571

[Docket No. NHTSA-2007-28517]
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: Notice of proposed rulemaking (NPRM).

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SUMMARY: Based on concern that the agency's standard on electric-
powered vehicles, as currently written, may inadvertently hinder the 
development of fuel cell vehicles in the United States, NHTSA is 
proposing to amend the electrical safety requirements of Federal Motor 
Vehicle Safety Standard (FMVSS) No. 305, Electric-powered vehicles: 
electrolyte spillage and electrical shock protection. The amendment 
would ensure that state-of-the-art fuel cell vehicles (FCVs) are 
consistent with the interests of safety and encompassed by FMVSS No. 
305 so that the market may continue to develop. This NPRM also proposes 
to harmonize FMVSS No. 305 with the revised FMVSS No. 301, as regards 
rear moving barrier impact test conditions. This rulemaking commenced 
in response to a petition from the Alliance of Automobile 
Manufacturers.

DATES: You should submit your comments early enough to ensure that 
Docket Management receives them not later than December 10, 2007. 
Proposed effective date of final rule: assuming that a final rule is 
issued, NHTSA proposes that the changes adopted by the rule would be 
mandatory for fuel cell vehicles manufactured on or after exactly one 
year from the date of publication of the final rule in the Federal 
Register, with optional early compliance.

[[Page 57261]]

ADDRESSES: You may submit comments [identified by DOT Docket ID Number 
NHTSA-2007-28517] by any of the following methods:
     Federal eRulemaking Portal: Go to http://www.regulations.gov.
 Follow the online instructions for submitting 

comments.
     Mail: Docket Management Facility: U.S. Department of 
Transportation, 1200 New Jersey Avenue, SE., West Building Ground 
Floor, Room W12-140, Washington, DC 20590-0001.
     Hand Delivery or Courier: West Building Ground Floor, Room 
W12-140, 1200 New Jersey Avenue, SE., between 9 a.m. and 5 p.m. ET, 
Monday through Friday, except Federal holidays.
     Fax: 202-493-2251.
    Instructions: For detailed instructions on submitting comments and 
additional information on the rulemaking process, see the Public 
Participation heading of the Supplementary Information section of this 
document. Note that all comments received will be posted without change 
to http://www.regulations.gov, including any personal information 

provided. Please see the Privacy Act heading below.
    Privacy Act: 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 you may visit http://DocketInfo.dot.gov
.

    Docket: For access to the docket to read background documents or 
comments received, go to http://www.regulations.gov or the street 

address listed above. Follow the online instructions for accessing the 
dockets.

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

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Background
II. Petitioner's Suggested Changes; NHTSA's Decisions on the 
Petition
    A. Fuel cell vehicles and FMVSS No. 305's isolation requirement
    B. Test Procedure Measurement Values
    C. Test Procedure Measurement Location on the Vehicle
    D. Setting 0.2 Joules as an Appropriate Low Energy Threshold
    E. Harmonizing FMVSS No. 305's Rear Impact Test Procedure with 
FMVSS No. 301
III. International Harmonization
IV. The Proposed Rule
V. Benefits/Costs
VI. Public Participation
VII. Rulemaking Analyses and Notices

I. Background

    Vehicles that use electricity as propulsion power can contain high 
voltage systems operating with several hundred volts at a time, as 
compared to conventional petroleum-powered vehicles, which usually 
contain only a 12-volt battery to power accessories like headlights, 
radios, and so forth. Thus, electric vehicles potentially pose 
electrical risks not posed by conventional petroleum-powered vehicles. 
During a crash, NHTSA requires electric vehicles to limit electrolyte 
spillage, retain energy storage devices, and maintain isolation between 
the vehicle's chassis and high-voltage system (49 Code of Federal 
Regulations (CFR) Part 571.305, ``Electric-powered vehicles: 
electrolyte spillage and electrical shock protection;'' also referred 
to as Federal Motor Vehicle Safety Standard (FMVSS) No. 305). 
Maintaining electrical isolation ensures that the high voltage system 
does not use the chassis itself to complete (or close) the circuit. 
This makes it less likely that a human or other object could touch the 
chassis and become part of the circuit, allowing electrical current to 
flow through them. FMVSS No. 305 is intended to protect occupants, 
rescue workers, or others who may come in contact with the vehicle 
after a crash from electrical shock hazards, by ensuring isolation of 
the vehicle's high voltage battery electrical system.
    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). SAE J1766 was first issued in 1996 and 
most recently updated in April 2005 in order to accommodate fuel cell 
vehicles (FCVs), based on concerns that SAE J1766 and FMVSS No. 305's 
electrical isolation requirements had not considered FCVs when they 
were originally developed.\1\
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    \1\ FMVSS No. 305 currently contains a 500 ohms/volt electrical 
isolation requirement, with isolation measured between the high 
voltage propulsion battery and the chassis. FCVs are designed with 
coolant loops to cool down very hot fuel cells during operation, and 
the coolant tends to become more conductive of electrical current 
over time, and able to convey electrical current to the vehicle 
chassis; i.e., the conductivity of the coolant causes the vehicle to 
be unable to maintain electrical isolation.
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    In order to bring FMVSS No. 305 back into line with the updates to 
SAE J1766, the Alliance of Automobile Manufacturers (``the Alliance'') 
petitioned NHTSA to conduct rulemaking to amend the requirements of 
FMVSS No. 305 so that FCV manufacturers would know the performance 
requirements required to comply with the FMVSSs and so that FCV 
development could proceed without hindrance. NHTSA is issuing this NPRM 
in order to promote our national policy goal of developing the hydrogen 
FCV market consistent with the interests of safety. The agency 
anticipates that current state-of-the-art FCVs, whether they contain AC 
or DC high voltage systems, will be able to meet the requirements of 
this proposed rule with virtually no design changes necessary.

II. Petitioner's Suggested Changes; NHTSA's Decisions on the Petition

    In this section, the preamble sets forth the petition's many 
suggested changes to FMVSS No. 305's requirements. These are marked in 
bullet format, and are followed by NHTSA's response to each suggested 
change. As will be discussed, NHTSA generally tentatively agrees with 
most of the petitioner's suggestions. To the extent the agency does not 
agree, the reasons for disagreeing are explained.
    NHTSA generally concurs with the petitioner's suggested amendments 
to FMVSS No. 305's requirements (except as noted) because the agency 
tentatively concludes that the changes would achieve the policy 
objective of aiding the development of the hydrogen FCV market 
consistent with the interests of safety. NHTSA agrees with the 
petitioner that not undertaking rulemaking could potentially interfere 
with development of the FCV market, as FCV manufacturers are currently 
uncertain of how to test electrical isolation in FCVs with liquid 
coolant loops.\2\ An additional benefit of this

[[Page 57262]]

rulemaking becoming final would be closer harmonization with 
international and voluntary industry consensus standards.
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    \2\ Under the current FMVSS No. 305, electrical isolation is 
measured only between the high voltage propulsion battery and the 
chassis, and functionally often ends up not being measured, because 
there is typically no voltage to be found downstream of the 
contactors that disconnect high voltage from the battery in the 
event of a crash. The proposed FMVSS No. 305 would measure 
electrical isolation between all high voltage sources and the 
chassis, clarifying vehicle manufacturers' obligations in terms of 
ensuring electrical isolation.
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 A. Fuel Cell Vehicles and FMVSS No. 305's Isolation Requirement

    FMVSS No. 305 currently requires an electrical isolation of 500 
ohms/volt.\3\ That isolation must be maintained between the vehicle's 
propulsion battery and chassis after frontal, side, and rear crash 
tests, and was based upon the shock hazard for alternating current 
(AC). The standard does not distinguish between AC and DC (direct 
current) types of electrical current. Also, the standard calculates 
isolation values using voltage readings only between the propulsion 
battery and the chassis, and not from other potential high voltage 
sources that may cause a shock hazard, such as fuel cells. Fuel cells 
and converters that change DC electrical current into AC to supply 
propulsion motors used in some electric-motor vehicle designs are not 
currently required to maintain electrical isolation from the chassis.
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    \3\ For the reader's reference, ohms are a measure of electrical 
resistance, or how much the material of an electrical circuit 
resists the flow of electricity (thus, a higher number indicates 
more resistance), and volts are a measure of voltage, or how much 
electrical potential there is between any two points in a circuit 
(or, how much force is required to push the electrical current 
through the circuit).
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     The petitioner states that the current 500 ohms/volt 
isolation requirement of FMVSS No. 305's paragraph S5.3 is not 
achievable for state-of-the-art FCVs, because they require a liquid 
coolant to dissipate the heat generated in the fuel cell, and the 
coolant itself is unavoidably an electrical conductor.\4\ The 
petitioner argues that the updated SAE J1766 allowance for an isolation 
level of 100 ohms/volt under certain defined conditions does not lower 
the level of safety currently provided by FMVSS No. 305, because it is 
well within the range of safety for DC current, and because the 
provision ``* * * is directly tied to a requirement to continuously 
monitor electrical isolation in service, with the obvious implication 
that driver warnings and other appropriate remedial actions will be 
taken if isolation drifts below the specified 100 ohms/volt level.''
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    \4\ SAE J1766 (rev. April 2005) states that ``The conductivity 
of [the aqueous] coolant is a key factor in the isolation 
characteristics of a fuel cell. Coolant conductance [of electrical 
current] increases with time which decreases isolation.''
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    NHTSA's response: We are proposing to set the electrical isolation 
for DC at 125 ohms/volt, not 100 ohms/volt.\5\ As noted above, FMVSS 
No. 305 currently requires 500 ohms/volt electrical isolation, which 
corresponds to 2 milliamps of body current for AC systems.\6\ To 
produce the same physiological effects (at least, before the onset of 
serious physical harm), the human body can withstand up to four times 
the amount of DC as AC. Thus, the DC current corresponding to the 
existing FMVSS No. 305 requirement for AC (2 milliamps) would be 2 x 4 
= 8 milliamps DC current. 8 milliamps of current corresponds to 125 
ohms/volt electrical isolation for DC, not 100 ohms/volt.\7\ This NPRM 
thus proposes to set the electrical isolation for DC at 125 ohms/volt.
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    \5\ It should be remembered that electrical isolation (ohms/
volt) is a measure of a material's resistance to electrical current 
passing through it: thus, a higher electrical isolation means that 
less current passes through.
    \6\ Based on Figure 1 in IEC-479, International Electrotechnical 
Commission, Technical Report: Effects of current on human beings and 
livestock--Part 1: General aspects (3rd ed., Sept. 1994). The agency 
received this as part of a presentation included in the Alliance's 
petition for rulemaking. Available for public viewing in the Office 
of Crashworthiness Standards, National Highway Traffic Safety 
Administration, 1200 New Jersey Avenue, SE., West Building, 
Washington, DC 20590.
    \7\ Based on Figure 2, id. The agency received this as part of a 
presentation included in the Alliance's petition for rulemaking. 
According to the same chart, 100 ohms/volt corresponds to 5 times 
the amount of DC as AC, which is beyond the accepted range of 
physical safety.
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B. Test Procedure Measurement Values

    The electrical isolation test procedure of FMVSS No. 305, contained 
in S7.6, essentially consists of: (1) Identifying the propulsion 
battery terminal that has the highest voltage differential between it 
and the vehicle chassis; (2) inserting a resistor of known value 
between that terminal and the vehicle chassis; and (3) measuring the 
voltage difference between the vehicle chassis and the battery 
terminal. With those measurements, the post-crash isolation resistance 
is determined according to a formula provided in the standard.
     The petitioner requested that FMVSS No. 305 be amended to 
recognize voltages of less than 60 VDC or 30 VAC as an appropriate way 
to provide electrical safety protection, as the revised SAE J1766 
already does. The Alliance pointed out that most electric vehicle 
designs use electrical contactors to disconnect high voltage from the 
propulsion battery in the event of a crash or other loss of isolation. 
Thus, they argued that the electrical isolation test procedure of FMVSS 
No. 305 is inappropriate for such designs, because the voltage 
differential between the high voltage system and the chassis would be 
zero, which would put a zero in the denominator of the equation to 
calculate isolation. The Alliance noted that FMVSS No. 305 does not 
recognize the absence of voltage as evidence of electrical safety, and 
therefore petitioned that the standard be revised to recognize voltages 
of less than 60 VDC or 30 VAC as an appropriate way to provide 
electrical safety protection.
    NHTSA's response: We agree that FMVSS No. 305 is not explicit that 
a voltage measurement of zero in the test procedure is evidence of 
electrical safety. We tentatively agree that it would be evidence of 
electrical safety, and are therefore proposing to change the test 
requirement in S5.3 from ``electrical isolation'' to ``electrical 
safety,'' so that ``electrical isolation'' becomes only one of the 
alternative requirements for ``electrical safety,'' along with a 
requirement that voltage between the vehicle chassis and the high 
voltage source be less than 60 VDC or 30 VAC. We believe that these 
changes would clarify the issue raised by the petitioner.
     The petitioner noted that NHTSA had previously expressed 
concern over the lack of a viable test procedure to test FCVs with 
hydrogen, but emphasized the importance of proceeding with this 
rulemaking in order not to hamper development of FCVs, and expressed 
its view that the test procedure was a detail that could be worked out 
later.
    NHTSA's response: The problem of not having a viable test procedure 
is that, for the safety of the testers, crash tests are generally 
performed with vehicles left unfueled or fueled with a less volatile 
alternative substance. However, FMVSS No. 305 and its formulas for 
calculating electrical isolation require that an electrical output 
measurement be available during the pretest and post-test phases of the 
various crash tests. Fuel cells without hydrogen, or filled with 
anything else,\8\ generate no electricity from which to measure 
electrical output. A determination as to whether FMVSS No. 305 will 
require further amendment to address FCV testing will await the results 
of ongoing research, and will not be addressed in this rulemaking.
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    \8\ Such as helium, as suggested by SAE J2578, ``Recommended 
Practice for General Fuel Cell Safety.''
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C. Test Procedure Measurement Location on the Vehicle

    FMVSS No. 305 (as well as previous versions of SAE J1766) currently 
requires the measurement of electrical isolation in only one location, 
between

[[Page 57263]]

the high voltage bus \9\ and the vehicle chassis. If a vehicle has 
electrical contactors located within the battery pack, this single 
measurement is taken between the downstream side of the contactor and 
the vehicle chassis.
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    \9\ A high voltage bus (or bus-bar) is a distribution location 
where multiple connections are made for the electrical circuits.
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     The petitioner requested that FMVSS No. 305 be amended to 
mirror the revised SAE J1766, which specifies several electrical 
isolation verification locations instead of just one: (1) Across the 
high voltage bus bar; (2) between the high voltage source and the 
vehicle chassis; (3) between the high voltage return and the vehicle 
chassis; and (4) between the conductive energy storage device and the 
vehicle chassis.
    NHTSA's response: We are proposing to change and add several 
definitions to FMVSS No. 305 in order to address this request. We agree 
that measurements should be taken from all high voltage sources for 
calculating electrical isolation from the vehicle chassis, because the 
risk of electric shock can come from any high voltage source and not 
just from the propulsion motor batteries. Additionally, we recognize 
that some electric-powered vehicles may have both AC and DC high 
voltage sources. Revised SAE J1766 added new definitions for energy 
storage devices, which take into consideration the fact that ultra-
capacitors \10\ have replaced propulsion batteries in some electric-
powered vehicle designs.
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    \10\ Ultra-capacitors act like batteries in that they store 
electrical energy and pose the same electrical safety hazards as 
batteries, except for electrolyte spillage.
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    We therefore propose to add a new definition to S4 of FMVSS No. 
305, to define ``high voltage source'' as either an electrical power-
generating device or an energy storage device that produces voltage 
levels equal to or greater than 30 VAC or 60 VDC.\11\ Other proposed 
changes to S4 include the addition of a definition for ``electrical 
isolation,'' to reflect that isolation measurements are to be taken 
between any high-voltage source and the vehicle's chassis; and the 
deletion of the existing definition for ``battery system component'' 
and its replacement with a definition for ``energy storage system'' 
which includes ultra-capacitors, high voltage batteries, and their 
associated hardware. Several other sections of FMVSS No. 305 would also 
be amended to reflect the changes proposed above.
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    \11\ We note that unlike SAE J1766, which specifies ``high-
voltage systems'' as greater than 60 VDC or 30 VAC, ECE R.100 
specifies high-voltage systems as greater than 60 VDC or 25 VAC. The 
AC high voltage value may eventually change in the final rule to 
make the definition consistent, pending the development of an 
internationally-consistent definition of high-voltage system through 
a global technical regulation (see discussion in Section III below, 
``International Harmonization'').
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D. Setting 0.2 Joules as an Appropriate Low Energy Threshold

     The petitioner requested that FMVSS No. 305 also be 
amended to mirror revised SAE J1766 insofar as that standard specifies 
an energy level below 0.2 joules as another appropriate way to provide 
electrical safety protection. The petitioner noted that the 0.2 joules 
of energy value specified in SAE J1766 was derived using data from the 
IEC 479-1 charts, and is non-harmful.\12\ The petitioner also noted for 
comparison that static electricity, which can involve voltages of more 
than 10,000 volts, is nevertheless benign to human health due to the 
low current and short durations associated with discharge.
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    \12\ This was based on 200 mA of current, with a duration of 10 
ms and a voltage of 200V with a safety factor of 2.
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    NHTSA's response: We are seeking comments on the inclusion of 0.2 
joules as an appropriate low energy threshold in FMVSS No. 305 to 
reflect that low amounts of electrical energy are acceptable. The 
agency remains less than fully convinced of the need for this 
amendment. The SAE's methodology, assuming a 10 ms duration of contact, 
does not seem realistic in the context of an automobile crash, and in 
fact would be much more typical as a result of static buildup than a 
fault contact with a high voltage electrical system after a crash.
    Additionally, NHTSA is concerned about the practicality of 
measuring a mere 0.2 joules of energy in a crash test environment. 
Comment to help the agency resolve this issue is requested.

E. Harmonizing FMVSS No. 305's Rear Impact Test Procedure With FMVSS 
No. 301

    The original version of FMVSS No. 305 \13\ incorporated the rear 
moving barrier test of FMVSS No. 301, Fuel System Integrity, which at 
the time was a 30 mph (48 km/h) test. In a 2004 final rule, response to 
petitions for reconsideration on FMVSS No. 301,\14\ the agency amended 
FMVSS No. 305 to give manufacturers the option of conducting either a 
rigid moving barrier 48-km/h test, or an upgraded-FMVSS No. 301 moving 
deformable barrier 80-km/h test. We stated that:
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    \13\ The final rule promulgating FMVSS No. 305 is available at 
65 FR 57980-57992 (Sept. 27, 2000).
    \14\ 69 FR 51393 (Aug. 19, 2004).

    Prior to the upgrade of the FMVSS No. 301 rear moving barrier 
impact test, compliance with the FMVSS Nos. 301 and 305 rear moving 
barrier requirements was based on similar test conditions and 
procedures. The similarity in test conditions gave manufacturers of 
gas-electric hybrid vehicles the opportunity to conduct one test 
instead of two to determine compliance with the two sets of rear 
impact requirements. Gas-electric hybrid vehicles with a GVWR of 
4,536 kg or less are subject to the rear moving impact requirements 
of both FMVSS Nos. 301 and 305, if they use both liquid fuel and 
more than 48 nominal volts of electricity as propulsion power. As a 
result of the FMVSS No. 301 upgrade, compliance with the FMVSS Nos. 
301 and 305 rear moving barrier requirements is no longer based on 
similar test conditions and procedures. The differences in the 
conditions and procedures could eliminate the opportunity to conduct 
one test instead of two for gas-electric hybrid vehicles. To 
reinstate the opportunity to conduct two tests instead of one, we 
are amending FMVSS No. 305 to permit compliance with the electrolyte 
spillage, battery retention and electrical isolation rear moving 
barrier impact requirements of FMVSS No. 305 under the upgraded 
FMVSS No. 301 rear moving barrier test conditions.\15\
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    \15\ Id., at 51396.

     The petitioner requested that the rear impact test speed 
of FMVSS No. 305 should be amended to correspond with the 80 km/h speed 
now required by FMVSS No. 301. The petitioner also stated that this 
would align FMVSS No. 305 with the recently amended Canadian Motor 
Vehicle Safety Standard 305, which requires the 80 km/h speed for 
vehicles produced after September 1, 2009.
    NHTSA's response: We are proposing to amend FMVSS No. 305 to 
specify only the 80 km/h test. NHTSA agrees that the rear test speed 
for FMVSS No. 305 should reflect the speed required in FMVSS No. 301, 
which is currently being phased in and will be required for all 
vehicles with liquid fuel systems manufactured after September 1, 2009. 
As noted by the Alliance, this change would also facilitate 
harmonization with Canadian Standard 305. Therefore, NHTSA proposes to 
amend FMVSS No. 305 to specify only the 80 km/h rear impact test, with 
S6.2 and S7.4 changed accordingly.

III. International Harmonization

    As long as safety is preserved, NHTSA believes that the same 
voltage should be used worldwide to denote high voltage systems, 
because vehicle manufacturers (and ultimately, consumers) can expect to 
achieve cost savings through the harmonization of different sets of 
standards. However, NHTSA is not ready just yet to harmonize fully with 
other international standards. Globally, there are several existing 
regulations and standards that pertain to high voltage systems in 
electric-powered

[[Page 57264]]

motor vehicles. The agency has been collaborating with the 
international community to develop a global technical regulation (GTR) 
for hydrogen-powered motor vehicles through its active participation in 
the United Nations World Forum for the Harmonization of Vehicle 
Regulations (WP.29). It has been agreed by WP.29 that a GTR be 
developed for hydrogen-powered motor vehicles. The United States, 
Germany, and Japan as sponsors have completed development of an action 
plan that outlines the key safety areas of hydrogen and FCVs for the 
GTR. The definition of high voltage systems in automobiles would likely 
be part of the development of this GTR.
    The existing requirements in the European regulation, ECE R.100, 
``Uniform provisions concerning the approval of battery electric 
vehicles with regard to specific requirements for the construction, 
functional safety and hydrogen emission,'' specify that battery-powered 
electric vehicles must maintain 500 ohms/volt electrical isolation 
between the propulsion battery and the vehicle chassis. This is similar 
to the requirement in FMVSS No. 305. NHTSA is aware that the ECE is 
currently considering changing this requirement to meet a 100 ohms/volt 
electrical isolation between the high voltage system and the vehicle 
chassis, without distinguishing between AC (greater than 25 volts) or 
DC (greater than 60 volts) electrical current. The ECE's draft 
amendments also allow for up to 10 milliamps of continuous electrical 
current or 100 ohms/volt of resistance. NHTSA has also examined the 
recent Japanese regulation TRIAS 11-1-4-101, ``Technical Standard for 
Protection of Occupants Against High Voltage in Fuel Cell Vehicles,'' 
which requires 100 ohms/volt electrical isolation between the chassis 
and the high-voltage system of those vehicles whose operating voltage 
is greater than 60 VDC.
    Despite our interest in international harmonization, NHTSA does not 
believe that allowing 10 milliamps of continuous electrical current is 
sufficiently safe. Even for a duration of 2 seconds, 10 milliamps of AC 
electrical current could result in a reversible disturbance in the 
heart (such as atrial fibrillation and transient cardiac arrest without 
ventricular fibrillation).\16\ Because of this, NHTSA is not proposing 
any changes to the existing isolation requirements for AC high voltage 
sources. Similarly, NHTSA does not believe that a change from the 
existing ECE requirement of 500 ohms/volt isolation to a requirement of 
100 ohms/volt isolation, without distinguishing between AC and DC 
current, would be consistent with the best interests of safety. 
Additionally, neither the Alliance petition nor the revised SAE J1766 
recommend any changes to the existing requirement of 500 ohms/volt 
isolation between AC high voltage sources and the chassis. Public 
comment is requested on the above values for electrical isolation and 
continuous current.
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    \16\ IEC 479-1, Table 4--Time/current zones for a.c. 15 Hz to 
100 Hz, p. 41.
---------------------------------------------------------------------------

IV. The Proposed Rule

A. Amending FMVSS No. 305 To Accommodate Fuel Cell Vehicles

    This NPRM proposes to amend FMVSS No. 305 by revising certain 
sections in order to realign the standard with the April 2005 update of 
SAE J1766 that was changed to accommodate fuel cell vehicles and avoid 
hindering the development of that market. The following points 
highlight the key provisions of the proposed requirements:
     The NPRM would change the applicability of FMVSS No. 305 
to accommodate state-of-the-art FCVs that use 60 VDC or 30 VAC or more 
for propulsion power instead of the existing 48 nominal volts.
     The NPRM would distinguish between isolation values for DC 
and AC currents, setting the value for DC high-voltage systems at 125 
ohms/volt.
     The NPRM would accommodate current FCV technology by 
changing the test requirement in S5.3 from ``electrical isolation'' 
alone to ``electrical safety,'' which would also include an alternative 
requirement that the voltage between the high-voltage source and the 
vehicle chassis be less than 60 VDC or 30 VAC.
     The NPRM would add a definition for ``high-voltage 
source,'' and amend the definition for ``electrical isolation'' to 
reflect that isolation measurements shall be taken from any high-
voltage source and the vehicle's chassis, instead of from only one 
location.
     The NPRM would harmonize S6.2 and S7.4 of FMVSS No. 305 
with the revised FMVSS No. 301, as regards rear moving barrier impact 
test conditions.

B. Effective Date

    NHTSA here proposes that the effective date of this rulemaking 
apply to vehicles manufactured one year after the final rule is 
published, with optional early compliance. The agency believes 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. 
Currently, all manufacturers of electric-powered vehicles already 
isolate the high voltage sources from the vehicle chassis.

IV. Benefits/Costs

    NHTSA anticipates no quantifiable economic or fatality-reduction 
benefits from this proposed rule. The update to FMVSS No. 305 
represents an increase in the stringency of the level of safety 
provided by the standard for FCVs that are currently in development but 
not yet on the roads. Because the safety benefits will be in the 
future, they are not currently quantifiable. Immediate benefits that 
will likely accrue are primarily of a policy nature: That the hydrogen 
FCV market will not be hindered in its continuing development, as the 
petitioner asserted; that various small inconsistencies that have 
lingered in the standard will be corrected; and so forth.
    NHTSA believes that the cost associated with this rulemaking would 
be negligible. Any added cost would consist only of what was involved 
in taking additional readings at different test points within vehicles 
that have both AC and DC power systems. Moreover, the vehicle 
manufacturers potentially affected by this proposed rule were involved 
in the update of SAE J1766 (which was revised to accommodate their 
current FCV designs), and are presumably already complying with that 
standard, so the additional cost of compliance with the proposed rule 
should be de minimis if not zero.

VI. Public Participation

How Do I Prepare and Submit Comments?

    Your comments must be written and in English. To ensure that your 
comments are filed correctly in the Docket, please include the docket 
number of this document in your comments.
    Your comments must not be more than 15 pages long (see 49 CFR 
553.21). We established this limit to encourage you to write your 
primary comments in a concise fashion. However, you may attach 
necessary additional documents to your comments. There is no limit on 
the length of the attachments.
    Please submit two copies of your comments, including the 
attachments, to Docket Management at the address given under ADDRESSES.
    You may also submit your comments to the docket electronically by 
logging onto the Dockets Management System website at http://dms.dot.gov.
 Click on

[[Page 57265]]

``Help & Information,'' or ``Help/Info'' to obtain instructions for 
filing the document electronically.

How Can I Be Sure That My Comments Were Received?

    If you wish Docket Management to notify you upon its receipt of 
your comments, enclose a self-addressed, stamped postcard in the 
envelope containing your comments. Upon receiving your comments, Docket 
Management will return the postcard by mail.

How Do I Submit Confidential Business Information?

    If you wish to submit any information under a claim of 
confidentiality, you should submit three copies of your complete 
submission, including the information you claim to be confidential 
business information, to the Chief Counsel, NHTSA, at the address given 
above under FOR FURTHER INFORMATION CONTACT. In addition, you should 
submit two copies, from which you have deleted the claimed confidential 
business information, to Docket Management at the address given above 
under ADDRESSES. When you send a comment containing information claimed 
to be confidential business information, you should include a cover 
letter setting forth the information specified in our confidential 
business information regulation (49 CFR part 512).

Will The Agency Consider Late Comments?

    We will consider all comments that Docket Management receives 
before the close of business on the comment closing date indicated 
above under DATES. To the extent possible, we also will consider 
comments that Docket Management receives after that date. If Docket 
Management receives a comment too late for us to consider it in 
developing the final rule, we will consider that comment as an informal 
suggestion for future rulemaking action.

How Can I Read The Comments Submitted By Other People?

    You may read the comments received by Docket Management at the 
address given under ADDRESSES. The hours of the Docket are indicated 
above in the same location.
    You also may see the comments on the Internet. To read the comments 
on the Internet, go to http://www.regulations.gov, and follow the 

instructions for accessing the Docket.
    Please note that even after the comment closing date, we will 
continue to file relevant information in the Docket as it becomes 
available. Further, some people may submit late comments. Accordingly, 
we recommend that you periodically check the Docket for new material.

VII. 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 proposed rule should 
have no significant effect on the national economy, and simply 
clarifies for FCV manufacturers their obligations under FMVSS No. 305.

B. Regulatory Flexibility Act

    Pursuant to the Regulatory Flexibility Act (5 U.S.C. 601 et seq., 
as amended by the Small Business Regulatory Enforcement Fairness Act 
(SBREFA) of 1996), whenever an agency is required to publish a notice 
of rulemaking for any proposed or final rule, it must prepare and make 
available for public comment a regulatory flexibility analysis that 
describes the effect of the rule on small entities (i.e., small 
businesses, small organizations, and small governmental jurisdictions). 
The Small Business Administration's regulations at 13 CFR part 121 
define a small business, in part, as a business entity ``which operates 
primarily within the United States.'' (13 CFR 121.105(a)). No 
regulatory flexibility analysis is required if the head of an agency 
certifies the rule will not have a significant economic impact on a 
substantial number of small entities. SBREFA amended the Regulatory 
Flexibility Act to require Federal agencies to provide a statement of 
the factual basis for certifying that a rule will not have a 
significant economic impact on a substantial number of small entities.
    NHTSA has considered the effects of this proposed rule under the 
Regulatory Flexibility Act. I certify that this proposed rule would not 
have a significant economic impact on a substantial number of small 
entities. Any small manufacturers that might be affected by this 
proposed rule are already subject to the requirements of FMVSS No. 305, 
and the testing costs added by this proposed rule are anticipated to be 
extremely small. Therefore, there should be only a very minor economic 
impact, if any.

C. Executive Order 13132 (Federalism)

    NHTSA has examined today's final rule pursuant to Executive Order 
13132 (64 FR 43255, August 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 federalism implications because 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.''
    Further, no consultation is needed to discuss the preemptive effect 
of today's rule. NHTSA rules can have preemptive effect in at least two 
ways. First, the National Traffic and Motor Vehicle Safety Act contains 
an express preemptive 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.'' 49 U.S.C. 30103(b)(1). It is this statutory 
command that preempts State law, not today's rulemaking, so 
consultation would be inappropriate.
    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.

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

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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, February 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) 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 preemptive 
effect of this rule is discussed above. NHTSA notes further that there 
is no requirement that individuals submit a petition for 
reconsideration or pursue other administrative proceeding 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 (Volume 65, Number 70; Pages 19477-78), or 
you may visit http://DocketInfo.dot.gov.

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 NPRM, nor 
would there be information collection requirements if this proposed 
rule were to be made final.

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 (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 a recent updating of SAE J1766. NHTSA is not, however, 
adopting SAE J1766 verbatim, for the reasons discussed in Section C(1) 
above, and is proposing an isolation level of 125 ohms/volt instead of 
100 ohms/volt for DC current. The agency believes that this will best 
avoid reducing the safety benefits of FMVSS No. 305 as it is currently 
written.
    NHTSA requests 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.''

List of Subjects in 49 CFR Part 565

    Imports, Motor vehicles, Motor vehicle safety, and Tires.

    In consideration of the foregoing, NHTSA proposes to amend 49 CFR 
Part 571.305 as follows:

PART 571--FEDERAL MOTOR VEHICLE SAFETY STANDARDS

    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.

    2. Amend Sec.  571.305 by revising S1, S2, S3, S4, 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, and S7.6.7 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 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 a crash which occur because of electrolyte spillage 
from energy storage devices, intrusion of energy storage device system 
components into the occupant compartment, and electrical shock.
    S3 Application. This standard applies to passenger cars, and to 
multipurpose passenger vehicles, trucks and buses with a GVWR of 4536 
kg or less, that use more than 60 volts direct current (VDC) or 30 
volts alternating current (VAC) of electricity as propulsion power and 
whose speed attainable over a distance of 1.6 km on a paved level 
surface is more than 40 km/h.
    S4 Definitions.
    Dummy means a 50th percentile male test dummy as specified in 
subpart F of part 572 of this chapter.
    Electrical isolation means the electrical resistance between the 
vehicle high-voltage source and any vehicle conductive structure.
    Energy storage system means the components comprising, but not 
limited to, the vehicle's high-voltage battery system or capacitor 
system. These include, but are not limited to, the battery or capacitor 
modules, interconnects, venting systems, battery or capacitor restraint 
devices, and energy storage boxes or containers that hold the 
individual battery or capacitor modules.
    High-voltage source means any item that produces voltage levels 
equal to or greater than 30 VAC or 60 VDC.
    VAC means volts of alternating current (AC).
    VDC means volts of direct current (DC).
* * * * *
    S5.2 Energy storage device retention. Energy storage system modules 
located inside the passenger compartment must remain in the location in 
which they are installed. Any energy storage system component that is 
located outside the passenger compartment must not enter the passenger 
compartment during the test procedures of S6 of this standard, as 
determined by visual inspection.
    S5.3 Electrical safety. After each test, electrical isolation and 
energy between any high-voltage source and the vehicle chassis 
electricity-conducting structure must meet the following:
    (a) For AC high-voltage systems, electrical isolation is not less 
than 500 ohms/volt; or

[[Page 57267]]

    (b) For DC high-voltage systems, electrical isolation is not less 
than 125 ohms/volt.
* * * * *
    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 Sec. 571.301 of this chapter 
and that is moving at any speed up to and including 80 km/h (50 mph) 
with dummies positioned in accordance with S6.2 of Sec. 571.301 of this 
chapter.
* * * * *
    S7 Test conditions. When the vehicle is tested according to S6, the 
requirements of S5 must be determined by the conditions specified in 
S7.1 through S7.6.7. All measurements for calculating electrical 
isolation or the amount of electrical energy will be made after a 
minimum of 5 seconds immediately after the 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 Energy storage device state of charge. The energy storage 
device is at the level specified in the following paragraphs (a), (b), 
or (c), as appropriate:
    (a) At the maximum state of charge recommended by the manufacturer, 
as stated in the vehicle operator's manual or on a label that is 
permanently affixed to the vehicle;
    (b) If the manufacturer has made no recommendation, at a state of 
charge of not less than 95 percent of the maximum capacity of the 
energy storage device; or
    (c) If the energy storage device(s) are rechargeable only by an 
energy source on the vehicle, at any state of charge within the normal 
operating voltage, as defined by the vehicle manufacturer.
    S7.2 Vehicle conditions. 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.
* * * * *
    S7.4 Rear moving barrier impact test conditions. In addition to the 
conditions of S7.1 and S7.2, the conditions of S7.5 and S7.6 of Sec. 
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.
    S7.6.1 Prior to any barrier impact test, the high-voltage system is 
connected to the vehicle's propulsion system, and the vehicle ignition 
is in the ``on'' (traction (propulsion) system energized) position. If 
the vehicle utilizes an automatic disconnect between the high-voltage 
system and the traction system that is physically contained within the 
high-voltage system, the electrical isolation measurement after the 
test is made from the traction system side of the automatic disconnect 
to the vehicle chassis. If the vehicle utilizes an automatic disconnect 
that is not physically contained within the high-voltage system, the 
electrical isolation measurement after the impact is made from the 
high-voltage source side of the automatic disconnect to the vehicle 
chassis.
    S7.6.2 The voltmeter used in this test has an internal resistance 
of at least 10 M[OHgr].
    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 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 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. 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. Calculate the electrical 
isolation (Ri) according to the formula shown.
    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. With the Ro installed, measure the voltage and record the 
voltage (V2') between the positive side of the high-voltage source and 
the vehicle chassis as shown in Figure 5. Calculate the electrical 
isolation (Ri) according to the formula shown.
* * * * *
    3. Further amend Sec.  571.305 by revising Figures 1, 2, 3, 4, and 
5 following S7.6.7 to read as follows:
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    Issued: October 2, 2007.
Stephen R. Kratzke,
Associate Administrator for Rulemaking.
[FR Doc. E7-19735 Filed 10-5-07; 8:45 am]

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