[Federal Register Volume 70, Number 172 (Wednesday, September 7, 2005)]
[Rules and Regulations]
[Pages 53079-53101]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-17661]


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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Parts 571 and 585

[Docket No. NHTSA 2005-22251]
RIN 2127-AJ70


Federal Motor Vehicle Safety Standards; Tire Pressure Monitoring 
Systems

AGENCY: National Highway Traffic Safety Administration, DOT.

ACTION: Final rule; response to petitions for reconsideration.

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SUMMARY: This document responds to petitions for reconsideration 
requesting changes in our April 8, 2005 final rule establishing a new 
Federal motor vehicle safety standard (FMVSS) requiring installation in 
new light vehicles of a tire pressure monitoring system (TPMS) capable 
of detecting when one or more of a vehicle's tires is significantly 
under-inflated. The petitions for reconsideration are granted in part 
and denied in part, and through this document, we are amending the 
standard and related provisions accordingly.

DATES: Effective Date: The amendments made in this final rule are 
effective October 7, 2005. Voluntary compliance is permitted 
immediately.
    Petitions for Reconsideration: If you wish to submit a petition for 
reconsideration for this rule, your petition must be received by 
October 24, 2005.

ADDRESSES: Petitions for reconsideration should refer to the docket 
number above and be submitted to: Administrator, Room 5220, National 
Highway Traffic Safety Administration, 400 Seventh Street, SW., 
Washington, DC 20590.
    See the SUPPLEMENTARY INFORMATION portion of this document (Section 
VI; Rulemaking Analyses and Notices) for DOT's Privacy Act Statement 
regarding documents submitted to the agency's dockets.

FOR FURTHER INFORMATION CONTACT: For non-legal issues, you may call Mr. 
George Soodoo or Mr. Samuel Daniel, Office of Crash Avoidance Standards 
(Telephone: 202-366-2720) (Fax: 202-366-4329).
    For legal issues, you may call Mr. Eric Stas, 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, 400 Seventh Street, SW., Washington, DC 20590.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Summary of Decision
II. Background
    A. The TREAD Act
    B. Rulemaking History Prior to the April 2005 Final Rule
    C. The April 8, 2005 Final Rule
III. Petitions for Reconsideration
IV. Discussion and Analysis
    A. Low Tire Pressure Warning Lamp Activation Requirements
    B. TPMS Malfunction Indicator Lamp (MIL) Activation Requirements
    1. What Constitutes a TPMS Malfunction?
    2. MIL Disablement
    C. Telltale Requirements
    D. Tire-Related Issues
    1. Spare Tires
    2. Tire Reserve Load
    3. Minimum Activation Pressure
    E. Owner's Manual Requirements
    1. Lead Time
    2. Content of Required Statement
    3. Other Owner's Manual Issues
    F. Test Procedures
    1. Test Conditions
    2. Vehicle Cool-Down Period
    3. 2-psi Adjustment (Temperature Correction)
    4. Calibration Time
    G. TPMS Reprogrammability
    H. Sharing of TPMS Servicing Information
    I. Phase-In Calculations
V. Benefits and Costs
VI. Rulemaking Analyses and Notices

I. Summary of Decision

    This document responds to 15 petitions for reconsideration related 
to our April 8, 2005 final rule \1\

[[Page 53080]]

establishing FMVSS No. 138, Tire Pressure Monitoring Systems. The 
petitioners raised a variety of issues, most of which involved requests 
for technical changes to the standard (see section IV of this document 
for a complete discussion of issues raised in the petitions and their 
resolution). We have decided to grant the petitions in part and to deny 
them in part.
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    \1\ 70 FR 18136 (April 8, 2005) (Docket No. NHTSA-2005-20586-1).
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    The following points highlight the amendments to Standard No. 138 
that we are adopting in response to the petitions for reconsideration 
of the April 8, 2005 final rule (excluding a few minor editorial 
changes).
    <bullet> We have decided to postpone the compliance date for the 
standard's required TPMS-related owner's manual statement until 
September 1, 2006 (Model Year 2007), thereby granting petitions' 
request for additional lead time to incorporate the required language 
into the vehicle owner's manual. We do not believe that extending the 
compliance date in this manner (consistent with a recommendation in one 
of the petitions) would result in any safety consequences. Delay of the 
owner's manual requirements would not impact the functioning of the 
TPMS or the warnings that it provides, and we expect that even before 
that date, TPMS-equipped vehicles would have some owner's manual 
statement presenting relevant information to the consumer.
    We specifically note that delay in the compliance date for the 
standard's owner's manual requirements does not impact vehicle 
manufacturers' responsibility to provide TPMSs complying with FMVSS No. 
138 on a schedule consistent with the phase-in commencing on October 5, 
2005, as set forth in the April 8, 2005 final rule.
    <bullet> The agency has decided to retain the final rule's 
requirement for the TPMS malfunction indicator lamp (MIL) to illuminate 
whenever there is a malfunction that affects the generation of 
transmission of control or response signals in the vehicle's tire 
pressure monitoring system. However, in response to petitions, we have 
decided to amend the standard's test procedures for malfunction 
detection to clarify that telltale lamps will not be disconnected 
because such malfunctions will be indicated during the bulb check(s) 
required under the standard. Specifically, we are amending S6(k) by 
adding the following statement: ``When simulating a TPMS malfunction, 
the electrical connections for the telltale lamps shall not be 
disconnected.''
    <bullet> The lack of synchronization between the timing of 
compliance for compliance under FMVSS No. 138 and the TPMS telltale 
requirements of FMVSS No. 101, Controls and Displays, have been 
remedied through an earlier amendment to FMVSS No. 101. Technical 
revisions to FMVSS No. 138 have also been made in light of recent 
amendments to FMVSS No. 101 that have resulted in a change in location 
of the TPMS telltale provisions from Table 2 to Table 1 of that 
standard.
    <bullet> In this rule, we are amending the regulatory text in FMVSS 
No. 138 to clarify that for a combined low tire pressure/TPMS 
malfunction indicator telltale, the same flashing/continuous-
illumination sequence is required for one or more malfunctions that may 
affect the system simultaneously.
    <bullet> The agency has decided to modify the standard's test 
procedures to reduce the current 2-psi pressure adjustment (below the 
TPMS activation threshold) to 1 psi. The 2-psi adjustment was intended 
to facilitate testing, but several petitioners expressed concern that a 
2-psi adjustment could allow TPMSs to achieve compliance with an under-
inflation detection capability of 30 percent or more. The agency 
anticipates that a 1-psi adjustment would continue to facilitate 
testing while maintaining the under-inflation level close to the 
standard's 25-percent under-inflation activation threshold.
    <bullet> In order to more clearly differentiate between the TPMS 
standard's two phase-in production periods which are of different 
lengths (i.e., almost 11 months vs. one year), we have decided to 
modify 49 CFR 585.66, Reporting Requirements, to differentiate the 
reports to be submitted to the agency for each of the two phase-in 
periods. As currently drafted, section 585.66(b)(1), Basis for 
Statement of Compliance, and section 585.66(b)(2), Production, require 
manufacturers to report values for the full production year, without 
mention of the period corresponding to the first period of the phase-in 
(i.e., from October 5, 2005 to September 1, 2006), which is the 
relevant total production value for calculation under S7.1(b) of FMVSS 
No. 138. Because the reporting of this information directly relates to 
determining compliance with the requirements of FMVSS No. 138, we have 
decided to revise 49 CFR 585.66(b)(1) and (2) to clearly differentiate 
between the two phase-in production periods.

II. Background

A. The TREAD Act

    Congress enacted the Transportation Recall Enhancement, 
Accountability, and Documentation (TREAD) Act of 2000 \2\ on November 
1, 2000. Section 13 of that Act \3\ required the Secretary of 
Transportation, within one year of the statute's enactment, to complete 
a rulemaking ``to require a warning system in new motor vehicles to 
indicate to the operator when a tire is significantly under inflated.'' 
Section 13 also required the regulation to take effect within two years 
of the completion of the rulemaking. Responsibility for this rulemaking 
was delegated to NHTSA.
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    \2\ Public Law 106-414, 114 Stat. 1800 (2000).
    \3\ See 49 U.S.C. 30123 note (2003).
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B. Rulemaking History Prior to the April 2005 Final Rule

    Since passage of the TREAD Act, FMVSS No. 138 has had a protracted 
regulatory history. In summary, the agency published a notice of 
proposed rulemaking (NPRM) \4\ on July 26, 2001, which was followed by 
a final rule \5\ published on June 5, 2002.
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    \4\ 66 FR 38982 (July 26, 2001) (Docket No. NHTSA-2000-8572-30).
    \5\ 67 FR 38704 (June 5, 2002) (Docket No. NHTSA-2000-8572-219).
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    After issuance of the June 2002 final rule, Public Citizen, Inc., 
New York Public Interest Research Group, and the Center for Auto Safety 
filed a suit challenging certain aspects of the TPMS regulation. The 
Court of Appeals for the Second Circuit (Second Circuit) issued its 
opinion in Public Citizen, Inc. v. Mineta \6\ on August 6, 2003. The 
Court found that the TREAD Act unambiguously mandates TPMSs capable of 
monitoring each tire up to a total of four tires, effectively 
precluding the one-tire, 30-percent under-inflation detection option in 
the June 5, 2002 final rule, or any similar option for a system that 
cannot detect under-inflation in any combination of tires up to four 
tires. Ultimately, the Court vacated the standard in its entirety and 
directed the agency to issue a new rule consistent with its August 6, 
2003 opinion. NHTSA published a final rule in the Federal Register on 
November 20, 2003, vacating FMVSS No. 138.\7\
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    \6\ 340 F.3d 39 (2d Cir. 2003).
    \7\ 68 FR 65404 (Nov. 20, 2003) (Docket No. NHTSA-2003-16524-1).
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    The agency commenced rulemaking efforts to re-establish FMVSS No. 
138 in a manner consistent with the Court's opinion and responsive to 
issues raised in earlier petitions for reconsideration, the majority of 
which remained relevant. To this end, the agency published a new NPRM 
\8\ on September 16, 2004.
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    \8\ 69 FR 55896 (Sept. 16, 2004) (Docket No. NHTSA-2004-19054-
1).

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[[Page 53081]]

    After carefully considering public comments on the NPRM, the agency 
published a final rule \9\ in the Federal Register on April 8, 2005, 
which re-established FMVSS No. 138, with a phase-in set to begin on 
October 5, 2005. (For a more complete discussion of this earlier period 
of the regulatory history of the TPMS rulemaking, readers should 
consult the June 5, 2002 final rule, the September 16, 2004 NPRM, and 
the April 8, 2005 final rule.)
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    \9\ 70 FR 18136 (April 5, 2005) (Docket No. NHTSA-2005-20586-1).
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C. The April 8, 2005 Final Rule

    As noted above, the April 8, 2005 final rule for TPMS re-
established FMVSS No. 138 in a manner consistent with the Second 
Circuit's opinion. Specifically, it requires passenger cars, multi-
purpose passenger vehicles, trucks, and buses with a GVWR of 4,536 kg 
(10,000 pounds) or less, except those with dual wheels on an axle, to 
be equipped with a TPMS to alert the driver when one or more of the 
vehicle's tires, up to all four of its tires, is significantly under-
inflated.\10\ Subject to the phase-in schedule and the exceptions 
below, the final rule mandated compliance with the requirements of the 
standard, commencing with covered vehicles manufactured on or after 
October 5, 2005 (i.e., MY 2006). The standard is intended to be 
technology-neutral, so as to permit compliance with any available TPMS 
technology that meets the standard's performance requirements.
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    \10\ There are two types of TPMSs currently available, direct 
TPMSs and indirect TPMSs. Direct TPMSs have a pressure sensor in 
each wheel that transmits pressure information to a receiver. In 
contrast, indirect TPMSs do not have tire pressure sensors, but 
instead rely on the wheel speed sensors, typically a component of an 
anti-lock braking system, to detect and compare differences in the 
rotational speed of a vehicle's wheels, which correlate to 
differences in tire pressure.
    We anticipate that new types of TPMS technology may be developed 
in the future that will be capable of meeting the standard's 
requirements. For example, such systems might incorporate aspects of 
both direct and indirect TPMSs (i.e., hybrid systems). In concert 
with TPMS suppliers, tire manufacturers might be able to incorporate 
TPMS sensors directly into the tires themselves. In issuing a 
performance standard, NHTSA is cognizant of and seeks to encourage 
technological innovation.
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    The following points highlight the key provisions of the April 8, 
2005 final rule.
    <bullet> The TPMS is required to detect and to provide a warning to 
the driver within 20 minutes of when the pressure of one or more of the 
vehicle's tires, up to a total of four tires, is 25 percent or more 
below the vehicle manufacturer's recommended cold inflation pressure 
for the tires, or a minimum level of pressure specified in the 
standard, whichever pressure is higher. These minimum activation 
pressures are included in Table 1 of FMVSS No. 138.
    <bullet> Vehicle manufacturers must certify vehicle compliance 
under the standard with the tires installed on the vehicle at the time 
of initial vehicle sale.\11\
    <bullet> The TPMS must include a low tire pressure warning telltale 
\12\ (yellow) that must remain illuminated as long as any of the 
vehicle's tires remain significantly under-inflated and the vehicle's 
ignition locking system is in the ``On'' (``Run'') position.\13\ The 
TPMS's low tire pressure warning telltale must perform a bulb-check at 
vehicle start-up.
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    \11\ We note that some vehicle manufacturers authorize their 
dealers to replace the vehicle's factory-installed tires with other 
tires, including ones with a different size and/or recommended cold 
tire inflation pressure. The TPMS must perform properly with any 
such tires, because the vehicle could be equipped with those tires 
at the time of initial sale. Of course, the manufacturer would not 
have that responsibility if the dealer installed other tires without 
manufacturer authorization.
    \12\ As part of this final rule, we added two versions of the 
TPMS low tire pressure telltale and a TPMS malfunction telltale to 
Table 2 of FMVSS No. 101, Controls and Displays (since changed to 
Table 1).
    \13\ We note that if a vehicle manufacturer elects to install a 
low tire pressure telltale that indicates which tire is under-
inflated, the telltale must correctly identify the under-inflated 
tire. (See S4.3.2, as contained in the April 8, 2005 final rule.)
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    <bullet> The TPMS must also include a TPMS malfunction indicator to 
alert the driver when the system is non-operational, and thus unable to 
provide the required low tire pressure warning.\14\ The TPMS 
malfunction indicator must detect a malfunction within 20 minutes of 
occurrence of a system malfunction and provide a warning to the driver. 
This final rule provided two options by which vehicle manufacturers may 
indicate a TPMS malfunction:
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    \14\ We note that the TPMS telltale(s) may be incorporated as 
part of a reconfigurable display, provided that all requirements of 
the standard are met.
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    (1) Installation of a separate, dedicated telltale (yellow) that 
illuminates upon detection of the malfunction and remains continuously 
illuminated as long as the ignition locking system is in the ``On'' 
(``Run'') position and the situation causing the malfunction remains 
uncorrected, or
    (2) Designing the low tire pressure telltale so that it flashes for 
a period of at least 60 seconds and no longer than 90 seconds when a 
malfunction is detected, after which the telltale must remain 
continuously illuminated as long as the ignition locking system is in 
the ``On'' (``Run'') position. This flashing and illumination sequence 
must be repeated upon each subsequent vehicle start-up until the 
situation causing the malfunction has been corrected.
    If the option for a separate telltale is selected, the TPMS 
malfunction telltale must perform a bulb-check at vehicle start-up.
    <bullet> The TPMS is not required to monitor the spare tire (if 
provided), either when it is stowed or when it is installed on the 
vehicle.
    <bullet> For vehicles certified under the standard, vehicle 
manufacturers must provide in the owner's manual a specified statement 
explaining the purpose of the low tire pressure warning telltale, the 
potential consequences of significantly under-inflated tires, the 
meaning of the telltale when it is illuminated, and what actions 
drivers should take when the telltale is illuminated. Vehicle 
manufacturers also must provide a specified statement in the owner's 
manual regarding: (1) Potential problems related to compatibility 
between the vehicle's TPMS and various replacement or alternate tires 
and wheels, and (2) the presence and operation of the TPMS malfunction 
indicator. For vehicles that do not come with an owner's manual, the 
required information must be provided in writing to the first purchaser 
at the time of initial vehicle sale.
    In terms of the timing for compliance, the final rule provided as 
follows. Subject to the vehicle manufacturer option for carry-backward 
credits discussed below, NHTSA decided to adopt the following phase-in 
schedule: 20 percent of a vehicle manufacturer's light vehicles are 
required to comply with the standard during the period from October 5, 
2005 to August 31, 2006; 70 percent during the period from September 1, 
2006 to August 31, 2007, and all light vehicles thereafter. Vehicle 
manufacturers are not required to comply with the requirements related 
to the TPMS malfunction indicator (including associated owner's manual 
requirements) until September 1, 2007; however, at that point, all 
covered vehicles must meet all relevant requirements of the standard 
(i.e., no additional phase-in for MIL requirements). The final rule 
included phase-in reporting requirements consistent with the phase-in 
schedule discussed above.
    Small volume manufacturers (i.e., those manufacturers producing 
fewer than 5,000 vehicles for sale in the U.S. per year during the 
phase-in period) are not subject to the phase-in requirements, but 
their vehicles must meet the requirements of the standard beginning 
September 1, 2007.

[[Page 53082]]

    Consistent with the policy set forth in NHTSA's February 14, 2005 
final rule \15\ on certification requirements for vehicles built in two 
or more stages and altered vehicles, final-stage manufacturers and 
alterers must certify compliance for all covered vehicles manufactured 
on or after September 1, 2008 (no phase-in). However, final-stage 
manufacturers and alterers may voluntarily certify compliance with the 
standard prior to this date.
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    \15\ 70 FR 7414 (Feb. 14, 2005) (Docket No. NHTSA-1999-5673-54).
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    NHTSA decided to permit vehicle manufacturers to earn carry-forward 
credits for compliant vehicles, produced in excess of the phase-in 
requirements and manufactured between the effective date of this rule 
and the conclusion of the phase-in. These carry-forward credits could 
be used during the phase-in, but they could not be used to delay 
compliance certification for vehicles produced after the conclusion of 
the phase-in. Except for vehicles produced by final-stage manufacturers 
and alterers (who receive an additional year for compliance), all 
covered vehicles must comply with FMVSS No. 138 on September 1, 2007, 
without use of any carry-forward credits.
    To further ease implementation, we decided to also provide carry-
backward credits, whereby vehicle manufacturers may defer compliance 
with a part or all of the certification requirements for the first 
period of the phase-in, provided that they certify a correspondingly 
larger percentage of vehicles under the standard during the second 
period of the phase-in.

III. Petitions for Reconsideration

    NHTSA received a total of 17 petitions for reconsideration of the 
April 8, 2005 final rule from: (1) The Alliance of Automobile 
Manufacturers (Alliance); (2) the Association of International 
Automobile Manufacturers, Inc. (AIAM); (3) BMW Group (BMW); (4) 
Continental Teves, Inc.; (5) EnTire Solutions, LLC (EnTire); (6) ETV 
Corporation Pty Limited (ETV); (7) European Tyre and Rim Technical 
Organisation (ETRTO); (8) Michelin North America, Inc. (Michelin); (9) 
M-Vision, Inc.; (10) NIRA Dynamics AB; (11) Public Citizen; (12) Rubber 
Manufacturers Association (RMA); (13) SmarTire Systems, Inc. 
(SmarTire); (14) Specialty Equipment Market Association (SEMA); (15) 
Sumitomo Rubber Industries (SRI); (16) Tire Industry Association (TIA); 
and (17) Volkswagen/Audi (VW/Audi). All of these petitions may be found 
in Docket No. NHTSA-2005-20586. (We note that Public Citizen withdrew 
its petition for reconsideration in a letter dated June 16, 2005,\16\ 
and TIA withdrew its petition for reconsideration in a letter dated 
July 28, 2005.\17\ Consequently, we are not discussing these two 
petitions further in this document.)
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    \16\ Docket No. NHTSA-2005-20586-31.
    \17\ Docket No. NHTSA-2005-20586-35.
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    The petitioners raised a variety of issues related to the TPMS 
standard, most of which were technical. These issues included ones 
involving the final rule's requirements for the under-inflation 
detection level, the under-inflation and malfunction detection times, 
functioning of the TPMS with spare tires, tire reserve load, compliance 
testing conditions and procedures, system disablement and 
reprogrammability, telltale issues, breadth of the malfunction 
detection requirement, minimum activation pressure, owner's manual 
requirements, sharing of TPMS servicing information, and phase-in 
calculations.
    All of the issues raised in the petitions for reconsideration 
presently before us are addressed in the Discussion and Analysis 
section immediately below.
    Effective Date. In light of the rapidly approaching October 5, 2005 
start of the phase-in for FMVSS No. 138, we find that there is good 
cause to make these amendments effective 30 days after publication. The 
changes resulting from this final rule responding to petitions for 
reconsideration generally involve requested technical modifications and 
clarifications to the standard. We believe that vehicle manufacturers 
and other interested stakeholders would benefit from rapid 
implementation of these amendments. We note, however, that vehicle 
manufacturers may voluntarily comply with the requirements of this 
final rule immediately.

IV. Discussion and Analysis

A. Low Tire Pressure Warning Lamp Activation Requirements

    The April 8, 2005 final rule required that each TPMS-equipped 
vehicle must illuminate a low tire pressure warning telltale not more 
than 20 minutes after the inflation pressure in one or more of the 
vehicle's tires, up to a total of four tires, is equal to or less than 
either the pressure 25 percent below the vehicle manufacturer's 
recommended cold inflation pressure, or the pressure specified in the 
third column of Table 1 of the standard for the corresponding type of 
tire, whichever is higher. The low pressure telltale must continue to 
illuminate as long as the inflation pressure of the tire(s) remains 
below the activation threshold above and the ignition locking system is 
in the ``On'' (``Run'') position, or until the system is manually reset 
in accordance with the vehicle manufacturer's instructions. (See S4.2, 
as contained in the April 8, 2005 final rule.)
    Several petitioners requested that the agency modify the time 
period for the TPMS to detect and to provide a warning regarding 
significant under-inflation in one or more of a vehicle's tires. Some 
petitioners recommended a reduction in detection time (ETRTO, SmarTire 
Systems, ETV); others sought an increase in such time period (NIRA 
Dynamics, VW/Audi), and still another argued for some combination of 
the two (BMW).
    ETRTO argued that the decision in the final rule to set a 20-minute 
detection time requirement for the TPMS low tire pressure warning (an 
increase from the 10-minute detection time proposed in the NPRM) may 
compromise safety, because driving for an additional 10 minutes on a 
significantly under-inflated tire could cause that tire to further 
deflate, overheat, and fail. ETRTO cautioned that ``technical 
neutrality'' should not be permitted to surpass safety concerns. 
Accordingly, the ETRTO petition urged NHTSA to adopt an under-inflation 
detection time of 10 minutes, as proposed in the NPRM. ETRTO did not 
provide supporting data to demonstrate the extent of tire degradation 
that would result from the under-inflation detection time adopted in 
the final rule.
    In its petition, SmarTire Systems argued that repeated exposure of 
a tire to excessive heat build-up could cause cumulative deterioration 
of the tire's structural components, which could ultimately lead to 
tire failure. SmarTire Systems provided data intended to show that 
within 12 minutes of city driving (at approximately 30 mph) at a low 
ambient temperature, pressure build-up within a properly inflated tire 
is about 3 psi, resulting from temperature build-up within the tire. 
According to the petitioner, the longer detection time interval may 
exacerbate this phenomenon and could actually mask an under-inflation 
condition. SmarTire Systems argued that this situation potentially 
could have unintended consequences for testing, as well as negative 
safety implications. As a result, SmarTire Systems also recommended 
that the standard be modified to return to a 10-minute under-inflation 
time requirement, as originally proposed.

[[Page 53083]]

    ETV argued that in order to maximize safety, the standard should be 
amended to require a TPMS to detect low tire pressure and to provide a 
warning immediately upon vehicle start-up. In making this argument, ETV 
analogized to other vehicle safety systems (e.g., air bags, ABS/brakes, 
seat belts) that provide a warning while the vehicle is stationary or 
parked (i.e., before the driver moves the vehicle into traffic).
    An opposing viewpoint was presented in the petition submitted by 
NIRA Dynamics, which argued that the 20-minute under-inflation 
detection time for more than one tire is unnecessarily stringent in 
light of the circumstances that normally cause multiple-tire under-
inflation. According to the petitioner, under-inflation in multiple 
tires usually results from slow diffusion over many months (loss of 1-2 
psi per month), so 20-minute time requirements for TPMS calibration and 
under-inflation detection are not necessary. NIRA Dynamics also stated 
that indirect TPMSs update actual parameter values whenever a vehicle 
is driven (storing the latest values in memory when the engine is 
turned off). Therefore, the TPMS telltale would be expected to 
illuminate, regardless of the length of the last driving cycle, as soon 
as the accumulated driving time with an under-inflated tire is 
sufficiently long. Accordingly, NIRA Dynamics recommended that NHTSA 
increase the time period permitted for TPMS calibration and low 
pressure detection for multiple tires to one hour. The petitioner 
stated that such a change would permit the use of advanced indirect 
TPMS technologies, while maintaining the safety benefits of the 
standard. The petition of VW/Audi made an argument very similar to that 
of NIRA Dynamics on this point.
    BMW also expressed its expectation that a TPMS-equipped vehicle 
would not need to be driven continuously during a single trip in order 
to detect low tire pressure, but instead, cumulative driving time 
gathered over a number of shorter trips should be adequate to detect 
and warn about significant tire under-inflation. Therefore, BMW 
reasoned that the TPMS would be unlikely to need the fully allotted 
detection time in most cases.
    However, BMW recommended a slightly different solution from that 
proposed by NIRA Dynamics and VW/Audi. Specifically, BMW stated that 
NHTSA should revise the standard to require a 10-minute cumulative 
driving detection time for pressure loss in a single tire and a 60-
minute cumulative driving detection time for pressure loss in multiple 
tires, an approach that it believes would offer an equivalent or higher 
level of safety than the approach adopted in the final rule. 
Alternatively, BMW suggested that its approach be adopted as an 
optional means of compliance. BMW argued that its requested change also 
would make the standard more technology-neutral, because it stated that 
there are not any ``production-ready'' indirect TPMSs that can meet the 
standard's 20-minute detection requirement under all circumstances.
    NHTSA has carefully considered the arguments of petitioners seeking 
modifications to the standard's low tire pressure warning lamp 
activation requirements. In general, the petitioners reiterated 
arguments raised at previous stages of this rulemaking and did not 
provide any new information to support their positions. Thus, we have 
decided to retain the low tire pressure activation requirements 
(including those related to system calibration) set forth in the April 
8, 2005 final rule. Our reasoning is largely the same as expressed in 
that notice, which we summarize below.
    We continue to believe that a 20-minute time period for under-
inflation detection in one to four tires is appropriate, as is a 20-
minute time period for TPMS calibration. The low tire pressure lamp 
activation requirements reflect the agency's careful balancing of 
safety and practicability concerns viewed through the prism of 
available data.
    As we noted in the final rule, TPMSs were not developed to warn the 
driver of extremely rapid pressure losses that could accompany a 
vehicle encounter with a road hazard or a tire blowout. According to 
the tire industry, those types of events account for approximately 15 
percent of pressure loss cases.\18\ Presumably, a driver would be well 
aware of the tire problem in those situations, and the TPMS would 
provide little added benefit.
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    \18\ 67 FR 38704, 38728 (June 5, 2002) (Docket No. NHTSA-2000-
8572-219).
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    Instead, TPMSs' benefits lie in warning drivers when the pressure 
in the vehicle's tires is approaching a level at which permanent tire 
damage could be sustained as a result of heat buildup and tire failure 
is possible; this low level of inflation pressure generally results 
from a more measured pressure loss cause by a slow leak, defective 
valve, or diffusion. According to the tire industry, approximately 85 
percent of all tire pressure losses are slow air losses that occur over 
hours, weeks, or months of vehicle use.\19\ In those cases, a detection 
time of 20 minutes is not likely to pose a safety risk to the driving 
public.
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    \19\ Id.
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    The agency's tire research suggests that even in a 25-percent 
under-inflated condition, the vehicle can be operated safely for this 
detection period without an appreciable risk of permanent damage or 
tire failure. NHTSA conducted testing on a variety of Standard Load P-
metric tires at 20 psi with 100-percent load at 75 mph for 90 minutes 
on a dynamometer, and none of these tires failed.\20\ This testing led 
the agency to conclude that warnings at less severe conditions will 
give drivers sufficient time to check and re-inflate their vehicles' 
tires before the tires experience appreciable damage. Furthermore, 
analysis of public comments at the NPRM stage demonstrated that a 
detection time period shorter than 20 minutes could raise issues of 
detection accuracy for many systems, which could lead to false telltale 
illuminations (``nuisance warnings''), which in turn could negatively 
impact consumer acceptance of TPMSs.
---------------------------------------------------------------------------

    \20\ Id. at 38726.
---------------------------------------------------------------------------

    Petitioners advocating a shorter time period did not provide any 
countervailing data to substantiate their assertions that a 20-minute 
detection time for a significantly under-inflated tire would lead to 
tire damage or tire failure. Although manufacturers are encouraged to 
provide the low tire pressure warning as quickly as possible, we 
believe that a 20-minute detection time is unlikely to result in any 
adverse safety consequences.
    We also believe that a 20-minute detection time is consistent with 
our intention to articulate a standard that is practicable and 
technology-neutral. As noted in the final rule, we are aware of at 
least one indirect TPMS that is currently capable of meeting the 
standard's four-tire, 25-percent under-inflation detection requirement 
within 20 minutes,\21\ and we expect that with additional time and 
development, other indirect and hybrid systems also would be able to 
meet the requirements of the standard.
---------------------------------------------------------------------------

    \21\ Docket No. NHTSA-2004-19054-96.
---------------------------------------------------------------------------

    We are not adopting ETRTO's and SmarTire's recommendations to 
reduce the time period for under-inflation detection time to 10 minutes 
because our tire data suggest that such change is not required for 
safety and because it would likely decrease the number of technologies 
available for complying with the standard. The same reasoning applies 
to our decision to deny ETV's suggestion that the TPMS be required to

[[Page 53084]]

provide a low tire pressure warning upon vehicle start-up (i.e., before 
the vehicle is in motion).
    Furthermore, we have decided not to extend the low tire pressure 
detection time beyond 20 minutes for multiple-tire under-inflation, as 
requested by NIRA Dynamics, VW/Audi, and BMW. As explained in the final 
rule, we believe that adverse safety consequences could result if the 
low tire under-inflation detection time were to extend beyond 20 
minutes. As discussed in the final rule, available research suggests 
that average commuting times are less than 30 minutes in most 
cases.\22\ Many other trips, such as routine errands, may also involve 
drive times of less than 30 minutes. We expressed concerns that by 
increasing the low tire pressure detection time, it would be 
conceivable that consumers could be driving on significantly under-
inflated tires for a potentially extended period of time without 
receiving a warning from the TPMS.
---------------------------------------------------------------------------

    \22\ 70 FR 18136, 18148 (April 8, 2005) (Docket No. NHTSA-2005-
20586-1).
---------------------------------------------------------------------------

    We also expressed concern that extending the low tire pressure 
detection time beyond 20 minutes could be problematic in other 
situations. For example, where a tire is punctured by a nail or is 
otherwise damaged, it may experience a moderately rapid pressure loss. 
As to damaged tires experiencing a relatively less rapid pressure loss, 
research into the rate of temperature buildup shows that for constant 
load, pressure, and speed conditions, tires generally warmed up and 
stabilized their temperatures within 15 minutes; \23\ thus, the tire 
will rapidly reach a temperature that places stress on an under-
inflated tire. In such cases, we are concerned about delaying the 
warning to the driver for too long. Therefore, in the April 8, 2005 
final rule, we selected 20 minutes for the low tire pressure detection 
time, because we believed that it would maintain the utility of the 
TPMS and the safety benefits associated with that system.
---------------------------------------------------------------------------

    \23\ See June 5, 2002 comments of the RMA (Docket No. NHTSA-
2000-8011-64).
---------------------------------------------------------------------------

    We do not believe that the arguments presented by BMW and NIRA 
Dynamics regarding the cumulative nature of data gathering by the TPMS 
justifies changing the standard's low tire pressure detection time to 
one hour for multiple tires. We believe that a one-hour delay in 
warning the driver of significant tire under-inflation either when the 
system is new, reset, or reprogrammed is too long, particularly given 
that other systems can provide a warning more rapidly. BMW and NIRA 
Dynamics did not provide any data indicating that tires could be 
operated safely for one hour after reaching a level of inflation that 
is 25 percent below placard pressure. Thus, we are concerned that an 
increase in the detection time for multiple-tire under-inflation could 
decrease the safety benefits of the rule. The same logic applies to 
BMW's suggestion that the time for malfunction detection be increased 
to one hour, a request that we are also denying, because a 
malfunctioning TPMS may not be available to warn about a concurrent 
tire under-inflation problem.

B. TPMS Malfunction Indicator Lamp (MIL) Activation Requirements

1. What Constitutes a TPMS Malfunction?
    As part of the final rule establishing FMVSS No. 138, the TPMS-
equipped vehicle's MIL telltale must provide a warning to the driver 
not more than 20 minutes after the occurrence of a malfunction that 
affects the generation or transmission of control or response signals 
in the vehicle's TPMS. (See S4.4, as contained in the April 8, 2005 
final rule.) Paragraph S6(k) of the final rule's test procedures 
provides for the simulation of one or more TPMS malfunction(s) by 
disconnecting any electrical connection between TPMS components, or by 
installing a tire or wheel on the vehicle that is incompatible with the 
TPMS.
    The details as to exactly what constitutes a TPMS malfunction were 
among the most extensively discussed issues in the petitions for 
reconsideration. Many petitioners who discussed this issue generally 
sought clarification regarding whether a malfunction warning would be 
required under specific situations. The malfunction-related issues 
raised in these petitions are addressed below.
    The AIAM recommended amending S4.4(a) to narrow the definition of 
``TPMS malfunction'' to limit that term to conditions where proper 
power supply is maintained to the TPMS. According to the AIAM petition, 
the standard, as currently written, would require installation of 
another electronic control module (ECM) in addition to the TPMS ECM in 
order to solely monitor MIL telltale operations, a largely redundant 
feature that would use up limited space behind the dashboard.
    As its recommended solution, the AIAM recommended that the scope of 
S4.4(a) be limited to situations where the TPMS has power, which would 
allow the system to identify malfunctions in the TPMS ECM and 
components such as the wheel sensors, signal antennae, or the presence 
of incompatible tires. In its petition, the AIAM argued that an 
interruption of power to the ECM or to the telltale (or to the 
connection between the ECM and the telltale) would be identifiable by 
failure to illuminate the TPMS MIL during bulb check. The AIAM also 
recommended modifying S6(l) to incorporate these conditions or by 
having S6(k) exclude these conditions from the procedures for creating 
a simulated TPMS malfunction.
    The Alliance similarly argued in its petition that NHTSA should 
clarify that S6(k) of the test procedures, which permits 
``disconnecting the power source to any TPMS component,'' should not 
include disconnecting the power source to the telltale itself. The 
Alliance stated its belief that the telltale is an FMVSS No. 101 
component (not a ``TPMS component''), and that the situation where 
there is a loss of power to the telltale is already covered by the bulb 
check requirements in S4.3.3(a) or S4.4(b)(4)(i), thereby obviating the 
need for it to be covered under S4.4(a).
    The Alliance also recommended a minor editorial change in 
S4.4(b)(3) that would modify that provision to read as follows: 
``Continues to illuminate the TPMS malfunction telltale under the 
conditions specified in S4.4(a) * * *.'' The standard currently 
references ``S4.4.''
    EnTire Solutions argued that for TPMSs using Hardwired Vehicle 
Speed Input to the TPMS receiver, such input does not directly affect 
``the generation or transmission of control or response signals'' in 
the vehicle's TPMS, and disconnecting vehicle speed input would not 
involve an electrical connection between ``TPMS components'' as called 
out specifically in S6(k) of the FMVSS No. 138 test procedures. 
According to EnTire Solutions, disconnecting vehicle speed input is 
``impractical'' to diagnose since such a disconnect would not prevent 
the TPMS from providing under-inflation warnings while driving unless 
there are multiple problems with the system. Accordingly, EnTire 
Solutions requested clarification as to whether systems using Hardwired 
Vehicle Speed Inputs need to illuminate the TPMS MIL telltale upon 
disconnection of those inputs.
    EnTire Solutions also requested a clarification regarding paragraph 
S6(k) of the TPMS test procedures, which provides an instruction 
regarding ``disconnecting any electrical connection between TPMS 
components * * *.'' Specifically, the petitioner questioned whether the 
above language

[[Page 53085]]

refers to connector-level interconnects or individual wires.
    In its petition, EnTire Solutions stated that for systems using 
multiple ground paths for the receiver, it is ``impractical'' to 
diagnose a single ground path disconnection. EnTire Solutions 
recommended that the standard be amended to clarify that TPMS MIL 
activation will not be required in such cases. EnTire Solutions also 
asked if the system could be constructed such that the low pressure 
detection lamp could be illuminated by an auxiliary power source when 
the primary source is disconnected without illuminating the MIL. This 
question applies to low tire pressure telltales that indicate which 
tire is under-inflated and telltales that do not indicate which tire is 
under-inflated (i.e., the ISO lamp).
    NIRA Dynamics' petition argued that it is not possible for vehicle 
manufacturers to meet the final rule's certification requirement for 
the TPMS to be able to detect all replacement tires that are not 
compatible with the system, because it is not possible to know what 
tires will be offered in the future or how such tires will interact 
with current TPMSs. According to NIRA Dynamics, to make such a 
certification, vehicle manufacturers installing indirect TPMSs would be 
required to test their systems with all types of tires available on the 
market, both now and in the future, something which would not be 
possible for economic and practical reasons. Therefore, the petitioner 
recommended amending the final rule to state that the TPMS MIL 
requirements are limited to electrical and system transmission 
interruptions or failures that result in no sensor signal being sent to 
the TPMS control module.
    In its petition, SRI argued that there are other conditions, albeit 
rare, that could affect the performance of TPMSs even if the control or 
response signals are properly transmitted. For example, SRI stated that 
a direct TPMS may not recognize that it is transmitting incorrect 
pressure data due to a sensor failure, or an indirect TPMS may not 
recognize that the sensitivity of the TPMS is lower due to certain tire 
characteristics. SRI essentially agreed with the argument of NIRA 
Dynamics, arguing that analyzing the influence of all replacement tires 
on the TPMS would be just as difficult as requiring that the TPMS be 
compliant with all replacement tires.
    M-Vision's petition questioned whether the standard's requirements 
for malfunction detection would include instances where there is a 
mechanical failure of the TPMS, including ones resulting from a 
separation of the joint/mount between the sensor assembly and the 
wheel, or separation of parts from the sensor assembly. According to M-
Vision, a typical TPMS sensor weighs about 40 grams (1.41 ounces), and 
if such components come loose as a result of fatigue, they may generate 
high g-forces, cause internal damage to the tire, and ultimately lead 
to tire failure. The M-Vision petition also argued that a loose TPMS 
device rattling within the front wheel could lead to sudden wheel 
imbalance while the vehicle is in motion, potentially causing the 
driver to steer improperly. In order to prevent what it deems to be a 
significant safety risk, M-Vision recommended that the definition of a 
``TPMS malfunction'' be modified to include mechanical failures, as 
described in its petition.
    Continental Teves' petition requested clarification of that portion 
of S4.4(a), which requires the TPMS MIL to illuminate ``not more than 
20 minutes after occurrence of a malfunction that affects the 
generation of transmission of control or response signals in the 
vehicle's tire pressure monitoring system.'' (Emphasis added.) We 
understand Continental Teves to be arguing that there are other 
circumstances or factors that could ``affect'' the system (e.g., 
replacement tire construction) without preventing it from detecting and 
providing the requisite low tire pressure warning. Therefore, 
Continental Teves recommended changing the word ``affects'' to 
``inhibits'' in S4.4(a), which it argued is consistent with the purpose 
of the TPMS MIL to alert the driver when the system is not functional.
    Given that the TPMS MIL requirements were a relatively recent 
conceptual addition to FMVSS No. 138, it is not surprising that several 
petitioners requested clarification of those provisions. As noted 
above, such clarification requests included questions of coverage of 
specific potential malfunction, some of which the petitioners asserted 
could be difficult to detect. Our response, addressing these concerns 
about the standard's malfunction requirements, is provided below.
    In overview, we have decided to retain the final rule's requirement 
for the TPMS MIL to illuminate whenever there is a malfunction that 
affects the generation of transmission of control or response signals 
in the vehicle's tire pressure monitoring system. The agency continues 
to favor a broad detection requirement for the TPMS MIL and not one 
limited to specific malfunctions, because such restrictions would 
unnecessarily reduce the safety benefits of the TPMS. However, in 
response to petitions (AIAM, Alliance) and in light of our own prior 
statements, we have decided to amend the standard's test procedures for 
malfunction detection to explicitly state that telltale lamps will not 
be disconnected, because such malfunctions would be indicated during 
the bulb checks required under S4.3.3(a) and/or S4.4(b)(4). 
Consequently, the driver would be provided with information regarding 
the operability of the TPMS warning telltale(s) through alternative 
means.
    We believe that this clarifying change is consistent with the final 
rule. In that notice, we stated that ``the MIL should not be required 
to signal a burned out bulb as a TPMS malfunction, because that problem 
would already be identified during the check-of-lamp function at 
vehicle start-up.'' (70 FR 18136, 18151 (April 8, 2005)) It was not our 
intention to require a redundant system solely to monitor the TPMS 
telltale(s). Similarly, the check-of-lamp function would alert the 
driver of malfunctions pertaining to processes directly tied to 
operation of the TPMS telltale(s) that necessitate servicing. When the 
driver takes the vehicle to the repair facility, the problem should be 
diagnosed and corrected, even though it may not be the one anticipated 
(e.g., a problem with a wire rather than a burned out bulb). Thus, this 
subset of TPMS-related malfunctions would still be expected to be 
identified, but through a mechanism other than the MIL. Accordingly, we 
are amending S6(k) to delimit the types of system malfunctions that 
will be simulated during testing, consistent with the above. 
Specifically, we are adding the following statement to that paragraph: 
``When simulating a TPMS malfunction, the electrical connections for 
the telltale lamps shall not be disconnected.''
    Furthermore, in response to EnTire's requests for clarification 
regarding specific potential disconnections, we have decided that all 
electrically-powered components and devices that interface with the 
TPMS, including hardwired vehicle speed inputs, are potential 
candidates for disconnection under S6(k). Similarly, a single ground 
path in a multiple ground path system may be a candidate for 
disconnection during TPMS malfunction testing.
    We are denying NIRA Dynamics' request that the standard be amended 
to exclude incompatible aftermarket and replacement tires from the 
malfunctions that the TPMS malfunction indicator must be able to 
detect. As noted in the April 8, 2005 final rule, we believe that the 
ability of the TPMS malfunction indicator to detect incompatible tires 
is key to the long-term functionality of the

[[Page 53086]]

TPMS, and unless such a warning is provided, some drivers may lose the 
benefits of the system entirely. It is plainly foreseeable that most 
vehicles will outlast their original set of tires, so this requirement 
is necessary to ensure that consumers continue to receive the TPMS's 
important information related to low tire pressure.
    The petition of NIRA Dynamics did not provide data to demonstrate 
the nature or extent of indirect TPMSs' alleged problems related to 
detection of incompatible tires. We do not believe that manufacturers 
would have to test all tires in order to determine which tires are 
incompatible with a given system, as NIRA Dynamics has suggested. Our 
understanding is that indirect TPMSs detect low tire pressure by 
comparing the differences in the rolling radius of the tires (i.e., 
speed of the tires) and activating the low tire pressure telltale when 
the difference between wheel speeds reaches a certain pre-determined 
value. We further understand that for indirect TPMSs, incompatible 
tires are primarily tires with a relationship between rolling radius 
and tire pressure that is outside the range of the system or where the 
geometry of one tire is outside the tolerances of the system. In such 
cases, the TPMS must be able to distinguish between a tire with low 
pressure and one that is incompatible with the TPMS, and to then 
illuminate the MIL.
    In direct TPMSs, tire incompatibility is primarily associated with 
tire construction materials and their potential attenuation of radio 
frequency signals generated by the TPMS unit (sensor) inside the tire. 
Based upon all available information, we have decided that TPMSs should 
continue to be required to alert the driver of a variety of system 
malfunctions, including installation of incompatible aftermarket or 
replacement tires. We believe that this approach will ensure continued, 
long-term TPMS functionality, which is consistent with Congress' 
intention to improve tire and vehicle safety, as expressed in the TREAD 
Act.
    We have decided not to adopt M-Vision's recommendation that we 
amend the standard's malfunction detection requirement to specifically 
address mechanical failures of the system, such as a separation of 
wheel-mounted TPMS components. We believe that severe mechanical 
failures of TPMS wheel components would trigger the TPMS malfunction 
indicator in most cases, because a severe mechanical problem with a 
sensor would retard communications between the sensor and the receiver. 
In addition, it would be difficult to simulate a mechanical malfunction 
of a wheel component without dismounting the tire from the wheel, and 
potentially damaging the TPMS. Furthermore, we have not been presented 
with any data to demonstrate that mechanical failures, such as those 
described in the M-Vision petition, are likely to arise in actual 
vehicles or the consequences thereof. If situations involving 
mechanical failures of TPMS wheel components were to develop 
frequently, those types of potential TPMS failures may be determined to 
be defects, which would be properly addressed by NHTSA's Office of 
Defects Investigation.
    Regarding Continental Teves' recommendation for a wording change 
under the standard's malfunction detection requirement (S4.4), 
specifically to state that a malfunction ``inhibits'' rather than 
``affects'' the generation or transmission of control or response 
signals in the vehicle's TPMS, we have decided to deny that request. 
Overall, the rationale offered by Continental Teves in support of its 
recommended change to the definition of a TPMS malfunction was not 
cogent and seemed incomplete. For example, the petition mentioned a 
hybrid system, but it did not explain how it operates. We do not 
believe that the Continental Teves petition provides a sufficient basis 
to support its recommended change to the standard.
    We have decided to grant the Alliance's request for a technical 
change in S4.4(b)(3) that would modify that provision to read as 
follows: ``Continues to illuminate the TPMS malfunction telltale under 
the conditions specified in S4.4(a) * * *.'' Although we do not believe 
that the standard's current reference to S4.4 in that provision is 
likely to cause any confusion or additional burden, we agree that the 
Alliance's recommended specification is more precise.
2. MIL Disablement
    The final rule did not contain any provision for MIL disablement, 
and the preamble discussed the agency's rationale for not permitting 
system disablement (see section IV.C.2(c), as contained in the April 8, 
2005 final rule).
    In its petition, SEMA expressed support for the agency's decision 
in the final rule not to permit disablement of the TPMS malfunction 
indicator lamp. However, SEMA requested clarification as to whether the 
MIL may be disabled (made inoperative) for the purpose of replacing the 
TPMS with an equivalent aftermarket TPMS that also meets the 
requirements of the FMVSS No. 138. For example, SEMA suggested that a 
consumer may wish to ``upgrade'' the vehicle's TPMS in situations where 
that person encounters incompatible replacement tires. If disablement 
of the MIL were permitted for such replacement purpose, SEMA argues 
that it would alleviate SEMA's concerns that consumers will choose not 
to install aftermarket or replacement rims and tires because they would 
lose the benefits of the MIL or have to accept driving with the MIL 
illuminated. Thus, SEMA recommended that NHTSA clarify that it is 
permissible to make the TPMS inoperative in order to replace the system 
with another TPMS that is also compliant with FMVSS No. 138.
    We do not believe that it is necessary to amend the TPMS standard 
in order to permit suppliers and service technicians to install 
aftermarket components and systems that comply with FMVSS No. 138. This 
principle holds for our safety standards generally. We believe this 
approach is appropriate for the following reasons.
    By way of background, the disablement for repair/replacement 
concept is addressed in 49 U.S.C. 30122(b), which provides:

    A manufacturer, distributor, dealer, or motor vehicle repair 
business may not knowingly make inoperative any part of a device or 
element of design installed on or in a motor vehicle or motor 
vehicle equipment in compliance with an applicable motor vehicle 
safety standard prescribed under this chapter [49 U.S.C. 30101 et 
seq.] unless the manufacturer, distributor, dealer, or repair 
business reasonably believes the vehicle or equipment will not be 
used (except for testing or a similar purpose during maintenance or 
repair) when the device or element is inoperative.

    When an automotive service business brings a vehicle into its 
facility for repair, replacement, or servicing of vehicle systems or 
components, it stands to reason that certain operating components or 
systems may need to be disabled in order to effectuate those changes. 
Furthermore, while such changes are pending, we expect that the vehicle 
would not be engaged in on-road use. By the time the vehicle is again 
returned to on-road use, the business must ensure that aspects of the 
vehicle covered by applicable FMVSSs have been made inoperative. With 
that proviso, upgrades to the vehicle of the type mentioned by SEMA 
would be permissible, even if the standard does not explicitly state 
it.
C. Telltale Requirements
    The final rule requires each TPMS to include a low tire pressure 
warning telltale that is mounted inside the occupant compartment in 
front of and

[[Page 53087]]

in clear view of the driver and which is identified by one of the 
symbols for the ``Low Tire Pressure Telltale'' in Table 2 of FMVSS No. 
101, Controls and Displays. The low tire pressure warning telltale is 
required to illuminate under the conditions specified in S4.2 of FMVSS 
No. 138, and it must also perform a check of lamp function when the 
ignition locking system is activated to the ``On'' (``Run'') position 
or a position between ``On'' (``Run'') and ``Start'' that is designated 
by the manufacturer as a check position. (See S4.3, as contained in the 
April 8, 2005 final rule.)
    Under the final rule, the TPMS-equipped vehicle is also required to 
be equipped with a TPMS malfunction indicator (beginning September 1, 
2007). This malfunction indicator may be provided either through a 
separate, dedicated telltale or through a combined low tire pressure/
TPMS malfunction telltale. For the separate TPMS MIL, the telltale must 
be mounted inside the occupant compartment in front of and in clear 
view of the driver and be identified by the word ``TPMS,'' as described 
under ``TPMS Malfunction Telltale'' in Table 2 of FMVSS No. 101. The 
dedicated TPMS malfunction telltale is required to illuminate under the 
conditions specified in S4.4 of FMVSS No. 138 for as long as the 
malfunction exists, and it must also perform a check of lamp function 
when the ignition locking system is activated to the ``On'' (``Run'') 
position or a position between ``On'' (``Run'') and ``Start'' that is 
designated by the manufacturer as a check position. (See S4.4(b), as 
contained in the April 8, 2005 final rule.)
    If the vehicle manufacturer elects to provide a combination 
telltale, it must meet the requirements of S4.2 and S4.3, as discussed 
above, and also indicate a TPMS malfunction as follows. While the 
ignition locking system is activated to the ``On'' (``Run'') position, 
upon detection of a TPMS malfunction, the combination telltale must 
flash for a period of at least 60 seconds but no longer than 90 
seconds. After this period of prescribed flashing, the telltale must 
remain continuously illuminated as long as the malfunction exists and 
the ignition locking system is activated to the ``On'' (``Run'') 
position. This flashing and illumination sequence must be repeated each 
time the ignition locking system is activated to the ``On'' (``Run'') 
position until the situation causing the malfunction has been 
corrected. (See S4.4(c), as contained in the April 8, 2005 final rule.)
    As discussed below, the Alliance petition raised issues related to 
the operation of the TPMS related telltale(s), as well as the timing 
for implementing the telltale requirements. More specifically, the 
Alliance's petition sought clarification regarding how a combined TPMS 
telltale should operate when sequential malfunctions occur. The 
Alliance identified the following potential approaches: (1) Have one 
flashing sequence cover all TPMS malfunctions; (2) Have each 
malfunction trigger a separate warning, or (3) Extend the length of the 
flashing sequence to indicate more than one malfunction. The 
recommendation of the Alliance was to leave the choice among these 
approaches to vehicle manufacturer discretion.
    The Alliance also petitioned to correct what it perceives to be a 
lack of synchronization between the TPMS telltale requirements in FMVSS 
No. 138 and in FMVSS No. 101. Specifically, the Alliance stated that 
vehicle manufacturers have no compliance requirements vis-a-vis FMVSS 
No. 138 until October 5, 2005, but there is not any corresponding 
compliance date specified in FMVSS No. 101 regarding the TPMS-related 
symbols (which arguably results in a compliance date of April 8, 2005 
for those telltale symbols). According to the Alliance, failure to 
remedy this apparent oversight would negatively impact the voluntary 
introduction of TPMSs that are not certified to FMVSS No. 138, and the 
Alliance stated that substantial lead time is needed to incorporate 
such display changes. Therefore, the Alliance recommended adding two 
footnotes to Table 2 of FMVSS No. 101 that would exempt vehicles from 
compliance with the TPMS symbol requirements for vehicles whose TPMSs 
are not certified as compliant with FMVSS No. 138 during the phase-in 
period for that standard.\24\
---------------------------------------------------------------------------

    \24\ The Alliance recommended that the following statement be 
added to Footnote 9 of FMVSS No. 101 Table 2: ``Display requirements 
for Tire Pressure Monitoring System Malfunction Telltale are 
effective for vehicles manufactured on or after September 1, 2007.''
---------------------------------------------------------------------------

    The Alliance also recommended adding a new Footnote 10 to that 
table as follows: ``Display requirements of the low tire pressure 
telltale are mandatory only for vehicles compliant with the 
requirements of FMVSS No. 138 at the date of vehicle manufacture.''
    Regarding the issue of sequential (multiple) malfunctions, we have 
decided that for vehicles with a combined low tire pressure/malfunction 
warning indicator, the telltale must flash for a single period of at 
least 60 seconds but no longer than 90 seconds and then remain 
continuously illuminated. This sequence will serve to alert the driver 
to any and all TPMS malfunctions detected by the system. We believe 
that once a consumer is warned that a TPMS malfunction exists, that 
person would be expected to take the vehicle to a service professional 
to diagnose and correct the problem. This reaction is not likely to 
change depending upon the number of malfunctions, and at such time, we 
anticipate that all conditions impairing operation of the TPMS would be 
resolved. Furthermore, we have decided to specify how sequential 
malfunctions would be indicated in order to prevent confusion on the 
part of the consumer and to ensure that TPMSs provide a consistent 
message across the fleet. Accordingly, we have made minor technical 
changes to S4.4(c)(2) of the standard to clarify this matter.
    Regarding the issue of the coordination of the compliance dates for 
the requirement of FMVSS No. 138 and Table 2 of FMVSS No. 101, we agree 
that it was not the agency's intention to require vehicle manufacturers 
to comply with the requirements for the TPMS telltale(s) in advance of 
the requirements for the installation of FMVSS No. 138-compliant TPMSs 
themselves. Vehicle manufacturers are not required to install TPMSs 
until October 5, 2005, and compliance could potentially be postponed if 
they elect to use carry-backward credits. During the phase-in, 
manufacturers could install other TPMSs that are not necessarily 
compliant with FMVSS No. 138, so we would not expect those vehicles to 
comply with the TPMS-related requirements of FMVSS No. 101, although we 
would expect vehicles voluntarily certified to FMVSS No. 138 to also 
meet the requirements of FMVSS No. 101. Furthermore, the TPMS 
malfunction telltale is not required until September 1, 2007, a fact 
reflected in FMVSS No. 138 but not in FMVSS No. 101.
    During our consideration of these petitions for reconsideration, 
the agency published a final rule updating FMVSS No. 101 (70 FR 48295 
(August 17, 2005)).\25\ At that time, we were already aware of this 
synchronization issue. Therefore, in order to clarify the relationship 
between the TPMS-related requirements of FMVSS Nos. 138 and 101, we 
included an amendment in that final rule to modify the relevant table 
in FMVSS No. 101.
---------------------------------------------------------------------------

    \25\ Docket No. NHTSA-2005-22113-1.
---------------------------------------------------------------------------

    We note here that the above final rule for FMVSS No. 101 
reorganized that standard to some extent, and consequently, the TPMS 
telltale

[[Page 53088]]

provisions are now contained in Table 1, rather than Table 2. 
Accordingly, we are revising S4.3.1(b) and S4.4(b)(2) of FMVSS No. 138, 
in order to properly reference the TPMS-related provision of FMVSS No. 
101.
    Returning to our discussion of the three footnotes for the TPMS-
related telltales incorporated into FMVSS No. 101, these footnotes read 
as follows.
    Footnote 13, which is applied to the symbols and words for all 
three TPMS telltales (i.e., the combined telltale which does not 
indicate which tire is under-inflated, the combined telltale which does 
indicate which tire is under-inflated, and the dedicated TPMS MIL), 
provides, ``Required only for FMVSS compliant vehicles.'' Thus, if the 
vehicle is certified to FMVSS No. 138, the TPMS telltale in question 
must comply with the requirements in Table 2.
    Footnote 14, which applies only to the dedicated TPMS MIL telltale, 
makes clear that a separate telltale is not required; it states, 
``Alternatively, either low tire pressure telltale may be used to 
indicate a TPMS malfunction. See FMVSS 138.''
    Footnote 15 also applies only to the dedicated TPMS MIL, stating, 
``Required only for vehicles manufactured on or after September 1, 
2007.'' For vehicle manufacturers that elect to provide a separate 
telltale for the MIL, the telltale would need to display ``TPMS'' after 
that date. Again, vehicle manufacturers with vehicles certified to 
FMVSS No. 138 could voluntarily certify that they comply with the MIL 
requirements before that date, in which case they would be subject to 
this TPMS telltale requirement, if they chose to install a dedicated 
MIL telltale. Because the necessary changes have already been 
incorporated into FMVSS No. 101, no additional amendments to the 
regulatory text are required by this final rule on this issue.

D. Tire-Related Issues

1. Spare Tires
    The April 8, 2005 final rule does not require the TPMS to monitor 
the pressure in a spare tire (either compact or full-sized), either 
while stowed or when installed on the vehicle.
    In its petition, ETV expressed its opinion that the TREAD Act 
requires the TPMS to continuously monitor all four active tires at all 
times while the vehicle is being driven. ETV then argued that because 
the April 8, 2005 final rule does not require the spare tire (whether 
compact or full-size) to be equipped with a TPMS sensor (for direct 
systems), this would render the TPMS either entirely or partially 
inoperable, in contravention of the TREAD Act. Furthermore, ETV 
expressed concern that in such situations, the TPMS MIL may illuminate, 
thereby masking other tire or system faults. Accordingly, ETV 
recommended that the standard be amended to require the spare tire to 
be fitted with a TPMS sensor so that the TPMS may continue to function 
in compliance with the standard when a spare tire is in use.
    We have decided not to adopt ETV's recommendation that we modify 
the standard to require the TPMS to operate when a spare tire is 
installed on the vehicle. We came to this decision for a number of 
reasons, including the knowledge on the part of drivers that temporary 
tires are not intended for extended use, the fact that compact spare 
tires pose operational problems for both direct and indirect TPMSs, the 
disincentive for manufacturers to supply a full-size spare (or any 
spare tire) if TPMS compliance were required, and the increased cost of 
the rule, with little if any safety benefit, if a spare tire must be 
monitored. In fact, as the standard is currently written, illumination 
of the TPMS MIL when a spare tire is installed may have the beneficial 
effect of encouraging the driver to rapidly repair or replace the 
regular tire, thereby permitting the spare tire to be returned to 
emergency reserve status. As noted in the final rule, NHTSA will not 
conduct compliance testing under Standard No. 138 with spare tires 
installed on the vehicle.
2. Tire Reserve Load
    The April 8, 2005 final rule establishing FMVSS No. 138 does not 
include any separate requirements for tire reserve load beyond those 
already specified under our FMVSSs for tires.
    Consistent with the position in its earlier petition for rulemaking 
and its comments on the NPRM, the RMA argued that the April 8, 2005 
final rule for TPMS does not adequately protect motor vehicle operators 
from the risk of driving on significantly under-inflated tires, because 
it does not provide a warning when one or more of the vehicle's tires 
has insufficient pressure to carry the actual load on the tires. 
According to the RMA, the final rule's TPMS activation threshold fails 
to ensure that consumers will receive adequate warning before the 
tire's inflation pressure falls below the minimum level required to 
support the actual load (or if unknown, the maximum load) on the tire. 
The RMA did not provide any new data on this topic, and for the sake of 
brevity, it did not repeat in its petition all of its earlier arguments 
and reasoning as to the need for a tire reserve load. Instead, it 
incorporated its earlier submissions by reference.\26\ The RMA's 
petition repeated its earlier recommendation that NHTSA should 
establish a reserve load requirement to ensure that the tires can 
safely carry the vehicle maximum load (i.e., not drop below the minimum 
values presented in the load/pressure tables of the Tire and Rim 
Association (TRA) Year Book), when the vehicle's tires are under-
inflated by 25 percent.
---------------------------------------------------------------------------

    \26\ Specifically, the RMA referenced its submissions to Docket 
No. NHTSA-2000-8572 (entry numbers 116, 172, 228, 238, 241, 260, 
261, 262, 263, and 271) and to Docket No. NHTSA-2004-19054 (entry 
number 34).
---------------------------------------------------------------------------

    ETRTO made essentially the same arguments as the RMA regarding the 
need for a tire reserve load requirement, in order to maximize consumer 
safety as required under the TREAD Act. We note that the RMA and ETRTO 
petitions for reconsideration provided no new data on the tire reserve 
load issue.
    We have decided to deny RMA's and ETRTO's request that we establish 
a tire reserve load requirement, based upon the reasoning cited in 
earlier agency pronouncements on this issue, as summarized below. In a 
notice published in the Federal Register on May 19, 2005, the agency 
denied the RMA's petition for rulemaking seeking to establish its 
recommended tire reserve load because neither the RMA's nor the 
agency's data demonstrated a safety need for such a requirement.\27\ 
Specifically, the available evidence did not demonstrate a reliable or 
conclusive relationship between tires with little or no pressure 
reserve and a higher rate of tire failures in the field. For a more 
complete discussion of the tire reserve load issue, please consult the 
above-referenced notice responding to the RMA petition.
---------------------------------------------------------------------------

    \27\ 70 FR 28888 (May 19, 2005) (Docket No. NHTSA-2005-20967-8).
---------------------------------------------------------------------------

    We further believe that the tire reserve load requirement requested 
by the RMA and ETRTO is unnecessary in light of certain other 
requirements in our tire standards. By way of explanation, FMVSS No. 
110, Tire Selection and Rims, mandates, among other things, that all 
passenger cars sold in the United States be equipped with tires that 
are capable of carrying the vehicle's maximum loaded vehicle weight at 
the manufacturer's recommended cold inflation pressure (vehicle placard 
pressure). Multipurpose passenger vehicles, trucks, buses and trailers 
must be fitted with tires that are capable of supporting the vehicle's 
gross axle

[[Page 53089]]

weight rating (GAWR).\28\ In most cases, vehicle manufacturers meet 
these requirements by consulting standardized tables for tire size, 
loading, and inflation pressure published by the Tire and Rim 
Association or other international tire industry organizations.\29\
---------------------------------------------------------------------------

    \28\ This requirement was adopted from FMVSS No. 120, Tire 
Selection and Rims for Motor Vehicles Other Than Passenger Cars. 
Before TREAD Act-related upgrades were made (which also consolidated 
NHTSA's tire standards), passenger cars, and non-passenger cars 
regardless of their gross vehicle weight rating (GVWR), were covered 
by FMVSS Nos. 110 and 120 respectively.
    \29\ Paragraph S4.3.1(c) of FMVSS No. 110 permits the use of 
standard tire pressure/load tables contained in publications listed 
in paragraph S4.4.1(b) of FMVSS No. 109 that are current at the date 
of manufacture of the tire or any later date. Specifically, 
publications by any of the following international industrial 
organizations may be used: (1) The Tire and Rim Association, (2) The 
European Tyre and Rim Technical Organization, (3) Japan Automobile 
Tire Manufacturers' Association, Inc., (4) Tyre & Rim Association of 
Australia, (5) Associacao Latino Americana de Pneus e Aros Brazil), 
or (6) The South African Bureau of Standards.
---------------------------------------------------------------------------

    Vehicle manufacturers may, at their discretion, specify a higher 
placard pressure for the tires fitted to their products than that 
provided by the TRA tables to support the vehicle's maximum load. This 
additional tire pressure is known as ``tire pressure reserve.'' Within 
bounds, an increase in tire pressure results in an increase in load 
carrying capacity. The extra load carrying capacity realized, because 
of the additional tire pressure, is called the ``tire load reserve.''
    As noted in our denial of the RMA's petition, we believe that the 
existing requirements in our tires standards provide an adequate 
pressure reserve. FMVSS No. 110 also includes a requirement for a tire 
pressure reserve based on vehicle normal load.
    ``Vehicle normal load'' is that load on an individual tire that is 
determined by distributing to each axle its share of the curb weight, 
accessory weight, and occupant weight and dividing the result by two. 
The number of occupants used to determine the ``normal load'' is 
defined in FMVSS No. 110 as two persons for a vehicle with four seating 
positions, and three persons for a vehicle with five seating positions. 
The current standard requires that the vehicle normal load on a tire 
shall not be greater than 88 percent of the tire's maximum load rating 
as marked on the tire sidewall.
    NHTSA published a final rule upgrading the standards applicable to 
tires on June 26, 2003.\30\ The upgraded version of FMVSS No. 110 
specifies that the vehicle normal load on each tire must not exceed 94 
percent of the tire's load rating at the placard pressure for that 
tire. This change in calculation of vehicle normal load is intended to 
more accurately reflect the load based on the vehicle's placard 
pressure, which may vary from vehicle to vehicle, even when the same 
tires are used. We anticipate that this change may result in a placard 
pressure increase of 1-2 psi.\31\
---------------------------------------------------------------------------

    \30\ The June 23, 2003 final rule pertained to FMVSS No. 109, 
New Pneumatic Bias Ply and Certain Specialty Tires, FMVSS No. 110, 
Tire Selection and Rims for Motor Vehicles with a GVWR of 4,536 
Kilograms (10,000 Pounds) or Less, FMVSS No. 119, New Pneumatic 
Tires for Motor Vehicles with a GVWR of More Than 4,536 Kilograms 
(10,000 Pounds) and Motorcycles, FMVSS No. 120, Tire Selection and 
Rims for Motor Vehicles with a GVWR of More Than 4,536 Kilograms 
(10,000 Pounds), and FMVSS No. 139, New Pneumatic Radial Tires for 
Light Vehicles. See 68 FR 38116 (June 23, 2003) (Docket No. NHTSA-
2003-15400-1).
    \31\ The agency has conducted a FMVSS No. 110 vehicle normal 
load evaluation and has concluded that almost all light vehicles 
could meet a revised criteria for load reserve based on 94 percent 
of placard pressure with only a minor increase (e.g., 1 or 2 psi) in 
inflation pressure to accommodate the new requirement. Id. at 38141.
---------------------------------------------------------------------------

3. Minimum Activation Pressure
    Under S4.2 of the standard, the TPMS must illuminate a low tire 
pressure warning telltale not more than 20 minutes after the inflation 
pressure in one or more of the vehicle's tires, up to a total of four 
tires, is equal to or less than either the pressure 25 percent below 
the vehicle manufacturer's recommended cold inflation pressure, or the 
pressure specified in the 3rd column of Table 1 of the standard for the 
corresponding type of tire, whichever is higher. Table 1 is titled 
``Low Tire Pressure Warning Telltale--Minimum Activation Pressure'' 
(MAP). The third column of Table 1 specifies the following MAP values: 
(1) P-metric, Standard Load (140 kPa/20 psi); (2) P-metric, Extra Load 
(160 kPa/23 psi); (3) Load Range C (200 kPa/29 psi); (4) Load Range D 
(240 kPa/35 psi); and (5) Load Range E (240 kPa/35 psi).
    The Alliance acknowledged the modifications to the MAP values in 
the final rule as an improvement over the values proposed in the NPRM. 
However, the Alliance nevertheless recommended that the standard should 
be modified further to permit light truck Load Range D and E tires to 
be used across the safe operating range of inflation pressures for 
those tires that are specified in the load/pressure tables of the TRA 
Year Book. According to the Alliance, TPMSs require a 7 to 10 psi 
differential between recommended cold inflation pressure and the TPMS 
low tire pressure warning threshold in order to allow for environmental 
effects, manufacturing variation, and other system variables, while 
avoiding nuisance warnings. Therefore, in order to specify a placard 
pressure of 35 psi, the TPMS activation threshold would need to be 
lowered to 25 to 28 psi.
    As discussed in its earlier petition for rulemaking on MAPs,\32\ 
the Alliance argued that the MAP values in Table 1 are likely to prove 
problematic for certain vehicle applications. The Alliance stated that 
it had previously submitted certain component and vehicle test data in 
support of its petition, including LT tire test data supplied by 
General Motors (data from endurance tests, low inflation pressure 
tests, laboratory and on-vehicle bead unseating tests).\33\ Based upon 
such data, the Alliance has concluded that there is not a demonstrated 
safety need for the specific MAP values for LT tires set forth in Table 
1. According to the Alliance, more stringent requirements, testing at 
higher tire deflection levels, are already set by paragraph S6.4, ``Low 
Inflation Pressure Performance,'' of FMVSS No. 139, New Pneumatic 
Radial Tires for Light Vehicles, so there is arguably not any need for 
such a requirement under FMVSS No. 138.
---------------------------------------------------------------------------

    \32\ Docket No. NHTSA-2000-8572-265 and 266.
    \33\ The petition also stated that additional data related to 
the MAP issue were supplied by the Alliance and GM at Docket No. 
NHTSA-2000-8572-268 and Docket No. NHTSA-2004-19054-95.
---------------------------------------------------------------------------

    Therefore, in its petition, the Alliance identified three 
recommended options for addressing the MAP issue: (1) Eliminate the MAP 
requirement for LT tires; (2) adopt the MAP values proposed by the 
Alliance, or (3) adopt 29 psi as the MAP for all LT tires (Load Range 
C, D, and E).
    In its petition, the RMA expressed an opposing viewpoint on the MAP 
issue, objecting to the decision in the final rule to lower the MAP for 
Load Range D and E tires to 35 psi. The RMA argued that a MAP of 35 psi 
for these tires will not ensure that consumers receive an adequate 
warning before the tires become significantly under-inflated or over-
inflated. The RMA recommended that the agency conduct further 
rulemaking related to MAPs, including issuance of an NPRM, so that the 
interested public has an opportunity to provide additional information 
and to fully participate in the resolution of this issue. (Michelin's 
petition made the same arguments on this issue as the RMA petition, and 
it incorporated the RMA's document by reference.)
    After careful consideration of the petitions addressing the MAP 
issue, we have decided to confirm and retain the MAP values for LT 
tires as presented in

[[Page 53090]]

Table 1. As noted in the final rule, the TRA Year Book includes load/
pressure relationships for Load Range D and E tires from 80 psi 
(maximum inflation pressure) down to 35 psi. This value provides a 
benchmark, indicating that a Load Range D or E tire could be safely 
operated at an inflation pressure as low as 35 psi. This approach is 
analogous to the approach we used in selecting the MAP values for P-
metric tires, although the various tire industry publications exhibited 
more consistent values for P-metric tires.
    The MAP values in Table 1 provide a floor value for activation of 
the TPMS for given classes of tires, and we do not believe that it is 
consistent with safety to eliminate the MAP for Load Range D and E 
tires. The MAPs play an important role in the TPMS's ability to provide 
a timely warning to the driver regarding low tire pressure. We believe 
that the minimum operating pressure recommended for Load Range D and E 
tires in the TRA Year Book is an adequate and safe value for the MAP. 
We are aware that a MAP of 35 psi effectively requires that the minimum 
vehicle placard pressure be 40 to 45 psi to ensure proper TPMS 
function. However, we expect that the MAP issue raised by the Alliance 
and GM is only likely to impact a small percentage of vehicles using LT 
tires (i.e., typically vehicles with a GVWR of over 8,500 pounds).\34\ 
Furthermore, our analysis of the available data has led us to conclude 
that the MAP values currently presented in Table 1 should not have a 
significant negative impact upon vehicle handling or the propensity for 
rollover, so we believe that the current MAP values provide a long-term 
resolution of this issue without the need for further rulemaking.\35\
---------------------------------------------------------------------------

    \34\ Docket No. NHTSA-2000-8572-265.
    \35\ DOT HS 809 701.
---------------------------------------------------------------------------

    With regard to the RMA and Michelin petitions, neither of them 
provided any data or rationale explaining why the agency should 
initiate new, separate rulemaking to address the MAP issue for Load 
Range D and E tires. These petitions merely provided a conclusory 
statement that MAP values of 35 psi will not ensure that consumers will 
be warned before the tires are dangerously overloaded or under-
inflated.

E. Owner's Manual Requirements

    Under S4.5, the owner's manual of each vehicle certified as 
complying with FMVSS No. 138 must provide an image of the Low Tire 
Pressure Telltale symbol (and an image of the TPMS Malfunction Telltale 
warning (``TPMS''), if a dedicated telltale is utilized for this 
function) with the following statement in English:

    Each tire, including the spare (if provided), should be checked 
monthly when cold and inflated to the inflation pressure recommended 
by the vehicle manufacturer on the vehicle placard or tire inflation 
pressure label. (If your vehicle has tires of a different size than 
the size indicated on the vehicle placard or tire inflation pressure 
label, you should determine the proper inflation pressure for those 
tires.)
    As an added safety feature, your vehicle has been equipped with 
a tire pressure monitoring system (TPMS) that illuminates a low tire 
pressure telltale when one or more of your tires is significantly 
under-inflated. Accordingly, when the low tire pressure telltale 
illuminates, you should stop and check your tires as soon as 
possible, and inflate them to the proper pressure. Driving on a 
significantly under-inflated tire causes the tire to overheat and 
can lead to tire failure. Under-inflation also reduces fuel 
efficiency and tire tread life, and may affect the vehicle's 
handling and stopping ability.
    Please note that the TPMS is not a substitute for proper tire 
maintenance, and it is the driver's responsibility to maintain 
correct tire pressure, even if under-inflation has not reached the 
level to trigger illumination of the TPMS low tire pressure 
telltale.
    [The following paragraph is required for all vehicles certified 
to the standard starting on September 1, 2007 and for vehicles 
voluntarily equipped with a compliant TPMS MIL before that time.] 
Your vehicle has also been equipped with a TPMS malfunction 
indicator to indicate when the system is not operating properly. 
[For vehicles with a dedicated MIL telltale, add the following 
statement: The TPMS malfunction indicator is provided by a separate 
telltale, which displays the symbol ``TPMS'' when illuminated.] [For 
vehicles with a combined low tire pressure/MIL telltale, add the 
following statement: The TPMS malfunction indicator is combined with 
the low tire pressure telltale. When the system detects a 
malfunction, the telltale will flash for approximately one minute 
and then remain continuously illuminated. This sequence will 
continue upon subsequent vehicle start-ups as long as the 
malfunction exists.] When the malfunction indicator is illuminated, 
the system may not be able to detect or signal low tire pressure as 
intended. TPMS malfunctions may occur for a variety of reasons, 
including the installation of replacement or alternate tires or 
wheels on the vehicle that prevent the TPMS from functioning 
properly. Always check the TPMS malfunction indicator after 
replacing one or more tires or wheels on your vehicle to ensure that 
the replacement or alternate tires and wheels allow the TPMS to 
continue to function properly.

    For vehicles that do not come with an owner's manual, the required 
information must be provided in writing to the first purchaser of the 
vehicle (S4.5(c)).
    As provided under S4.5(b), vehicle manufacturers may include 
information in the owner's manual about the time for the TPMS 
telltale(s) to extinguish once the low tire pressure condition or the 
malfunction is corrected. Vehicle manufacturers may also include 
information in the owner's manual about the significance of the low 
tire pressure warning telltale illumination, a description of 
corrective action to be undertaken, whether the TPMS functions with the 
vehicle's spare tire (if provided), and how to use a reset button (if 
one is provided).
    Petitioners recommended changes to the content of the owner's 
manual language, and they also requested additional lead time for 
implementing the standard's owner's manual provisions. These arguments 
are presented immediately below.
1. Lead Time
    The Alliance argued that because the owner's manual requirements of 
FMVSS No. 138 do not provide any additional lead time for those 
provisions, they significantly impact the ability of manufacturers to 
earn and apply carry-forward and carry-backward credits. The Alliance 
stated that the text for the required owner's manual language differs 
substantially from that incorporated in the June 2002 final rule (since 
vacated) or September 2004 NPRM, and its petition also stated that 
current owner's manuals of TPMS-equipped vehicles contain a statement 
consistent with the language provided in one or the other of those two 
notices.
    The Alliance stated that preparation of owner's manuals normally 
involves a one-to-two year process, something that the Alliance claims 
that NHTSA has recognized in other proceedings.\36\ Although at first 
blush these owner's manual changes may seem like a simple matter, the 
Alliance argued that the multiplicity of brands and models 
significantly increases the complexity of this task. Furthermore, the 
Alliance's petition stated that, overall, since the time of the June 5, 
2002 final rule, ``the different versions of the [required owner's 
manual] text differ only in detail, and not in substance or intent.'' 
As a result, the Alliance argued that

[[Page 53091]]

such differences do not justify hindering manufacturers' ability to 
introduce TPMSs in an expedited fashion. For the above reasons, the 
Alliance recommended delaying the effective date for all TPMS-related 
owner's manual requirements until September 1, 2006.
---------------------------------------------------------------------------

    \36\ The Alliance referenced NHTSA's final rule responding to 
petitions for reconsideration of the Tire Safety Information 
rulemaking (see 68 FR 33655 (June 5, 2003) (Docket No. NHTSA-2003-
15278-1)). In that rule, the agency decided to extend the final 
rule's lead time (of less than one year) for an additional year, in 
part because of the need for vehicle manufacturers to effect changes 
to owner's manuals. The notice stated, ``Additionally, for all car 
lines, manufacturers will be required to make extensive changes to 
their owner's manuals and these changes typically require a longer 
lead time than that provided by the final rule.'' 68 FR 33655, 33656 
(June 5, 2003).
---------------------------------------------------------------------------

    The AIAM's petition raised many of the same arguments regarding the 
need for lead time for the owner's manual requirements, both for 
vehicles that manufacturers intend to earn carry-forward credits, as 
well as for other vehicles. However, the AIAM's petition differed in 
that it asked NHTSA to delay the standard's compliance date for TPMS-
related owner's manual requirements until September 1, 2007. Because 
that is the date for mandatory compliance with the standard's 
malfunction detection requirements, the AIAM reasoned that such date 
would allow all required owner's manual language related to the TPMS to 
be incorporated at the same time.
    After careful consideration of these petitions, we have decided to 
delay the compliance date for the TPMS owner's manual requirement, 
thereby granting petitions' request for additional lead time to 
incorporate the required language into the vehicle owner's manual. We 
have decided to postpone compliance with the owner's manual requirement 
until September 1, 2006, and we are modifying S4.5(a) of the standard 
accordingly. (We note that the compliance date for incorporation of the 
required language related to the TPMS MIL is has not changed (i.e., 
September 1, 2007).) We believe that this request can be granted 
without negatively impacting vehicle safety. First, delay of the 
owner's manual requirements would not impact the functioning of the 
TPMS or the warnings that it provides. Furthermore, we expect that even 
before that date, TPMS-equipped vehicles would have some owner's manual 
statement presenting relevant information to the consumer. This change 
should facilitate vehicle manufacturers' ability to earn carry-forward 
and carry-backward credits for TPMSs that otherwise comply with FMVSS 
No. 138 since publication of the April 8, 2005 final rule.
    We specifically note that delay in the compliance date for the 
standard's owner's manual requirements does not impact vehicle 
manufacturers' responsibility to provide TPMSs complying with FMVSS No. 
138 on a schedule consistent with the phase-in commencing on October 5, 
2005, as set forth in the April 8, 2005 final rule.
    We are denying the AIAM's request to extend the vehicle owner's 
manual requirements until September 1, 2007. Based upon our analysis, 
we believe that a September 1, 2006 compliance date is practicable, so 
we do not see any reason to further delay presentation of a 
standardized message to consumers regarding the presence and function 
of TPMSs.
2. Content of Required Statement
    In its petition, ETRTO argued that the provisions in the April 8, 
2005 final rule dealing with the owner's manual language may be 
inadequate to warn consumers regarding potential TPMS shortcomings. 
Accordingly, ETRTO recommended that S4.5 of the standard be amended to: 
(1) Clearly explain the precautions that the consumer must take to 
ensure proper functioning of the TPMS for systems equipped with a 
manual reset feature (e.g., to prevent recalibration at an incorrect 
inflation level); (2) explicitly state that the TPMS may not alert the 
driver for a 20-minute period immediately after a malfunction occurs, 
until such time as the TPMS can detect the malfunction, and (3) 
require, rather than permit, vehicle manufacturers to provide the 
information specified under S4.5(b).
    SRI recommended amending S4.5(a) by supplementing the required 
statement in the vehicle owner's manual with the following additional 
language to make consumers aware that other anomalous situations may 
exist:

    When illuminated, the malfunction warning light indicates that 
the TPMS is not receiving a signal from the inflation pressure or 
wheel sensors. However, even if the malfunction warning light is not 
illuminated there can be conditions that can cause the system to be 
less sensitive to the tire pressure loss. It is the driver's 
responsibility to maintain correct tire pressure even if both TPMS 
and malfunction indicator lamps are not illuminated.

SRI argued that its recommended owner's manual language is necessary 
because it is not possible to anticipate all problems that would cause 
inaccuracies in a TPMS's functioning, some of which may not be capable 
of being detected by the TPMS malfunction indicator.
    After careful review, we have decided that no further modifications 
to the vehicle owner's manual requirements are required as a result of 
the ETRTO and SRI petitions. We believe that the language set forth in 
the April 8, 2005 final rule provides a clear message to the consumer 
regarding the presence and function of the TPMS installed in the 
vehicle, as well as its supporting role to the vehicle operator's 
ongoing responsibility for regular tire maintenance. We believe that 
the required owner's manual statement accomplishes its purpose, so it 
is not necessary to require the additional language recommended by 
ETRTO and SRI.
    Furthermore, we have decided to deny ETRTO's request to make 
mandatory the other TPMS-related topics addressed in S4.5(b). Again, 
because we believe that the required statement under S4.5(a) provides a 
clear and simple explanation about the TPMS to the consumer, we believe 
the optional topics listed in S4.5(b) may be beneficial, but are not 
necessarily critical. In addition, some of those topics may not apply 
to all vehicles, depending upon the type of TPMS technology installed.
3. Other Owner's Manual Issues
    The Alliance recommended moving the requirements currently 
contained in S4.5, Written Instructions, from 49 CFR part 571 (i.e., 
FMVSS No. 138) to 49 CFR part 575, Consumer Information, the locus of 
other owner's manual requirements involving specific language. 
According to the Alliance, other safety standards under part 571 with 
requirements for the owner's manual generally provide manufacturers 
discretion to include their own descriptions of certain required 
information or elements (e.g., FMVSS Nos. 108, 202, 205, 208, 210).
    The Alliance expressed concern that retention of the owner's manual 
requirement in part 571 could unnecessarily trigger the recall and 
remedy provisions under 49 U.S.C. 30118 and 30120. The Alliance argued 
that even a typographical error, no matter how minor or insignificant, 
would at the very least require the manufacturer to notify NHTSA that a 
noncompliance exists by filing a report under 49 CFR part 573, Defect 
and Noncompliance Reports, and to petition for a determination of 
inconsequentiality.
    Furthermore, the Alliance argued that movement of the TPMS-related 
owner's manual requirements to part 575 would not have any impact upon 
vehicle manufacturers' compliance, because even with such a change, 
manufacturers would still be subject to the penalty provisions of part 
578, Civil and Criminal Penalties, for violations of the part 575 
regulations. In addition, Alliance stated that there is already 
sufficient incentive for manufacturers to communicate effectively 
regarding safety issues, because vehicle manufacturers have a strong 
incentive to satisfy customers, to protect corporate reputation, and to 
avoid litigation.

[[Page 53092]]

    The Alliance argued that reassigning the TPMS-related owner's 
manual requirements to part 575 would alleviate any carry-forward 
credit concerns associated with text that does not precisely conform to 
that adopted in FMVSS No. 138. That is because under S7.4(a) of FMVSS 
No. 138 and subpart G of part 585 (TPMS Phase-in Reporting 
Requirements), a manufacturer must report compliance with all TPMS 
requirements, except for S4.4 which deals with the TPMS MIL, in order 
to earn carry-forward credits.
    The Alliance's petition also stated that the required owner's 
manual language presented in the agency's TPMS Laboratory Test 
Procedure (TP-138-00) does not match that set forth in S4.5(a). The 
Alliance asked the agency to reconcile this conflicting language.
    Upon consideration, we have decided to deny the Alliance request to 
move the requirement under S4.5(a) for the specific owner's manual 
statement to 49 CFR part 575. We believe that the required statement 
describing the TPMS and its role is a fundamental aspect of the 
standard, and accordingly, we believe that it should remain an integral 
part of FMVSS No. 138. Although it is true that errors in printing the 
owner's manual statement could trigger manufacturer responsibilities 
under the recall and remedy provisions of 49 U.S.C. 30118 and 30120, we 
believe that such instances would be rare and easily avoidable. Careful 
proofreading of pre-publication owner's manual statements should ensure 
that the standard's required language is faithfully executed, and in 
rare instances where typographical errors arise, those situations can 
be readily corrected through a petition for determination of 
inconsequential noncompliance.
    As to the Alliance's point regarding the discrepancy between the 
required owner's manual language in S4.5(a) of the standard and the 
TPMS Laboratory Test Procedure (TP-138-00), we have since corrected the 
latter document to remedy this inadvertent error (see http://nhtsa.gov/portal/site/nhtsa/menuitem.b166d5602714f9a73baf3210dba046a0/ 3210dba046a0/).

F. Test Procedures

    The test conditions for the TPMS may be found under S5 of the 
standard, and the corresponding test procedures may be found at S6 of 
the standard. Specific aspects of these test conditions and procedures 
are outlined below, along with focused issues raised in petitions for 
reconsideration.
    However, the petition submitted by ETRTO raised the issue of the 
adequacy of the test procedures generally, so that topic will be 
discussed and responded to as an initial matter. Specifically, ETRTO 
argued that the final rule's test procedures represent a step backward 
from the NPRM in terms of ensuring that drivers are warned promptly 
when a vehicle's tires are 25-percent under-inflated or reach the 
minimum activation pressure. ETRTO expressed concern that ``comparison 
of an under-inflation level checked while tyres are warm with a placard 
inflation level relative to cold tyres may be seriously misleading.'' 
The petitioner provided data intended to demonstrate the inconsistent 
results that may be presented, depending upon the tire and when it is 
tested under the test procedures of FMVSS No. 138. ETRTO stated that 
the final rule's arguments related to the vehicle cool-down period 
(discussed at section IV.C.4.d of the final rule) are not pertinent 
because they are not supported by experimental evidence. Furthermore, 
ETRTO argued that the final rule does not take into account measurement 
uncertainties and capabilities of TPMSs, and that measurement quality 
assurance principles have not been met. ETRTO also asserted that 
modifications are necessary because manometers at gas station air pumps 
are seriously inaccurate, something which could contribute to the above 
problems. For these reasons, ETRTO recommended reverting to the test 
procedures set forth in S6 of the NPRM, because it believes that those 
procedures are more likely to result in closer compliance with the 
standard's 25-percent under-inflation detection requirement.
    In response, we note that the test procedure for low tire pressure 
detection was modified in the final rule to eliminate the one-hour 
cool-down period after system calibration, because that provision 
required that the tires be cycled from cool to warm during the test. 
That would have introduced temperature and pressure uncertainties 
during the test procedure, and there would have been the possibility 
that tire pressure would rise to a level above the activation threshold 
for the low tire detection telltale. Elimination of the one-hour cool-
down period allows the low pressure test to be conducted with minimal 
temperature and pressure change.
    We believe that the arguments in the April 8, 2005 final rule 
related to the vehicle cool-down period (see section IV.C.6.d) are 
supported by the data in the ETRTO petition. That is, the tire pressure 
in the deflated tire remains below the TPMS telltale activation level 
while the vehicle is driven. With regard to the argument that the test 
procedure in the final rule allows the test pressure in the under-
inflated tire to be 30 percent or more below placard pressure, the 
compliance tests must be conducted at an under-inflation level of 25 
percent or more below placard or at the MAP. We believe that the test 
procedures, as amended in this final rule, will result in TPMS testing 
with an under-inflation level of 25-30 percent below placard for the 
test tire(s), which we also believe is sufficiently accurate when 
variations in ambient temperature, tire temperature, tire geometry, and 
test instrumentation are considered. The example offered by ETRTO in 
which tire pressure errors at service stations are calculated based on 
a pressure gauge with 90 percent accuracy, is not representative of the 
level of accuracy experienced in compliance or certification testing. 
For these reasons, we believe that the test procedures, as amended in 
response to the petitions, are appropriate.
1. Test Conditions
    The final rule included provisions under S5, Test Conditions, to 
specify the conditions under which the agency would conduct compliance 
testing under S6, Test Procedures. Specifically, S5 provided that 
during testing, the ambient temperature would be between 0[deg] C 
(32[deg] F) and 40[deg] C (104[deg] F) (see S5.1, as contained in the 
April 8, 2005 final rule). The road test surface will be any portion of 
the Southern Loop of the Treadwear Test Course defined in Appendix A 
and Figure 2 of 49 CFR 575.104, and the road surface will be dry during 
testing (see S5.2, as contained in the April 8, 2005 final rule).
    The vehicle will be tested at any weight between its lightly loaded 
vehicle weight and its gross vehicle weight rating (GVWR) without 
exceeding any of its gross axle weight ratings (see S5.3.1, as 
contained in the April 8, 2005 final rule). The vehicle's TPMS will be 
calibrated and tested at speeds between 50 km/h (31.1 mph) and 100 km/h 
(62.2 mph) (see S5.3.2, as contained in the April 8, 2005 final rule). 
The vehicle's rims may be positioned at any wheel position, consistent 
with any related instructions or limitations in the vehicle owner's 
manual (see S5.3.3, as contained in the April 8, 2005 final rule). The 
final rule also specifies that the vehicle's tires will be shaded from 
direct sun when the vehicle is parked (see S5.3.4, as contained in the 
April 8, 2005 final rule) and that driving time shall not accumulate 
during application of the service brake (see S5.3.5, as contained in 
the April 8, 2005 final rule).

[[Page 53093]]

    The RMA petitioned the agency to amend the test conditions in the 
TPMS standard to ensure that the system operates under all conditions 
that would represent the real-world driving environment. Although the 
RMA's petition did not set forth these recommended changes in detail, 
it did reference the same recommendations from the organization's 
earlier petition for rulemaking and its comments on the September 2004 
NPRM for TPMS. In those earlier submissions, the RMA argued that the 
temperature range for testing should be expanded to include ambient 
temperatures below freezing (32[deg] F) and above 104[deg] F. The RMA 
also advocated testing under slippery road conditions, increasing the 
range for the driving speed to include speeds over 100 kmh for low tire 
pressure detection, and testing during braking maneuvers.
    ETRTO made a similar argument in its petition, seeking changes to 
the standard's test condition to comport with the organization's 
suggestions presented at an earlier stage of the rulemaking. In its 
earlier submissions, ETRTO made comments similar to those provided by 
the RMA (discussed immediately above) on this issue, except that ETRTO 
also recommended testing at speeds below 31 mph. According to ETRTO, 
unless such modifications are made to better reflect actual driving 
environments, the standard will not maximize consumer safety, as 
required by the TREAD Act.
    The petition of VW/Audi argued that the Southern Loop of the Tread 
Wear Test Course may not represent a reasonable or practicable means of 
evaluating real-world TPMS usage, as would meet the objective of 
establishing a standard that would both enhance motor vehicle safety 
and also be practicable for compliance purposes. For this reason, VW/
Audi recommended that S6(d) and (f) of the standard's test procedures 
should be revised to permit up to 60 minutes of driving time for 
certification purposes. Specifically, VW/Audi recommended that S6(d), 
the system calibration/learning phase, should permit a cumulative total 
of 60 minutes of driving with a minimum of 10 minutes in at least three 
vehicle speed ranges (e.g., 50-70 kmh, 70-85 kmh, and 85-100 kmh (or 
some other sets of speed ranges with limits of <plus-minus>10 kmh)). 
VW/Audi also stated that the detection time in S6(f)(2) should be 
increased to a total cumulative time of 60 minutes, and that the drive 
time in S6(f)(3) should be the lesser of 60 minutes or the time at 
which the low tire pressure telltale illuminates.
    After considering the petitioners' comments regarding test 
conditions, we have decided that no further modifications to the test 
conditions in S5 are necessary. The agency's intention in developing 
the test procedure for TPMS-equipped vehicles was not to test the TPMS 
at every conceivable vehicle operating condition, but to instead 
evaluate the system at operating conditions that are typically 
encountered during normal driving. The RMA and ETRTO did not present 
any new data or arguments regarding the adequacy of the final rule's 
test conditions, nor did they specify any recommendations for test 
parameters that they believe would be more reflective of real world 
driving conditions.
    Consistent with the approach discussed above, the agency decided to 
specify the Southern Loop of the Tread Wear Test Course, a public 
roadway, for the compliance test, rather than using a test facility. We 
do not agree with the argument in the VW/Audi petition that the 
Southern Loop of the Tread Wear Test Course is not a reasonable or 
practicable means of evaluating real-world TPMS usage. We believe that 
a public roadway is highly representative of the real world conditions 
that may be encountered by drivers, and we further believe that, in 
light of the fact that this particular course has been used for several 
years for testing under our Uniform Tire Quality Grading Standards 
(UTQGS), there is not any reason to believe that the course would not 
similarly be suitable for TPMS testing.
    We are not adopting the suggestion of VW/Audi to specify that 
portions of the test be conducted in three <plus-minus>10 kmh subsets 
of the overall speed range specified in S5.3.2. The VW/Audi petition 
did not provide any data to demonstrate why these narrower speed range 
categories are necessary, and because vehicle operators are unlikely to 
observe such strictures during normal driving, we have decided to 
retain the final rule's speed range of 50-100 kmh (31.1-62.2 mph) 
without additional refinement. Furthermore, we do not believe that VW/
Audi's argument related to extending the time periods for TPMS 
calibration and low tire pressure detection is directly related to the 
standard's test conditions; accordingly, this issue is being addressed 
elsewhere in this notice.
    For these reasons, we continue to believe that the test conditions 
specified in the final rule will result in robust TPMSs that will 
function normally over a wide range of operating conditions. 
Accordingly, we do not believe that additional specifications related 
to temperature, weather, or speed would appreciably change the TPMS's 
performance. Furthermore, it is unlikely that design changes yielding 
greater safety benefits would result because vehicle manufacturers are 
aware of the temperature, weather, vehicle speed, and other conditions 
that their vehicles are exposed to and typically design to meet or 
exceed those conditions.
2. Vehicle Cool-Down Period
    Under S6, Test Procedures, the final rule states that the vehicle 
will be driven within five minutes after reducing the inflation 
pressure in the tire(s) as part of the low tire pressure detection 
phase (see S6(f)(1), as contained in the April 8, 2005 final rule), 
and, for vehicles in which the TPMS successfully detected low tire 
pressure, it also requires the vehicle's ignition to be turned off for 
five minutes, after which time the ignition locking system is 
reactivated to determine whether the system continues to detect the 
under-inflation condition (see S6(g), as contained in the April 8, 2005 
final rule). Under S6(h), the next sequential step in the test 
procedure, the vehicle is to be kept stationary for a period of up to 
one hour with the engine off, after which time the vehicle's tires are 
re-inflated and the TPMS should recognize that the low tire pressure 
situation has been resolved. The vehicle may be driven in order to 
allow the TPMS to check the tire pressure and to extinguish the low 
tire pressure telltale.
    In their petitions, ETRTO and SmarTire objected to the agency's 
decision in the April 8, 2005 final rule to eliminate the vehicle 
``cool down'' period in S6(e) and S6(f)(1), for the following reasons. 
With reference to the calibration/learning phase in S6(d), SmarTire 
argued that a 20-minute driving interval (especially at high speeds and 
high ambient temperatures) may increase tire pressure by 5-6 psi over 
placard pressure. SmarTire expressed concern that this pressure build-
up of 5-6 psi would still be present when the pressure in the tire(s) 
is reduced to the test pressure.
    SmarTire provided data indicating that as presently worded, the 
FMVSS No. 138 test procedure would permit a TPMS with only a 50-percent 
under-inflation detection capability, rather than the required 25-
percent under-inflation detection capability. SmarTire asserted that 
this situation could lead to irreparable structural damage to the tire, 
which could possibly lead to tire failure, so the petitioner 
recommended amending the final rule to restore the one-hour cool down 
period to the test procedure.
    ETRTO also provided tire pressure data obtained by driving a 
vehicle,

[[Page 53094]]

deflating the warm tires, and measuring tire pressure at various time 
intervals after tire deflation. The ETRTO data indicated that, under 
most deflation conditions, the warm tires that were deflated to 25 
percent below placard pressure minus 2 psi maintained a tire pressure 
of 30 percent or more below placard pressure.
    For the reasons that follow, we have decided against reinstating 
the one-hour cool-down period proposed in the NPRM. However, we are 
also sensitive to petitioners' arguments that the pressure during 
testing should be kept as close as possible to the standard's 25-
percent under-inflation activation threshold.
    Our understanding of the relevant positions on the cool-down period 
is as follows. Vehicle manufacturers expressed concern that if a 
vehicle is permitted to cool down for one hour after the calibration 
phase of testing, once the vehicle is driven, the tires will warm up, 
and tire pressure would be expected to rise by several psi. Thus, 
vehicle manufacturers are concerned that the tires may warm up to a 
point above the TPMS low tire activation threshold (i.e., less than 25 
percent below placard pressure), thereby causing the low tire pressure 
telltale to extinguish after illumination or not illuminate at all. 
Accordingly, the vehicle manufacturers favor both a short cool-down 
period (e.g., five minutes or less) and a larger temperature 
compensation adjustment (e.g., 2 psi).
    In contrast, tire manufacturers are concerned that there would be a 
30-percent or greater difference in pressure between: (a) A cold tire 
inflated to placard pressure and then heated up by driving and (b) a 
warm tire that has been deflated to 25 percent below placard pressure. 
Under real world driving conditions, this would increase the potential 
for tire damage and failure. Accordingly, tire manufacturers favor a 
longer cool-down period (e.g., one hour) and a smaller temperature 
compensation adjustment.
    In response to public comment from vehicle manufacturers at the 
NPRM stage, the agency reduced the cool-down period in S6(f)(1) from 
the NPRM's proposed one hour to the final rule's five minutes, in order 
to conduct the low pressure test without significant temperature 
variation. We agree with the vehicle manufacturers that elimination of 
the one-hour cool-down period will help maintain the under-inflated 
tire's pressure and allow it to remain below the TPMS activation 
threshold during testing. Although the pressure difference between the 
fully-inflated tires and the under-inflated tire(s) may be somewhat 
larger without the one-hour cool-down, the actual pressure of the 
under-inflated tire(s) would not be expected to be significantly above 
the standard's low tire pressure activation threshold. The SmarTire and 
ETRTO petitions did not provide any data to document the tire damage 
expected to occur as a result of the final rule's reduction in the time 
of the cool-down period, and they did not provide any alternative 
solution to the problem of tire pressure and temperature rising during 
vehicle operation. Accordingly, we have decided to retain the 
provisions in S6 related to vehicle cool-down as presented in the final 
rule without change.
3. 2-psi Adjustment (Temperature Correction)
    Under S6(e) of the final rule, any combination of one to four tires 
is deflated to 14 kPa (2 psi) below the inflation pressure at which the 
TPMS is required to illuminate the low tire pressure warning. This 
provision sets the stage for the test procedures' low pressure test 
(i.e., the system detection phase). This adjustment provides some 
margin in compliance testing to ensure that a warm tire does not cause 
a tire deflated by 25 percent below placard pressure to again rise 
slightly above the 25-percent TPMS warning threshold.
    The issue of the 2 psi adjustment in S6(e) of the test procedures 
was among the most frequently raised issues in the petitions for 
reconsideration (i.e., topic addressed by the Alliance, Michelin, the 
RMA, and SmarTire). The RMA stated that the final rule modified the 
test procedure to include a -14 kPa (-2 psi) adjustment in tire 
pressure during testing, rather than the -7 kPa (-1 psi) adjustment 
proposed in the NPRM, but it did not provide any independent testing 
data or other verification to support this change.
    To address this point, a number of RMA member companies conducted 
testing, and these data, provided with the RMA petition, suggested that 
this change to the test procedures could permit testing of the TPMS 
with tires under-inflated by 32 percent or more below placard pressure, 
rather than the required 25 percent. Furthermore, the RMA stated that 
its testing showed that by controlling the deflation rate, it would be 
possible to eliminate any increase in tire pressure that occurs after 
rapid tire deflation.
    The RMA offered the following recommended solution to this 
perceived problem, which it characterized as a minor modification of 
S6(e) of the standard's test procedures, but which it believes would 
produce consistent and objective results. Specifically, the RMA's 
petition called for a pressure re-check and reset after deflation 
through the following modified language (bracketed text is deleted 
text):

    Stop the vehicle and deflate any combination of one to four 
tires until the deflated tire(s) is (are) at [14 kPa (2 psi) below] 
the inflation pressure at which the tire pressure monitoring system 
is required to illuminate the low tire pressure warning telltale. 
After two minutes, re-check the tire pressure and adjust the 
pressure as necessary.

    Michelin reiterated the RMA's point that a -14 kPa (-2 psi) 
adjustment to the TPMS activation threshold could result in a TPMS 
being tested at 32 percent under-inflation, rather than the required 
level of 25 percent, and it incorporated the reasoning set forth in the 
RMA submission by reference. Michelin also provided an attachment to 
its petition intended to demonstrate the variability of the pressure 
increase for warm tires after deflation depending upon tire size and 
deflation technique.
    SmarTire also objected to the provision in the test procedures that 
sets the tire pressure at 14 kPa (2 psi) below the 25-percent-below-
placard level, because it argued that this approach could result in a 
TPMS being tested at 30-percent under-inflation. SmarTire stated that 
if a 14 kPa (2 psi) tolerance on test pressure setting is necessary for 
test consistency, then the agency should modify the standard to require 
the TPMS to illuminate the low tire pressure warning telltale at some 
point above the 25-percent under-inflation threshold, such that 25-
percent under-inflation remains the minimum requirement.
    The Alliance did not object to the level of the pressure adjustment 
provided in S6(e), but it did request further changes to S6 to account 
for the fact that environmental factors (e.g., ambient temperature, 
wind), road test surface temperature (i.e., heat transfer from road to 
tire), and sun load on the tires (during driving and when stationary) 
can impact tire temperature and tire pressure. According to the 
Alliance, unless the standard carefully controls for these factors, 
there is a significant risk that a vehicle will be mistakenly 
determined to be out of compliance.
    Therefore, the Alliance also recommended additional verification in 
order to provide an objective determination of noncompliance, which it 
believes may be accomplished by modifying S6(f) and (g) of the standard 
as follows:


[[Page 53095]]


    (f) If the low tire pressure telltale did not illuminate, stop 
the vehicle. Check the inflation pressure of the tire(s) deflated in 
S6(e).
    (i) If the pressure in the deflated tire(s) is below the 
inflation pressure at which the TPMS is required to illuminate the 
low tire pressure telltale, discontinue the test.
    (ii) If the pressure in the deflated tire(s) is above the 
inflation pressure at which the TPMS is required to illuminate the 
low tire pressure telltale, repeat procedure from S6(e).
    (g) If the low tire pressure telltale illuminated during the 
procedure in paragraph S6(f), turn the ignition locking system to 
the ``Off'' or ``Lock'' position. After a 5-minute period, turn the 
vehicle's ignition locking system to the ``On'' (``Run'') position. 
The telltale must illuminate and remain illuminated as long as the 
ignition locking system is in the ``On'' (``Run'') position. If the 
telltale does not illuminate or turns off during this procedure, 
check the inflation pressure of the tire(s) deflated in S6(e). If 
the pressure in the deflated tire(s) is below the inflation pressure 
at which the TPMS is required to illuminate the low tire pressure 
telltale, discontinue the test.

    After careful consideration of the petitioners' arguments related 
to the 2-psi pressure adjustment, we have decided to reduce that 
adjustment to 1 psi. However, we have decided that it is not necessary 
to incorporate the additional pressure checks recommended by the 
Alliance and the RMA. The following explains our rationale.
    In response to public comments submitted by NIRA Dynamics and VW/
Audi on the NPRM, we added the 2-psi pressure adjustment to the low 
tire pressure detection test in S6(f). However, given that the vehicle 
cool-down period has been significantly reduced and that the low tire 
pressure test is to be conducted without significant tire temperature 
variation, we are concerned that a 2-psi pressure adjustment may 
actually represent an under-inflation level closer to 30 percent, 
rather than the standard's stated activation threshold of 25-percent 
under-inflation. Assuming that a tire's inflation pressure typically 
rises 2-3 psi during normal vehicle operations, we believe that this is 
a valid concern. We believe that amending the standard to provide a 1-
psi adjustment under S6(f) would significantly reduce the amount of 
under-inflation deviation from the threshold level articulated in the 
standard.
    The Alliance recommended revising the test procedure in a manner 
that would eliminate the standard's current five-minute cool-down 
period because it believes that even a small delay could allow the 
tires to cool slightly, thereby resulting in a pressure decrease that 
could once again allow the pressure to increase above the detection 
threshold level, once the vehicle is driven again during the low 
pressure detection phase. According to the Alliance, the 2-psi 
adjustment helps ensure that any pressure increase as the vehicle is 
driven will not result in the pressure rising above the activation 
level. We have considered the Alliance's concerns, but we have decided 
that it is not necessary to eliminate the five-minute cool-down period 
and that it is possible to limit the pressure adjustment to 1 psi 
without triggering testing problems.
    Test data submitted by the RMA in August 2003 demonstrated that a 
tire's temperature and inflation pressure do not begin to decrease 
immediately following the end of the road wheel test (conducted under 
FMVSS No. 139), but instead, the tire maintains its operational 
temperature and pressure for a few minutes before beginning to slowly 
decrease to its initial test pressure.\37\
---------------------------------------------------------------------------

    \37\ Docket No. NHTSA-2003-15400-9.
---------------------------------------------------------------------------

    Data from studies of the relationship between tire pressure and 
time were submitted by the RMA \38\ and Michelin \39\ along with their 
petitions. These studies, which involved deflating tires at different 
rates and monitoring the pressure after deflation, indicated that tire 
pressure rose several psi above the pressure at which the deflation was 
ended when the deflation rate was rapid. However, for slower deflation 
rates, the pressure tended to remain very close to the value attained 
immediately after the deflation procedure was completed. Therefore, 
based upon the available information, we do not believe that it is 
necessary to eliminate the five-minute cool-down period or that it is 
critical to maintain a 2-psi pressure adjustment in the test procedure. 
We also do not believe that additional modifications are necessary to 
compensate for the ``environmental effects'' mentioned by the Alliance; 
the Alliance did not provide data demonstrating the extent of these 
alleged effects, and we believe that the standard accounts for such 
effects as promulgated.
---------------------------------------------------------------------------

    \38\ Docket No. NHTSA-2005-20586-21.
    \39\ Docket No. NHTSA-2005-20586-29.
---------------------------------------------------------------------------

    Instead, we believe that the Alliance's concerns can be 
accommodated by careful, deliberate administration of the test, as 
reflected in our more detailed Laboratory Test Procedure for TPMS (TP-
138-00). For example, in the Laboratory Test Procedure, we specify use 
of a pressure gauge with an accuracy of <plus-minus> 0.5 percent, which 
we believe would ensure that the tire pressure is close to the intended 
value when measured. Use of an accurate gauge is important so as to 
reduce the number of measurements needed to obtain an accurate reading. 
That is because each time a pressure measurement is taken from an 
inflated tire, there is a slight loss of inflation pressure, so fewer 
checks should result in fewer adjustments and less pressure loss. We do 
not believe that S6 requires amendment to incorporate additional 
pressure checks during testing to ensure that the pressure is at the 
correct value, because we believe that the existing procedures are 
adequate. We are also denying the RMA's recommendation to eliminate the 
pressure adjustment entirely, because we believe that such action would 
unnecessarily complicate our testing.
    Furthermore, we believe that deflating the tire to 1 psi below the 
25-percent under-inflation threshold, as opposed to 2 psi, would not 
change the stringency of the performance requirements specified in 
S4.2, but it would ensure that the pressure in the under-inflated 
tire(s) remains closely tied to the low tire pressure activation 
threshold. This adjustment was included to facilitate the vehicle test, 
not to relieve manufacturers' responsibility to provide a TPMS that can 
detect when a tire is 25-percent below placard pressure. Given the 
difficultly involved with allowing an extended tire cool-down period 
during the low pressure detection phase, we believe that amending the 
standard to provide a 1-psi pressure adjustment is a reasonable 
approach that should prevent actual under-inflation values that are 
significantly below the standard's 25-percent activation value.
4. Calibration Time
    Under the April 8, 2005 final rule, the standard's test procedures 
provide a cumulative time period of up to 20 minutes for TPMS 
calibration. During this system ``learning phase,'' the vehicle is 
driven for up to 15 minutes of cumulative time (not necessarily 
continuously) along any portion of the test course. Direction of travel 
on the test course is then reversed, and the vehicle is driven for an 
additional period of time, for a total cumulative time of 20 minutes. 
(See S6(d), as contained in the April 8, 2005 final rule.)
    As noted above, the petitions of NIRA Dynamics and VW/Audi asked 
that the standard be amended to provide a one-hour time period for TPMS 
calibration. The petitioners argued that effective calibration of their 
TPMSs requires up to one hour of time over a range of

[[Page 53096]]

speeds. In addition, the petitioners asserted that in light of the 
mechanism through which multiple-tire under-inflation occurs (i.e., 
through slow diffusion), calibration within 20 minutes is unnecessary.
    After careful consideration, we have decided to deny the 
petitioners' requests to increase calibration time from the current 20 
minutes to one hour. Even though the agency is committed to developing 
a standard that is as technology-neutral as possible, we believe that a 
60-minutes time period for TPMS calibration is too long. Were we to 
adopt a calibration time period consistent with the petitioners' 
recommendations, the average consumer might require several trips for 
the TPMS to be properly calibrated. While calibrating, the TPMS is 
unavailable to provide its important warning about low tire pressure. 
Furthermore, we note that TPMS calibration and under-inflation 
detection are sequential events, so those time periods must be added to 
properly reflect the amount of time that may elapse before the TPMS may 
provide a warning to the driver. This fact argues against extending 
calibration time in the manner the petitioners have suggested, 
particularly because situations exist where the low pressure condition 
may arise for reasons other than slow diffusion.
    Since there is no indication as to when the TPMS calibration 
process is complete, most consumers are likely to assume that 
calibration is complete shortly after the system reset button is 
activated, for systems that use a reset feature. We believe that such 
expectation brings about a false sense of security to consumers who may 
believe that once the reset button is activated, the system is again 
ready to detect low inflation pressure in any of the vehicle's tires. 
(Because the issue of calibration time is closely linked to the issue 
of low tire pressure warning activation, please see section IV.A of 
this notice for additional explanation regarding the need for the TPMS 
to provide its warnings promptly.)
    Depending upon how often there is a need to reset the system, there 
is the potential for the TPMS to be unavailable to provide a low tire 
pressure warning with some degree of frequency, which would add to our 
concern about extending the calibration time in S6(d). Furthermore, we 
note that Sumitomo Rubber Industries, a manufacturer of indirect TPMSs, 
currently produces a system that can calibrate within 20 minutes, 
thereby demonstrating the practicability of a 20-minute calibration 
requirement.\40\ We expect that with additional time and development, 
other systems could satisfy this requirement as well. For these 
reasons, we continue to believe that requiring TPMS calibration within 
20 minutes is appropriate.
---------------------------------------------------------------------------

    \40\ In a June 28, 2005 letter submitted to the docket, SRI 
suggested that additional calibration time would be beneficial in 
terms of system accuracy, although it is not absolutely necessary. 
(See Docket No. NHTSA-2005-20586-37).
---------------------------------------------------------------------------

G. TPMS Reprogrammability

    Under the final rule, vehicle manufacturers are permitted, but not 
required, to provide a TPMS reprogrammability feature. However, the 
final rule made clear that the agency will conduct compliance testing 
with the tires installed on the vehicle at the time of initial sale and 
will follow any manufacturer instructions in the owner's manual related 
to resetting the TPMS. (See 70 FR 18136, 18146 (April 8, 2005))
    According to SEMA, replacement tires for a vehicle may require 
higher inflation pressure than the vehicle's original equipment tires, 
and unless the TPMS is reprogrammed to reflect this new placard 
pressure, those replacement tires may become more than 25 percent 
under-inflated by the time the TPMS low tire pressure warning telltale 
illuminates. SEMA argued that this situation would both defeat the 
purpose of the rule and also give drivers a false sense of security, 
although SEMA acknowledged that it does not have specific information 
to demonstrate how significant this problem currently is or will be in 
the future. SEMA recommended that the standard be amended to require 
TPMS reprogrammability.
    We have decided to deny SEMA's request that we amend FMVSS No. 138 
to require TPMS reprogrammability, because there is no evidence to 
demonstrate an actual problem in this area. We believe that vehicle 
manufacturers installing TPMSs that may require reprogramming in 
certain situations are well aware of this issue and will provide this 
feature, as necessary. Thus, in the final rule, we expressly stated 
that TPMSs are permitted to be reprogrammable. Once again, although we 
are uncertain as to the exact details of system reprogrammability, we 
assume that it will be fairly easy for the service industry to 
reprogram TPMSs to accommodate different tires and rims.

H. Sharing of TPMS Servicing Information

    The April 8, 2005 final rule stated that the agency does not 
believe it necessary to mandate vehicle manufacturers to report repair 
and servicing information to the aftermarket sales industry and the 
service industry. As stated in the preamble to the final rule, NHTSA 
has not received any consumer complaints regarding the serviceability 
of existing TPMSs, and the agency expects that the marketplace will 
make sufficient information available to permit convenient sales, 
maintenance, and repair of such systems. (See 70 FR 18136, 18175 (April 
8, 2005))
    In its petition, SEMA reiterated the argument made in its comments 
on the NPRM that the agency should require vehicle manufacturers to 
share sufficient information to allow third-party servicing of TPMSs. 
SEMA stated that it has heard complaints that the service and repair 
industry and the aftermarket sales industry have been denied access to 
TPMS service information from both sensor manufacturers as well as 
vehicle manufacturers. However, SEMA did not provide any information to 
substantiate these anecdotal complaints, nor did it provide any facts 
to ascertain how large a problem there may be regarding access to 
service information. To resolve these concerns, SEMA recommended that 
the standard be amended to include a requirement that any TPMS 
servicing information must be made available to the vehicle owner, to 
the extent that such information is available to other parties.
    SEMA further argued that unless this recommendation and the other 
recommendations contained in its petition are followed, the rule may 
have a significant negative impact upon its small business members, 
because they may be unable to install their products if the TPMS MIL 
cannot be extinguished.
    We have decided to deny SEMA's request that we compel vehicle 
manufacturers to share TPMS servicing information with the service and 
repair industry. SEMA has not provided any evidence to demonstrate that 
vehicle manufacturers would not make necessary repair and servicing 
information available to the aftermarket sales industry and to the 
service industry, and its claims of a significant negative impact on 
its members are also speculative.
    As noted in the final rule, we have not received any consumer 
complaints regarding the serviceability of existing TPMSs. Vehicles 
currently include

[[Page 53097]]

many complex systems, and although dealer involvement may be 
necessitated in some cases, the marketplace has generally made 
available sufficient information to permit convenient maintenance and 
repair of such systems. We do not believe that TPMS technologies will 
prove any different in this regard.
    Furthermore, we are not requiring vehicle manufacturers to share 
TPMS servicing information with the vehicle owner. We believe that such 
a requirement would be unnecessary for the reasons discussed above and 
also because consumers are likely to find such highly technical 
information to be confusing and of little direct usefulness.

I. Phase-In Calculations

    Under S7, Phase-in Schedule, the final rule sets forth the 
requirements for vehicle manufacturer implementation of the TPMS 
standard. Specifically, under S7.1, for vehicles manufactured on or 
after October 5, 2005 and before September 1, 2006, the number of 
vehicles complying with the standard (other than the TPMS malfunction 
provisions of S4.4) must not be less than 20 percent of either: (a) The 
manufacturer's average annual production of vehicles manufactured on or 
after September 1, 2002 and before October 5, 2005, or (b) the 
manufacturer's production on or after October 5, 2005 and before 
September 1, 2006.
    Under S7.2, vehicles manufactured on or after September 1, 2006 and 
before September 1, 2007 are subject to a 70 percent phase-in of 
either: (a) The manufacturer's average annual production of vehicles 
manufactured on or after September 1, 2003 and before September 1, 
2006, or (b) the manufacturer's production on or after September 1, 
2006 and before September 1, 2007.
    As required by S7.3, all vehicles manufactured on or after 
September 1, 2007 must comply with all requirements of the standard, 
including the TPMS malfunction requirements of S4.4. However, S7.7 
provides an exception for vehicles manufactured by final-stage 
manufacturers and alterers, entities that are not subject to the phase-
in and for which the final rule provides an additional year for 
compliance (i.e., until September 1, 2008).
    The final rule provides carry-forward credits for vehicles that 
comply with the requirements of the standard and which are in excess of 
the compliance requirement for the phase-in reporting period in 
question (see S7.4(a), as contained in the April 8, 2005 final rule). 
In addition, the final rule provides carry-backward credits, through 
which a vehicle manufacturer is permitted to reduce its compliance 
responsibility during the first period of the phase-in, provided that 
it increases compliance by a corresponding number of vehicles during 
the second period of the phase-in (see S7.4(c), as contained in the 
April 8, 2005 final rule).
    The AIAM argued that the final rule is inconsistent regarding its 
articulation of the compliance requirement for the initial period of 
the phase-in (i.e., from October 5, 2005 to September 1, 2006). Its 
petition stated that the final rule's preamble calls for a 20 percent 
of a vehicle manufacturer's production to be equipped with TPMSs that 
are compliant with FMVSS No. 138 during that roughly eleven-month 
period. However, in the regulatory text, one of the options for 
calculating the number of vehicles that must comply during that period 
is based upon a full year of production (i.e., S7.1(a)). According to 
the AIAM, that provision of the final rule effectively requires a 
compliance rate of approximately 22 percent during the initial phase-in 
period (rather than 20 percent).
    To remedy this situation, the AIAM recommended revising S7.1(a) to 
read, ``The manufacturer's total production of vehicles manufactured on 
or after September 1, 2002, and before October 5, 2005, divided by 
3.414.'' Furthermore, the AIAM urged the agency to adopt a separate 
reporting requirement under 49 CFR 585.66(b) for the first phase-in 
period, which would require vehicle manufacturers to submit the 
following information: (1) The number of complying vehicles for the 
period from October 5, 2005, to August 31, 2006, and (2) total light 
vehicle production for that period, or total light vehicle production 
for the period from September 1, 2002, to October 5, 2005, depending 
upon the compliance option that is selected.
    After carefully considering AIAM's argument, we have decided to 
retain the phase-in requirement in S7 for the initial period of the 
phase-in without change. Under S7.1, a vehicle manufacturer has two 
options for calculating the number of FMVSS No. 138-compliant vehicles 
that must be produced during the initial period of the phase-in from 
October 5, 2005 to September 1, 2006. Consistent with the discussion in 
the preamble of the final rule, one of those options is 20 percent of 
the manufacturer's actual production during that period. Alternatively, 
the manufacturer may choose 20 percent of a three-year average as the 
basis for calculating the required number of complying vehicles. The 
manufacturer is free to choose whichever of these two options it 
considers to be the most advantageous.
    We do not believe that the difference between the shortened initial 
production period and the slightly lengthened three-year average will 
have a significant effect on the number of vehicles that will be 
required to comply with the standard in MY 2006. Given our 
understanding of vehicle manufacturers' production plans as reflected 
in their responses to the agency's September 9, 2003 Special Orders, we 
tentatively decided in the NPRM that 50 percent compliance during the 
first year of the phase-in would be reasonable; thus, the final rule's 
phase-in requirement of 20 percent for the initial period should be 
achievable under either method of calculation. Furthermore, carry-
backward credits are available under S7.4(c) of the standard to further 
ease implementation in the event the difference between the two methods 
of calculation under S7.1 somehow proves problematic.
    However, we are granting the AIAM's request that we modify 49 CFR 
585.66, Reporting Requirements, to differentiate the reports to be 
submitted to the agency for each of the two phase-in periods. As 
currently drafted, section 585.66(b)(1), Basis for Statement of 
Compliance, and section 585.66(b)(2), Production, require manufacturers 
to report values for the full production year,\41\ without mention of 
the period corresponding to the first period of the phase-in (i.e., 
from October 5, 2005 to September 1, 2006), which is the relevant total 
production value for calculation under S7.1(b) of FMVSS No. 138. 
Because the reporting of this information directly relates to 
determining compliance with the requirements of FMVSS No. 138, we have 
decided to revise 49 CFR 585.66(b)(1) and (2) to clearly differentiate 
between the two phase-in periods.
---------------------------------------------------------------------------

    \41\ Under 49 CFR 585.64, the term ``production year'' is 
defined as ``the 12-month period between September 1 of one year and 
August 31 of the following year, inclusive.''
---------------------------------------------------------------------------

V. Benefits and Costs

    Section VI of the April 8, 2005 final rule summarized the costs 
associated with the TPMS standard, as more fully described in the Final 
Regulatory Impact Analysis (FRIA) \42\ accompanying the final rule. The 
FRIA addresses the full range of anticipated costs related to TPMSs, 
including the cost of different TPMS technologies,

[[Page 53098]]

overall vehicle costs, maintenance costs, testing costs, and 
opportunity costs.
---------------------------------------------------------------------------

    \42\ Docket No. NHTSA-2005-20586-2.
---------------------------------------------------------------------------

    In summary, the FRIA estimated that the average incremental cost 
for all vehicles to meet the standard's requirements would range from 
$48.44-$69.89 per vehicle, depending upon the specific technology 
chosen for compliance. Since approximately 17 million vehicles are 
produced for sale in the U.S. each year, the total annual vehicle cost 
is expected to range from approximately $823-$1,188 million per year. 
The agency estimated that the net cost per vehicle would be $26.63-
$100.25 (assuming a one-percent TPMS malfunction rate for replacement 
tires) and that the total annual net cost would be approximately $453-
$1,704 million.
    The agency has determined that the technical amendments resulting 
from this final rule responding to petitions for reconsideration will 
not appreciably change the costs and benefits reported in the FRIA. 
Accordingly, the agency has decided that the estimates in that document 
remain valid and that additional analysis is not required.

VI. Rulemaking Analyses and Notices

A. Vehicle Safety Act

    Under 49 U.S.C. Chapter 301, Motor Vehicle Safety (49 U.S.C. 30101 
et seq.), the Secretary of Transportation is responsible for 
prescribing motor vehicle safety standards that are practicable, meet 
the need for motor vehicle safety, and are stated in objective 
terms.\43\ These motor vehicle safety standards set a minimum standard 
for motor vehicle or motor vehicle equipment performance.\44\ When 
prescribing such standards, the Secretary must consider all relevant, 
available motor vehicle safety information.\45\ The Secretary also must 
consider whether a proposed standard is reasonable, practicable, and 
appropriate for the type of motor vehicle or motor vehicle equipment 
for which it is prescribed and the extent to which the standard will 
further the statutory purpose of reducing traffic accidents and 
associated deaths.\46\ The responsibility for promulgation of Federal 
motor vehicle safety standards has been delegated to NHTSA.\47\
---------------------------------------------------------------------------

    \43\ 49 U.S.C. 30111(a).
    \44\ 49 U.S.C. 30102(a)(9).
    \45\ 49 U.S.C. 30111(b).
    \46\ Id.
    \47\ 49 U.S.C. 105 and 322; delegation of authority at 49 CFR 
1.50.
---------------------------------------------------------------------------

    As noted previously, section 13 of the TREAD Act mandated a 
regulation to require a tire pressure monitoring system in new 
vehicles. In satisfaction of this congressional directive, NHTSA 
established FMVSS No. 138, Tire Pressure Monitoring Systems, in a final 
rule published in the Federal Register on April 8, 2005. The agency 
received 17 petitions for reconsideration of the final rule, two of 
which were subsequently withdrawn. Most of these petitions raised 
issues involving technical modifications and correction. In this final 
rule responding to petitions for reconsideration, the agency carefully 
considered the statutory requirements of both the TREAD Act and 49 
U.S.C. Chapter 301.
    First, this final rule reflects the agency's careful consideration 
and analysis of all issues raised in the petitions for reconsideration. 
In responding to the issues raised in these petitions, the agency 
considered all relevant motor vehicle safety information. In preparing 
this document, the agency carefully evaluated available research, 
testing results, and other information related to various TPMS 
technologies. In sum, this document reflects our consideration of all 
relevant, available motor vehicle safety information.
    Second, to ensure that the TPMS requirements remain practicable, 
the agency evaluated the potential impacts of the petitions' requested 
actions in light of the cost, availability, and suitability of various 
TPMSs, consistent with our safety objectives and the requirements of 
the TREAD Act. As noted above, most of the changes resulting from this 
final rule involve relatively minor modifications to the April 8, 2005 
final rule for TPMS. In sum, we believe that this final rule responding 
to petitions for reconsideration is practicable and will maintain the 
benefits of the April 8, 2005 final rule, including prevention of 
deaths and injuries associated with significantly under-inflated tires, 
increased tread life, fuel economy savings, and savings associated with 
avoidance of property damage and travel delays (i.e., from crashes 
prevented by the TPMS).
    Third, the regulatory text following this preamble is stated in 
objective terms in order to specify precisely what performance is 
required and how performance will be tested to ensure compliance with 
the standard. Specifically, this final rule makes minor modifications 
to the performance requirements for operation of the TPMS, both in 
terms of detecting and providing warnings related to low tire pressure 
and system malfunction.
    The final rule also discusses test requirements for TPMS 
calibration, low tire pressure detection, and TPMS malfunction. This 
test involves driving the vehicle under a defined set of test 
conditions (e.g., ambient temperature, road test surface, test weight, 
vehicle speed, rim position, brake pedal application) on a designated 
road course in San Angelo, Texas. The test course has been used for 
several years by NHTSA and the tire industry for uniform tire quality 
grading testing. The standard's test procedures carefully delineate how 
testing will be conducted. The agency continues to believe that this 
test procedure is sufficiently objective and would not result in any 
uncertainty as to whether a given vehicle satisfies the requirements of 
the TPMS standard.
    Fourth, we believe that this final rule responding to petitions for 
reconsideration will meet the need for motor vehicle safety by making 
certain modifications that will enhance the ability of the TPMS 
standard to provide a warning to the driver when one or more tires 
become significantly under-inflated, thereby permitting the driver to 
take corrective action in a timely fashion and potentially averting 
crash-related injuries.
    Finally, we believe that this final rule responding to petitions 
for reconsideration is reasonable and appropriate for motor vehicles 
subject to the applicable requirements. As discussed elsewhere in this 
notice, the modifications to the standard resulting from this final 
rule will further the agency's efforts to address Congress' concern 
that significantly under-inflated tires could lead to tire failures 
resulting in fatalities and serious injuries. Under the TREAD Act, 
Congress mandated installation of a system in new vehicles to alert the 
driver when a tire is significantly under-inflated, and NHTSA has 
determined that TPMSs meeting the requirements of this final rule offer 
an effective countermeasure in these situations. Accordingly, we 
believe that this final rule is appropriate for covered vehicles that 
are or would become subject to these provisions of FMVSS No. 138 
because it furthers the agency's objective of preventing deaths and 
serious injuries associated with significantly under-inflated tires.

B. Executive Order 12866 and DOT Regulatory Policies and Procedures

    Executive Order 12866, ``Regulatory Planning and Review'' (58 FR 
51735, October 4, 1993), provides for making determinations whether a 
regulatory action is ``significant'' and therefore subject to OMB 
review and to the requirements of the Executive Order. The Order 
defines a ``significant regulatory action'' as one that is likely to 
result in a rule that may:

[[Page 53099]]

    (1) Have an annual effect on the economy of $100 million or more or 
adversely affect in a material way the economy, a sector of the 
economy, productivity, competition, jobs, the environment, public 
health or safety, or State, local, or Tribal governments or 
communities;
    (2) Create a serious inconsistency or otherwise interfere with an 
action taken or planned by another agency;
    (3) Materially alter the budgetary impact of entitlements, grants, 
user fees, or loan programs or the rights and obligations of recipients 
thereof; or
    (4) Raise novel legal or policy issues arising out of legal 
mandates, the President's priorities, or the principles set forth in 
the Executive Order.
    Although the April 8, 2005 final rule was determined to be 
economically significant, this final rule responding to petitions for 
reconsideration involves only relatively minor technical amendments to 
the FMVSS No. 138. Accordingly, it was determined that this final rule 
is not significant under either Executive Order 12866 or the Department 
of Transportation's Regulatory Policies and Procedures. The agency has 
estimated that the incremental costs associated with the minor 
modifications to the standard resulting from this final rule will not 
appreciably change the costs of compliance with FMVSS No. 138. 
Accordingly, the figures presented in the Final Regulatory Impact 
Analysis, docketed along with the April 8, 2005 final rule, remain 
apposite without modification.

C. 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 final rule under the 
Regulatory Flexibility Act. I certify that this final rule would not 
have a significant economic impact on a substantial number of small 
entities. The rationale for this certification is that the present 
final rule responding to petitions for reconsideration only makes 
technical modifications and corrections to the safety standard for 
TPMS. As discussed in detail in the April 8, 2005 final rule 
establishing FMVSS No. 138, we do not anticipate that the TPMS standard 
will have a significant economic impact on a substantial number of 
small entities, and nothing in this final rule would change either that 
assessment or its underlying reasoning.

D. Executive Order 13132 (Federalism)

    Executive Order 13132, ``Federalism'' (64 FR 43255, August 10, 
1999), requires NHTSA to develop an accountable process to ensure 
``meaningful and timely input by State and local officials in the 
development of regulatory policies that have federalism implications.'' 
``Policies that have federalism implications'' are defined in the 
Executive Order to include regulations that 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.'' Under 
Executive Order 13132, the agency may not issue a regulation with 
federalism implications, that imposes substantial direct compliance 
costs, and that is not required by statute, unless the Federal 
Government provides the funds necessary to pay the direct compliance 
costs incurred by State and local governments, the agency consults with 
State and local governments, or the agency consults with State and 
local officials early in the process of developing the proposed 
regulation. NHTSA also may not issue a regulation with federalism 
implications and that preempts a State law unless the agency consults 
with State and local officials early in the process of developing the 
regulation.
    Although statutorily mandated, this final rule responding to 
petitions for reconsideration of the TPMS standard was analyzed in 
accordance with the principles and criteria set forth in Executive 
Order 13132, and the agency determined that the rule would not have 
sufficient Federalism implications to warrant consultations with State 
and local officials or the preparation of a federalism summary impact 
statement. This final rule is not expected to have any substantial 
effects on the States, or on the current distribution of power and 
responsibilities among the various local officials.

E. Executive Order 12988 (Civil Justice Reform)

    Pursuant to Executive Order 12988, ``Civil Justice Reform'' (61 FR 
4729, February 7, 1996), the agency has considered whether this 
rulemaking would have any retroactive effect. This final rule does not 
have any retroactive effect. Under 49 U.S.C. 30103, whenever a Federal 
motor vehicle safety standard is in effect, a State may not adopt or 
maintain a safety standard applicable to the same aspect of performance 
which is not identical to the Federal standard, except to the extent 
that the State requirement imposes a higher level of performance and 
applies only to vehicles procured for the State's use. 49 U.S.C. 30161 
sets forth a procedure for judicial review of final rules establishing, 
amending, or revoking Federal motor vehicle safety standards. That 
section does not require submission of a petition for reconsideration 
or other administrative proceedings before parties may file a suit in 
court.

F. Executive Order 13045 (Protection of Children From Environmental 
Health and Safety Risks)

    Executive Order 13045, ``Protection of Children from Environmental 
Health and Safety Risks'' (62 FR 19855, April 23, 1997), applies to any 
rule that: (1) Is determined to be ``economically significant'' as 
defined under Executive Order 12866, and (2) concerns an environmental, 
health, or safety risk that the agency has reason to believe may have a 
disproportionate effect on children. If the regulatory action meets 
both criteria, the agency must evaluate the environmental health or 
safety effects of the planned rule on children, and explain why the 
planned regulation is preferable to other potentially effective and 
reasonably feasible alternatives considered by the agency.
    This final rule responding to petitions for reconsideration is not 
an economically significant regulatory action under Executive Order 
12866, and furthermore, the problems associated with under-inflated 
tires equally impact all persons riding in a vehicle, regardless of 
age. Consequently, this final rule does not involve decisions based 
upon health and safety risks that disproportionately affect

[[Page 53100]]

children, as would necessitate further analysis under Executive Order 
13045.

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. As part of 
the April 8, 2005 final rule, each of the estimated 21 affected vehicle 
manufacturers is required to provide one phase-in report for each of 
two years, beginning in the fall of 2006.
    Pursuant to the June 5, 2002 TPMS final rule, the OMB has approved 
the collection of information ``Phase-In Production Reporting 
Requirements for Tire Pressure Monitoring Systems,'' assigning it 
Control No. 2127-0631 (expires 6/30/06). NHTSA has been given OMB 
clearance to collect a total of 42 hours a year (2 hours per 
respondent) for the TPMS phase-in reporting. At an appropriate point, 
NHTSA may ask OMB for an extension of this clearance for an additional 
period of time.
    However, the present final rule responding to petitions for 
reconsideration does not contain any additional information collection 
requirements beyond those contained in the April 8, 2005 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 (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. The NTTAA directs us to provide 
Congress (through OMB) with explanations when we decide not to use 
available and applicable voluntary consensus standards. The NTTAA does 
not apply to symbols.
    There are no voluntary consensus standards related to TPMS 
available at this time. However, NHTSA will consider any such standards 
as they become available.

I. Unfunded Mandates Reform Act

    Section 202 of the Unfunded Mandates Reform Act of 1995 (UMRA) 
requires federal agencies to prepare a written assessment of the costs, 
benefits, and other effects of proposed or final rules that include a 
Federal mandate likely to result in the expenditure by State, local, or 
tribal governments, in the aggregate, or by the private sector, of more 
than $100 million annually (adjusted for inflation with base year of 
1995 (so currently about $112 million in 2001 dollars)). Before 
promulgating a NHTSA rule for which a written statement is needed, 
section 205 of the UMRA generally requires the agency to identify and 
consider a reasonable number of regulatory alternatives and adopt the 
least costly, most cost-effective, or least burdensome alternative that 
achieves the objectives of the rule. The provisions of section 205 do 
not apply when they are inconsistent with applicable law. Moreover, 
section 205 allows the agency to adopt an alternative other than the 
least costly, most cost-effective, or least burdensome alternative if 
the agency publishes with the final rule an explanation of why that 
alternative was not adopted.
    As discussed in that notice, the April 8, 2005 final rule 
establishing FMVSS No. 138 is not expected to result in the expenditure 
by State, local, or tribal governments, in the aggregate, of more than 
$112 million annually, but it is expected to result in an expenditure 
of that magnitude by vehicle manufacturers and/or their suppliers. In 
that final rule, NHTSA adopted a performance requirement for a system 
with a four-tire, 25-percent under-inflation detection capability; we 
believe that this approach is consistent with safety and the mandate in 
the TREAD Act, and it should provide a number of technological choices, 
thereby offering broad flexibility to minimize costs of compliance with 
the standard.
    In contrast, the present final rule responding to petitions for 
reconsideration only makes technical modifications and corrections to 
the standard. Therefore, we do not believe that this final rule will 
appreciably change the costs of compliance with FMVSS No. 138. 
Therefore, the agency has not prepared an economic assessment pursuant 
to the Unfunded Mandates Reform Act.

J. 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.

K. Regulatory Identifier Number (RIN)

    The Department of Transportation assigns a regulation identifier 
number (RIN) to each regulatory action listed in the Unified Agenda of 
Federal Regulations. The Regulatory Information Service Center 
publishes the Unified Agenda in April and October of each year. You may 
use the RIN contained in the heading at the beginning of this document 
to find this action in the Unified Agenda.

L. 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://dms.dot.gov.

List of Subjects in 49 CFR Parts 571 and 585

    Imports, Motor vehicle safety, Reporting and recordkeeping 
requirements, Tires.

0
In consideration of the foregoing, NHTSA is amending 49 CFR parts 571 
and 585 as follows:

PART 571--FEDERAL MOTOR VEHICLE SAFETY STANDARDS

0
1. The authority citation for part 571 of Title 49 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. Section 571.138 is amended by revising paragraphs S4.3.1(b), 
S4.4(b)(2) and (3), S4.4(c)(2), S4.5(a), S6(e), and S6(k) to read as 
follows:


Sec.  571.138  Standard No. 138; Tire pressure monitoring systems.

* * * * *
    S4.3 Low tire pressure warning telltale.
    S4.3.1 * * *
* * * * *
    (b) Is identified by one of the symbols shown for the ``Low Tire 
Pressure'' Telltale in Table 1 of Standard No. 101 (49 CFR 571.101); 
and
* * * * *
    S4.4 TPMS malfunction.
* * * * *
    (b) Dedicated TPMS malfunction telltale. * * *
* * * * *
    (2) Is identified by the word ``TPMS'' as described under the 
``Tire Pressure

[[Page 53101]]

Monitoring System Malfunction'' Telltale in Table 1 of Standard No. 101 
(49 CFR 571.101);
    (3) Continues to illuminate the TPMS malfunction telltale under the 
conditions specified in S4.4(a) for as long as the malfunction exists, 
whenever the ignition locking system is in the ``On'' (``Run'') 
position; and
* * * * *
    (c) Combination low tire pressure/TPMS malfunction telltale * * *
* * * * *
    (2) When the ignition locking system is activated to the ``On'' 
(``Run'') position, flashes for a period of at least 60 seconds but no 
longer than 90 seconds upon detection of any condition(s) specified in 
S4.4(a). After this period of prescribed flashing, the telltale must 
remain continuously illuminated as long as a malfunction exists and the 
ignition locking system is in the ``On'' (``Run'') position. This 
flashing and illumination sequence must be repeated each time the 
ignition locking system is placed in the ``On'' (``Run'') position 
until the situation(s) causing the malfunction(s) has (have) been 
corrected.
    S4.5 Written instructions.
    (a) Beginning on September 1, 2006, the owner's manual in each 
vehicle certified as complying with S4 must provide an image of the Low 
Tire Pressure Telltale symbol (and an image of the TPMS Malfunction 
Telltale warning (``TPMS''), if a dedicated telltale is utilized for 
this function) with the following statement in English: * * *
* * * * *
    S6 Test procedures.
* * * * *
    (e) Stop the vehicle and deflate any combination of one to four 
tires until the deflated tire(s) is (are) at 7 kPa (1 psi) below the 
inflation pressure at which the tire pressure monitoring system is 
required to illuminate the low tire pressure warning telltale.
* * * * *
    (k) Simulate one or more TPMS malfunction(s) by disconnecting the 
power source to any TPMS component, disconnecting any electrical 
connection between TPMS components, or installing a tire or wheel on 
the vehicle that is incompatible with the TPMS. When simulating a TPMS 
malfunction, the electrical connections for the telltale lamps are not 
to be disconnected.
* * * * *

PART 585--PHASE-IN REPORTING REQUIREMENTS

0
3. The authority citation for Part 585 of Title 49 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
4. Part 585 is amended by revising 585.66(b)(1) and (2) of Subpart G as 
follows:

Subpart G--Tire Pressure Monitoring System Phase-in Reporting 
Requirements

* * * * *


Sec.  585.66  Reporting requirements.

* * * * *
    (b) Report content. (1) Basis for statement of compliance. Each 
manufacturer must provide the number of passenger cars, multipurpose 
passenger vehicles, trucks, and buses with a gross vehicle weight 
rating of 4,536 kilograms (10,000 pounds) or less, except those 
vehicles with dual wheels on an axle, manufactured for sale in the 
United States for each reporting period as follows:
    (i) Period from October 5, 2005 to August 31, 2006. The number 
shall be either the manufacturer's average annual production of 
vehicles manufactured on or after September 1, 2002, and before October 
5, 2005, or, at the manufacturer's option, it shall be the 
manufacturer's production on or after October 5, 2005 and before 
September 1, 2006. A new manufacturer that has not previously 
manufactured these vehicles for sale in the United States must report 
the number of such vehicles manufactured during the production period 
on or after October 5, 2005 and before September 1, 2006.
    (ii) Period from September 1, 2006 to August 31, 2007. The number 
shall be either the manufacturer's average annual production of 
vehicles manufactured on or after September 1, 2003, and before 
September 1, 2006, or, at the manufacturer's option, it shall be the 
manufacturer's production on or after September 1, 2006 and before 
September 1, 2007. A new manufacturer that has not previously 
manufactured these vehicles for sale in the United States must report 
the number of such vehicles manufactured during the production period 
on or after September 1, 2006 and before September 1, 2007.
    (2) Production. Each manufacturer must report for the production 
period for which the report is filed: the total number of passenger 
cars, multipurpose passenger vehicles, trucks, and buses with a gross 
vehicle weight rating of 4,536 kilograms (10,000 pounds) or less that 
meet Standard No. 138 (49 CFR 571.138).
* * * * *

    Issued: August 31, 2005.
Jeffrey W. Runge,
Administrator.
[FR Doc. 05-17661 Filed 9-1-05; 10:32 am]
BILLING CODE 4910-59-P