[Federal Register Volume 67, Number 108 (Wednesday, June 5, 2002)]
[Rules and Regulations]
[Pages 38704-38749]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-13915]



[[Page 38703]]

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Part II





Department of Transportation





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National Highway and Traffic Safety Administration



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49 CFR Parts 571 and 590



Federal Motor Vehicle Safety Standards; Tire Pressure Monitoring 
Systems; Controls and Displays; Final Rule

  Federal Register / Vol. 67, No. 108 / Wednesday, June 5, 2002 / Rules 
and Regulations  

[[Page 38704]]


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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Parts 571 and 590

[Docket No. NHTSA 2000-8572]
RIN 2127-AI33


Federal Motor Vehicle Safety Standards; Tire Pressure Monitoring 
Systems; Controls and Displays

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

ACTION: Final rule.

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SUMMARY: In response to a mandate in the Transportation Recall 
Enhancement, Accountability, and Documentation (TREAD) Act of 2000, 
this agency is issuing a two-part final rule.
    The first part is contained in this document. It establishes a new 
Federal Motor Vehicle Safety Standard that requires the installation of 
tire pressure monitoring systems (TPMSs) that warn the driver when a 
tire is significantly under-inflated. The standard applies to passenger 
cars, trucks, multipurpose passenger vehicles, and buses with a gross 
vehicle weight rating of 10,000 pounds or less, except those vehicles 
with dual wheels on an axle.
    This document establishes two compliance options for the short-
term, for the period between November 1, 2003, and October 31, 2006. 
Under the first compliance option, a vehicle's TPMS must warn the 
driver when the pressure in any single tire or in each tire in any 
combination of tires, up to a total of four tires, has fallen to 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. Under the 
second compliance option, a vehicle's TPMS must warn the driver when 
the pressure in any single tire has fallen to 30 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. Compliance with the options would be 
phased in during that period by increasing percentages of production.
    The second part of this final rule will be issued by March 1, 2005, 
and will establish performance requirements for the long-term, i.e., 
for the period beginning on November 1, 2006. In the meantime, the 
agency will leave the rulemaking docket open for the submission of new 
data and analyses concerning the performance of TPMSs. The agency also 
will conduct a study comparing the tire pressures of vehicles without 
any TPMS to the pressures of vehicles with TPMSs, especially TPMSs that 
do not comply with the four-tire, 25 percent compliance option.
    Based on the record now before the agency, NHTSA tentatively 
believes that the four-tire, 25 percent option would best meet the 
mandate in the TREAD Act. However, it is possible that the agency may 
obtain or receive new information that is sufficient to justify a 
continuation of the options established by this first part of this 
rule, or the adoption of some other alternative.

DATES: This final rule is effective August 5, 2002. Under the rule, 
vehicles will be required to comply with the requirements of the 
standard according to a phase-in beginning on November 1, 2003. If you 
wish to submit a petition for reconsideration of this rule, your 
petition must be received by July 22, 2002.

ADDRESSES: Petitions for reconsideration should refer to the docket 
number and be submitted to: Administrator, Room 5220, National Highway 
Traffic Safety Administration, 400 Seventh Street, SW, Washington, DC 
20590.

FOR FURTHER INFORMATION CONTACT: For technical and other non-legal 
issues, you may call Mr. George Soodoo or Mr. Joseph Scott, Office of 
Crash Avoidance Standards (Telephone: 202-366-2720) (Fax: 202-366-
4329).
    For legal issues, you may call Mr. Dion Casey, 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.
    You may call Docket Management at 202-366-9324. You may visit the 
Docket on the plaza level at 400 Seventh Street, SW, Washington, DC, 
from 10:00 a.m. to 5:00 p.m., Monday through Friday.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Executive Summary
    A. Highlights of the Notice of Proposed Rulemaking
    B. Highlights of the Preliminary Determination About the Final 
Rule
    C. OMB Return Letter
    D. Highlights of the Final Rule
    1. Part One--Phase-in (November 2003 through October 2006)
    2. Part Two--November 2006 and Thereafter
    E. Summary Comparison of the Preliminary Determination and the 
Final Rule
II. Background
    A. The Transportation Recall Enhancement, Accountability, and 
Documentation Act
    B. Previous Rulemaking on Tire Pressure Monitoring Systems
    C. Summary of the Notice of Proposed Rulemaking
    D. Summary of Public Comments on Notice
    1. Vehicles Covered
    2. Phase-In Options and Long-Term Requirements
    a. Definition of ``Significantly Under-Inflated''
    b. Number of Tires Monitored
    3. Lead Time
    4. Reliability
    5. Costs and Benefits Estimates
    E. Submission of Draft Final Rule to OMB
    F. OMB Return Letter
    G. Public Comments on OMB's Return Letter
    H. Congressional Hearing
III. Safety Problem
    A. Infrequent Driver Monitoring of Tire Pressure
    B. Loss of Tire Pressure Due to Natural and Other Causes
    C. Percentage of Motor Vehicles with Under-Inflated Tires
    D. Consequences of Under-Inflation of Tires
    1. Reduced Vehicle Safety--Tire Failures and Increases in 
Stopping Distance
    2. Reduced Tread Life
    3. Reduced Fuel Economy
IV. Tire Pressure Monitoring Systems
    A. Indirect TPMSs
    B. Direct TPMSs
    C. Hybrid TPMSs
V. Summary of Preliminary Determination About the Final Rule
    A. Alternative Long-Term Requirements Analyzed in Making 
Preliminary Determination
    B. Phase-In and Long-Term Requirements
VI. Response to Issues Raised in OMB Return Letter About Preliminary 
Determination
    A. Criteria for Selecting the Long-Term Requirement
    1. Tire Safety and Overall Vehicle Safety
    2. Statutory Mandate
    B. Relative Ability of Direct and Current Indirect TPMSs to 
Detect Under-Inflation
    C. Analysis of a Fourth Alternative Long-Term Requirement: One-
Tire, 30 Percent Under-Inflation Detection
    D. Impact of One-Tire, 30 Percent Alternative on Installation 
Rate of ABS
    E. Overall Safety Effects of ABS
    F. Technical Foundation for NHTSA's Safety Benefit Analyses
VII. The Final Rule
    A. Decision to Issue Two-Part Final Rule
    B. Part One of the Final Rule--November 2003 through October 
2006
    1. Summary
    2. Congressional Intent
    3. Vehicles Covered
    4. Phase-In Options and Requirements
    a. Alternatives Considered
    i. Threshold Level of Under-Inflation
    ii. Number of Tires Monitored
    b. Option One: Four Tires, 25 Percent Under-Inflation
    c. Option Two: One Tire, 30 Percent Under-Inflation

[[Page 38705]]

    d. Special Written Instructions for Option Two TPMSs
    5. Other Requirements
    a. Time Frame for Telltale Illumination
    b. Duration of Warning
    c. Temporary Disablement
    d. System Calibration
    e. Replacement Tires
    f. Monitoring of Spare Tire
    g. Temperature Compensation
    h. Low Tire Pressure Warning Telltale
    i. Color
    ii. Symbol
    iii. Self-Check
    i. General Written Instructions for All TPMSs
    j. Test Conditions
    k. Test Procedures
    6. Lead Time
    C. Study of Effects of TPMSs That Do Not Meet a Four-Tire, 25 
Percent Under-Inflation Requirement
    1. Effect on Tire Pressure
    2. Effect on Number of Significantly Under-Inflated Tires
    D. Part Two of the Final Rule--November 2006 and Thereafter
VIII. Benefits
    A. Tire Safety Benefits
    1. Skidding/Loss of Control
    2. Stopping Distance
    3. Flat Tires and Blowouts
    4. Unquantified Benefits
    B. Non-Tire Safety Benefits
    C. Total Quantified Safety Benefits
    D. Economic Benefits
    1. Fuel Economy
    2. Tread Life
IX. Costs
    A. Indirect TPMSs
    B. Direct TPMSs
    C. Hybrid TPMSs
    D. Vehicle Cost
    E. Maintenance Costs
    F. Testing Costs
    G. Unquantified Costs
    H. ABS Costs
    I. Net Costs and Costs Per Equivalent Life Saved
X. Rulemaking Analyses and Notices

I. Executive Summary

A. Highlights of the Notice of Proposed Rulemaking

    NHTSA initiated this rulemaking with the publication of a Notice of 
Proposed Rulemaking (NPRM)(66 FR 38982, Docket No. NHTSA-2000-8572) on 
July 26, 2001. The NPRM proposed to require passenger cars, light 
trucks, multipurpose passenger vehicles, and buses with a gross vehicle 
weight rating of 10,000 pounds or less, except those vehicles with dual 
wheels on an axle, to be equipped with a tire pressure monitoring 
system (TPMS).
    The agency sought comment on two alternative sets of performance 
requirements for TPMSs and proposed adopting one of them in the final 
rule. The first alternative would have required that the driver be 
warned when the pressure in any single tire or in each tire in any 
combination of tires, up to a total of four tires, had fallen to 20 
percent or more below the vehicle manufacturer's recommended cold 
inflation pressure for the vehicle's tires (the placard pressure), or a 
minimum level of pressure specified in the standard, whichever was 
higher. (This alternative is referred to below as the four-tire, 20 
percent alternative.) The second alternative would have required that 
the driver be warned when the pressure in any single tire or in each 
tire in any combination of tires, up to a total of three tires, had 
fallen to 25 percent or more below the placard pressure, or a minimum 
level of pressure specified in the standard, whichever was higher. 
(This alternative is referred to below as the three-tire, 25 percent 
alternative.) The minimum levels of pressure were the same in both 
proposed alternatives. The adoption of four-tire, 20 percent 
alternative would have required that drivers be warned of under-
inflation sooner and in a greater array of circumstances. It would also 
have narrowed the range of technologies that manufacturers could use to 
comply with the new standard.
    There are two types of TPMSs currently available, direct TPMSs and 
indirect TPMSs. Direct TPMSs have a tire pressure sensor in each tire. 
The sensors transmit pressure information to a receiver. Indirect TPMSs 
do not have tire pressure sensors. Current indirect TPMSs rely on the 
wheel speed sensors in an anti-lock braking system (ABS) to detect and 
compare differences in the rotational speed of a vehicle's wheels. 
Those differences correlate to differences in tire pressure because 
decreases in tire pressure cause decreases in tire diameter that, in 
turn, cause increases in wheel speed.
    To meet the four-tire, 20 percent alternative, vehicle 
manufacturers likely would have had to use direct TPMSs because even 
improved indirect systems would not likely be able to detect loss of 
pressure until pressure has fallen 25 percent and could not detect all 
combinations of significantly under-inflated tires. To meet the three-
tire, 25 percent alternative, vehicle manufacturers would have been 
able to install either direct TPMSs or improved indirect TPMSs, but not 
current indirect TPMSs.

B. Highlights of the Preliminary Determination About the Final Rule

    NHTSA preliminarily determined to issue a final rule that would 
have specified a four-year phase-in schedule\1\ and allowed compliance 
with either of two options during the phase-in, i.e., between November 
1, 2003 and October 31, 2006. Under the first option, a vehicle's TPMS 
would have had to warn the driver when the pressure in one or more of 
the vehicle's tires, up to a total of four tires, was 25 percent or 
more below the placard pressure, or a minimum level of pressure 
specified in the standard, whichever pressure was higher. (This option 
is referred to below as the four-tire, 25 percent option.) Under the 
second option, a vehicle's TPMS would have had to warn the driver when 
the pressure in any one of the vehicle's tires was 30 percent or more 
below the placard pressure, or a minimum level of pressure specified in 
the standard, whichever pressure was higher. (This option is referred 
to below as the one-tire, 30 percent option.) The minimum levels of 
pressure specified in the standard were the same for both compliance 
options.
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    \1\ The phase-in schedule was as follows: 10 percent of a 
manufacturer's affected vehicles would have had to comply with 
either compliance option in the first year; 35 percent in the second 
year; and 65 percent in the third year. In the fourth year, 100 
percent of a manufacturer's affected vehicles would have had to 
comply with the long-term requirements, i.e., the four-tire, 25 
percent compliance option.
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    After the phase-in, i.e., after October 31, 2006, the second option 
would have been terminated, and the provisions of the first option 
would have become mandatory for all new vehicles. Thus, all vehicles 
would have been required to meet a four-tire, 25 percent requirement.

C. OMB Return Letter

    After reviewing the draft final rule, OMB returned it to NHTSA for 
reconsideration, with a letter explaining its reasons for doing so, on 
February 12, 2002. In the letter, OMB stated its belief that the draft 
final rule and accompanying regulatory impact analysis did not 
adequately demonstrate that the agency had selected the best available 
method of improving overall vehicle safety.

D. Highlights of the Final Rule

    In response to the OMB return letter, the agency has decided to 
divide the final rule into two parts. The first part is contained in 
this document, which establishes requirements for vehicles manufactured 
during the first three years, i.e., between November 1, 2003, and 
October 31, 2006, and phases them in by increasing percentages of 
production. The second part will establish requirements for vehicles 
manufactured on or after November 1, 2006.
    The agency has divided the final rule into two parts because it has 
decided to

[[Page 38706]]

defer its decision as to which long-term performance requirements for 
TPMS would best satisfy the mandate of the TREAD Act. This deferral 
will allow the agency's consideration of additional data on the effect 
and performance of TPMSs. From the beginning, the agency has sought to 
comply with the mandate and safety goals of the TREAD Act in a way that 
encourages innovation and allows a range of technologies to the extent 
consistent with providing drivers with sufficient warning of low tire 
pressure under a broad variety of the reasonably foreseeable 
circumstances in which tires become under-inflated.
1. Part One--Phase-in (November 2003 through October 2006)
    NHTSA has decided to require vehicle manufacturers to equip their 
light vehicles (i.e., those with a gross vehicle weight rating (GVWR) 
of 10,000 lbs. or less) with TPMSs and to give them the option for 
complying with either of two sets of performance requirements during 
the period covered by the first part of the final rule, i.e., from 
November 1, 2003 to October 31, 2006. The options are the same as those 
in the preliminary determination about the final rule.
    Under the first set or compliance option, the vehicle's TPMS will 
be required to warn the driver when the pressure in any single tire or 
in each tire in any combination of 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. Under the 
second compliance option, the vehicle's TPMS will be required to warn 
the driver when the pressure in any single tire is 30 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.\2\
    The two compliance options are outgrowths of the alternative sets 
of requirements proposed in the NPRM. In response to comments 
confirming that current indirect TPMSs cannot meet the proposed three-
tire, 25 percent under-inflation requirements, and in order to allow 
those systems to be used during the phase-in, the agency is adopting 
requirements for detection of one-tire, 30 percent under-inflation as 
the first option. For the second option, the agency is adopting 
requirements for detection of 4-tire, 25 percent under-inflation. 
Adopting those requirements, instead of the proposed requirements for 
four-tire, 20 percent under-inflation, will permit manufacturers to use 
either direct TPMSs or hybrid TPMSs, i.e., TPMSs that combine direct 
and indirect TPMS technologies. One TPMS supplier indicated the 
potential for developing and producing hybrid systems, although it also 
indicated that it did not currently have plans for doing so. The agency 
believes that the difference in benefits between TPMSs meeting four-
tire, 20 percent requirements and TPMSs meeting four-tire, 25 percent 
requirements should not be substantial.
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    \2\ The minimum levels of pressure are the same for both 
compliance options.
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    To facilitate compliance with the options, the rule phases them in 
by increasing percentages of production. Ten percent of a vehicle 
manufacturer's light vehicles will be required to comply with either 
compliance option during the first year (November 1, 2003 to October 
31, 2004), 35 percent during the second year (November 1, 2004 to 
October 31, 2005), and 65 percent during the third year (November 1, 
2005 to October 31, 2006). These percentages are the same as those in 
the preliminary determination about the final rule. The agency is 
allowing carry-forward credits for vehicles that are manufactured 
during the phase-in and are equipped with TPMSs that comply with the 
four-tire, 25 percent option. It is not allowing credits for TPMSs 
complying with the other option for the same reason that the agency is 
requiring manufacturers to provide consumers with information about the 
performance limitations of those systems.
    The combination of the two compliance options and the phase-in will 
allow manufacturers to continue to use current indirect TPMSs during 
that period and ease the implementation of the TPMS standard. The 
agency notes that, for vehicles already equipped with ABS, the 
installation of a current indirect TPMS is the least expensive way of 
complying with a TPMS standard. The compliance options and phase-in 
will also give manufacturers the flexibility needed to innovate and 
improve the performance of their TPMSs. This flexibility will improve 
the chances that ways can be found to improve the detection of under-
inflation as well as reduce the costs of doing so.
    The owner's manual for vehicles certified to either compliance 
option will be required to include written information explaining the 
purpose of the low tire pressure warning telltale, the potential 
consequences of driving on significantly under-inflated tires, the 
meaning of the telltale when it is illuminated, and the actions that 
drivers should take when the telltale is illuminated. In addition, the 
owner's manual in vehicles certified to the one-tire, 30 percent option 
will be required to include information on the inherent performance 
limitations of current indirect TPMSs because the agency anticipates 
that most indirect TPMSs installed to comply with that option will 
exhibit those limitations and because a vehicle owner survey indicates 
that a significant majority of drivers would be less concerned, to 
either a great extent or a very great extent, with routinely 
maintaining the pressure of their tires if their vehicle were equipped 
with a TPMS. Under both compliance options, the TPMS will be required 
to have a low tire pressure-warning telltale (yellow).
2. Part Two--November 2006 and Thereafter
    Beginning November 1, 2006, all passenger cars and light trucks, 
multipurpose passenger vehicles, and buses under 10,000 pounds GVWR 
will be required to comply with the requirements in the second part of 
this final rule. The agency will publish the second part of this final 
rule by March 1, 2005, in order to give manufacturers sufficient lead 
time before vehicles must meet the requirements.
    In anticipation of making the decision in part two of this final 
rule about the long-term requirements, the agency will leave the 
rulemaking docket open for the submission of new data and analyses. The 
agency also will conduct a study comparing the tire pressures of 
vehicles without any TPMS to the pressures of vehicles with TPMSs that 
do not comply with the four-tire, 25 percent compliance option. When 
completed, it will be placed in the docket for public examination. 
After consideration of the record compiled to this date, as 
supplemented by the results of the tire pressure study and any other 
new information submitted to the agency, NHTSA will issue the second 
part of this rule by March 1, 2005.
    Based on the record now before the agency, NHTSA tentatively 
believes that the four-tire, 25 percent option would best meet the 
mandate in the TREAD Act. However, it is possible that the agency may 
obtain or receive new information that is sufficient to justify a 
continuation of the compliance options established by the first part of 
this final rule, or the adoption of some other alternative.

[[Page 38707]]

E. Summary Comparison of the Preliminary Determination and the Final 
Rule

    The primary difference between the preliminary determination and 
the final rule is one of timing, instead of substance. The options and 
percentages of production for the phase-in years are unchanged.\3\ The 
final rule does differ from the preliminary determination in the timing 
of the agency's decision about the performance requirements for the 
years following the phase-in period.
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    \3\ The final rule does require that additional information be 
placed in the vehicle's owner manual.

 Summary Comparison of the Preliminary Determination and the Final Rule
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                                      Preliminary
                                     determination         Final rule
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Application...................  Passenger cars,         Same.
                                 trucks, multipurpose
                                 passenger vehicles,
                                 and buses with a GVWR
                                 of 10,000 pounds or
                                 less, except those
                                 vehicles with dual
                                 wheels on an axle.
Short-term (11/1/03--10/31/
 06):
Compliance Options............  Option 1: TPMS must     Same.
                                 warn the driver when
                                 the pressure in any
                                 single tire or in
                                 each tire in any
                                 combination of tires,
                                 up to a total of four
                                 tires, has fallen to
                                 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.
                                Option 2: TPMS must     Same.
                                 warn the driver when
                                 the pressure in any
                                 single tire has
                                 fallen to 30 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.
Phase-in Schedule.............  10% of a vehicle        Same.
                                 manufacturer's light
                                 vehicles will be
                                 required to comply
                                 with either
                                 compliance option
                                 during the first year
                                 (November 1, 2003 to
                                 October 31, 2004), 35
                                 percent during the
                                 second year (November
                                 1, 2004 to October
                                 31, 2005), and 65
                                 percent during the
                                 third year (November
                                 1, 2005 to October
                                 31, 2006).
Long-term (11/1/06 &
 thereafter):
Performance Requirements......  TPMS must warn the      Decision to be
                                 driver when the         made by March
                                 pressure in any         1, 2005.
                                 single tire or in
                                 each tire in any
                                 combination of tires,
                                 up to a total of four
                                 tires, has fallen to
                                 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.
------------------------------------------------------------------------

II. Background

A. The Transportation Recall Enhancement, Accountability, and 
Documentation Act

    Congress enacted the TREAD Act on November 1, 2000.\4\ Section 13 
of the TREAD Act mandated the completion of ``a rulemaking for a 
regulation to require a warning system in new motor vehicles to 
indicate to the operator when a tire is significantly under inflated'' 
within one year of the TREAD Act's enactment. Section 13 also requires 
the regulation to take effect within two years of the completion of the 
rulemaking.
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    \4\ Public Law 106-414.
    \5\ Tri-Level Study of the Causes of Traffic Accidents, Treat, 
J.R., et al. (1979) (Contract No. DOT HS 034-3-535), DOT HS 805 099, 
Washington, DC: U.S. Department of Transportation, National Highway 
Traffic Safety Administration.
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B. Previous Rulemaking on Tire Pressure Monitoring Systems

    NHTSA first considered requiring a ``low tire pressure warning'' 
device in 1970. However, the agency determined that the only warning 
device available at that time was an in-vehicle indicator whose cost 
was too high.
    During the 1970s, several manufacturers developed inexpensive, on-
tire warning devices. In addition, the price of in-vehicle warning 
devices dropped significantly.
    As a result, on January 26, 1981, NHTSA published an Advanced 
Notice of Proposed Rulemaking (ANPRM) soliciting public comment on 
whether the agency should propose a new Federal motor vehicle safety 
standard requiring each new motor vehicle to have a low tire pressure 
warning device which would ``warn the driver when the tire pressure in 
any of the vehicle's tires was significantly below the recommended 
operating levels.'' (46 FR 8062.)
    NHTSA noted in the ANPRM that under-inflation increases the rolling 
resistance of tires and, correspondingly, decreases the fuel economy of 
vehicles. Research data at the time indicated that the under-inflation 
of a vehicle's radial tires by 10 pounds per square inch (psi) reduced 
the fuel economy of the vehicle by 3 percent. Because of the worldwide 
oil shortages in the late 1970s and early 1980s, NHTSA was interested 
in finding ways to increase the fuel economy of passenger vehicles 
(i.e., passenger cars and multipurpose passenger vehicles). Since 
surveys by the agency showed that about 50 percent of passenger car 
tires and 13 percent of truck tires were operated at pressures below 
the vehicle manufacturer's recommended (placard) pressure, the agency 
believed that low tire pressure warning devices would encourage drivers 
to maintain their tires at the proper inflation level, thus maximizing 
their vehicles' fuel economy.
    Moreover, a 1977 study by Indiana University concluded that under-
inflated tires were a probable cause of 1.4 percent of all motor 
vehicle crashes.\5\ Based on that figure, and the approximately 18.3 
million motor vehicle crashes then occurring annually in the United 
States, the agency suggested that under-inflated tires were probably 
responsible for 260,000 crashes each year (1.4 percent x 18.3 million 
crashes).
    In the ANPRM, NHTSA sought answers from the public to several 
questions, including:
    (1) What tire pressure level should trigger the warning device?

[[Page 38708]]

    (2) Should the agency specify the type of warning device (i.e., on-
tire or in-vehicle) to be used?
    (3) What would it cost to produce and install an on-tire or in-
vehicle warning device?
    (4) What is the fuel saving potential of low tire pressure warning 
devices?
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    \5\ Tri-Level Study of the Causes of Traffic Accidents, Treat, 
J.R., et al. (1979) (Contract No. DOT HS 034-3-535), DOT HS 805 099, 
Washington, DC: U.S. Department of Transportation, National Highway 
Traffic Safety Administration.
---------------------------------------------------------------------------

    (5) What studies have been performed which would show cause and 
effect relationships between low tire pressure and auto crashes?
    (6) What would be the costs and benefits of a program to educate 
the public on the benefits of maintaining proper tire pressure?
    NHTSA terminated the rulemaking on August 31, 1981, because public 
comments indicated that the low tire pressure warning devices available 
at the time either had not been proven to be accurate and reliable (on-
tire devices) or were too expensive (in-vehicle devices). (46 FR 
43721.) The comments indicated that in-vehicle warning devices had been 
proven to be accurate and reliable, but would have had a retail cost of 
$200 (in 1981 dollars) per vehicle. NHTSA stated, ``Such a cost 
increase cannot be justified by the potential benefits, although those 
benefits might be significant.'' (46 FR 43721.) The comments also 
indicated that on-tire warning devices cost only about $5 (in 1981 
dollars), but they had not been developed to the point where they were 
accurate and reliable enough to be required. The comments also 
suggested that on-tire warning devices were subject to damage by road 
hazards, such as ice and mud, as well as scuffing at curbs. Despite 
terminating the rulemaking, the agency stated that it still believed 
that ``[m]aintaining proper tire inflation pressure results in direct 
savings to drivers in terms of better gas mileage and longer tire life, 
as well as offering increased safety.'' (46 FR 43721.)

C. Summary of the Notice of Proposed Rulemaking

    On July 26, 2001, the agency published the NPRM proposing to 
establish a standard for TPMSs pursuant to section 13 of the TREAD Act. 
(66 FR 38982.) The agency proposed two alternative versions of the 
standard.
    The two alternatives differed in two important respects: in how 
they defined ``significantly under-inflated,'' and in the number of 
significantly under-inflated tires that they would be required to be 
able to detect at any one time. The first alternative (four tires, 20 
percent) would have defined ``significantly under-inflated'' as the 
tire pressure 20 percent or more below the placard pressure, or a 
minimum level of pressure specified in the standard, whichever was 
higher. It would have required the low tire pressure warning telltale 
to illuminate when any tire, or when each tire in any combination of 
tires, on the vehicle became significantly under-inflated.
    The second alternative (three tires, 25 percent) would have defined 
``significantly under-inflated'' as the tire pressure 25 percent or 
more below the placard pressure, or a minimum level of pressure 
specified in the standard, whichever was higher. The minimum levels of 
pressure were the same in both proposed alternatives. The alternative 
would have required the low tire pressure warning telltale to 
illuminate when any tire, or when each tire in any combination of 
tires, up to a total of three tires, became significantly under-
inflated.
    In most other respects, the two alternatives were identical. Both 
would have required passenger cars, multipurpose passenger vehicles, 
trucks, and buses with a GVWR of 4,536 kilograms (10,000 pounds) or 
less, manufactured on or after November 1, 2003, to be equipped with a 
TPMS and a low tire pressure warning telltale (yellow) to alert the 
driver. They would have required the telltale to illuminate within 10 
minutes of driving after any tire on the vehicle became significantly 
under-inflated. They would have required the telltale to remain 
illuminated as long as any of the vehicle's tires remained 
significantly under-inflated, and the key locking system was in the 
``On'' (``Run'') position. They would have required that the telltale 
be deactivatable, manually or automatically, only when the vehicle no 
longer had a tire that was significantly under-inflated. They would 
have required the TPMS in each vehicle to be compatible with all 
replacement or optional tires/rims of the size recommended for that 
vehicle by the vehicle manufacturer, i.e., each TPMS would have been 
required to continue to meet the requirements of the standard when the 
vehicle's original tires were replaced with tires of any optional or 
replacement size(s) recommended for the vehicle by the vehicle 
manufacturer. Finally, they would have required vehicle manufacturers 
to provide written instructions, in the owner's manual if one is 
provided, explaining the purpose of the low tire pressure warning 
telltale, the potential consequences of significantly under-inflated 
tires, and what actions drivers should take when the low tire pressure 
warning telltale is illuminated.
    NHTSA believed that the only currently available TPMSs that would 
have been able to meet the requirements of the four-tire, 20 percent 
alternative were direct TPMSs. There were two reasons for this belief. 
First, currently available indirect TPMSs typically cannot detect 
significant under-inflation until the pressure in one of the vehicle's 
tires is about 30 percent below the pressure in at least some of the 
other tires. Second, they cannot detect when all four tires lose 
inflation pressure equally.
    The agency believed that both currently available direct TPMSs and 
improved indirect TPMSs, but not current indirect TPMSs, would have 
been able to meet the requirements of the three-tire, 25 percent 
alternative.
    In the NPRM, NHTSA anticipated that vehicle manufacturers would 
minimize their costs of complying with the three-tire, 25 percent 
alternative by installing improved indirect TPMSs in vehicles already 
equipped with ABSs and direct TPMSs in vehicles without ABSs. For 
vehicles already equipped with an ABS, the cost of modifying that 
system to serve the additional purpose of indirectly monitoring tire 
pressure would be significantly less than the cost of adding a direct 
TPMS. For vehicles not so equipped, adding a direct TPMS would be 
significantly less expensive than adding ABS to monitor tire pressure.
    For the NPRM, NHTSA had two sets of data, one from Goodyear and 
another from NHTSA's Vehicle Research and Test Center (VRTC), on the 
effect of under-inflated tires on a vehicle's stopping distance. The 
Goodyear data indicated that a vehicle's stopping distance on wet 
surfaces is significantly reduced when its tires are properly inflated, 
as compared to when its tires are significantly under-inflated. The 
VRTC data indicated little or no effect on a vehicle's stopping 
distance. For purposes of the NPRM, NHTSA used the Goodyear data to 
establish an upper bound of benefits and the VRTC data to establish a 
lower bound. The benefit estimates below are the mid-points between 
those upper and lower bounds.
    NHTSA estimated that the four-tire, 20 percent alternative would 
have prevented 10,635 injuries and 79 deaths at an average net cost of 
$23.08 per vehicle.\6\ NHTSA estimated that the

[[Page 38709]]

three-tire, 25 percent alternative would have prevented 6,585 injuries 
and 49 deaths at an average net cost of $8.63 per vehicle.\7\ NHTSA 
estimated that the net cost per equivalent life saved would have been 
$1.9 million for the four-tire, 20 percent alternative and $1.1 million 
for the three-tire, 25 percent alternative.
---------------------------------------------------------------------------

    \6\ 6 The range of injuries prevented was 0 to 21,270, and the 
range of deaths prevented was 0 to 158. These benefit estimates did 
not include deaths and injuries prevented due to reductions in 
crashes caused by blowouts and skidding/loss of control because the 
agency was unable to quantify those benefits at the time the NPRM 
was published. For this final rule, the agency was able to quantify 
those benefits. They are discussed in the Benefits section below. 
Net costs included $66.33 in vehicle costs minus $32.22 in fuel 
savings and $11.03 in tread wear savings. These cost estimates did 
not include maintenance costs. For this final rule, the agency has 
estimated maintenance costs. They are discussed in the Costs section 
below.
    \7\ The range of injuries prevented was 0 to 13,170, and the 
range of deaths prevented was 0 to 97. Net costs included $30.54 in 
vehicle costs minus $16.40 in fuel savings and $5.51 in tread wear 
savings. These estimates did not include maintenance costs. The 
agency has estimated maintenance costs for this final rule.
---------------------------------------------------------------------------

    Finally, the agency requested comments on whether a compliance 
phase-in with carry-forward credits would be appropriate. The agency 
suggested a phase-in period of 35 percent of production in the first 
year (2003), 65 percent in the second year, and 100 percent in the 
third year.

D. Summary of Public Comments on Notice

    The agency received comments from tire, vehicle, and TPMS 
manufacturers, consumer advocacy groups, and the general public. In 
general, the tire manufacturers' comments, including the comments of 
the international tire industry associations European Tyre and Rim 
Technical Organisation (ETRTO), Japan Automobile Tyre Manufacturers 
Association (JATMA), and International Tire & Rubber Association 
(ITRA), echoed the comments of the Rubber Manufacturers Association 
(RMA). In general, the vehicle manufacturers' comments, including the 
comments of the Association of International Automobile Manufacturers 
(AIAM), were similar to the comments of the Alliance of Automobile 
Manufacturers (Alliance).
    The tire manufacturers generally supported the four-tire, 20 
percent alternative. The vehicle manufacturers generally supported 
requirements that would permit both direct and current indirect TPMSs 
to comply. TPMS manufacturers generally supported the alternative that 
would allow the type of system they manufacture. The consumer advocacy 
groups--Consumers Union and Advocates for Highway and Auto Safety 
(Advocates) supported by Public Citizen, Consumer Federation of 
America, and Trauma Foundation--generally supported the four-tire, 20 
percent alternative. The general public was about evenly divided 
between those who supported and those who opposed a Federal standard 
requiring TPMSs.
    The major issues discussed by the commenters are summarized below. 
The comments are addressed in the discussion of the final rule below
1. Vehicles Covered
    The agency proposed to require TPMSs on passenger cars, 
multipurpose passenger vehicles, trucks, and buses with a GVWR of 4,536 
kilograms (10,000 pounds) or less. The agency did not propose to 
require TPMSs on motorcycles, trailers, or low speed vehicles, or on 
medium (10,001-26,000 pounds GVWR) vehicles, or heavy (greater than 
26,000 pounds GVWR) vehicles for reasons explained in the NPRM.
    The Alliance recommended that the agency limit the applicability of 
the standard to these types of vehicles to those having a GVWR of 3,856 
kilograms (8,500 pounds or less). The Alliance stated that the majority 
of vehicles above 8,500 pounds GVWR are used commercially. The Alliance 
argued that those vehicles are maintained on a regular basis and do not 
need a TPMS to assist in maintaining proper inflation pressure in the 
vehicles' tires.
    The Alliance also recommended that the agency explicitly exclude 
incomplete vehicles, i.e., vehicles that are built in more than one 
stage, from the standard. Normally, the first-stage vehicle 
manufacturer is responsible for certifying that all vehicle systems 
that are not directly modified by subsequent-stage manufacturers meet 
all Federal motor vehicle safety standards. The Alliance stated that in 
the case of direct TPMSs, the first-stage manufacturer will be unable 
to guarantee that, even if physically undisturbed, a non-defective TPMS 
will function as designed after vehicle modifications (such as adding 
metal hardware to the vehicle or lengthening its wheelbase) are made by 
subsequent-stage manufacturers.
    Advocates recommended that the agency expand the application of the 
standard to include medium (10,001-26,000 pounds GVWR) and heavy (over 
26,000 pounds) trucks and buses. Advocates stated that tire under-
inflation is a pervasive problem with these vehicles, especially given 
the high percentage of these vehicles that are equipped with re-treaded 
tires.
2. Phase-In Options and Long-Term Requirements
    a. Definition of ``Significantly Under-Inflated''
    RMA recommended that the agency define ``significantly under-
inflated'' as any inflation pressure that is less than the pressure 
required to carry the actual vehicle load on the tire per tire industry 
standards (or any pressure required to carry the maximum vehicle load 
on the tire if the actual load is unknown), or the minimum activation 
pressure specified in the standard, whichever is higher. RMA argued 
that some vehicles have a placard pressure that is barely adequate to 
carry the vehicle's maximum load. If the tire pressure falls 20 or 25 
percent below the placard pressure, the tire pressure will be 
insufficient to carry the load. RMA stated that the definition of 
``significantly under-inflated'' should not be tied to placard pressure 
unless the standard includes a requirement for all vehicles to have a 
reserve in the placard pressure above a specified minimum (e.g., 20 or 
25 percent).
    RMA also recommended that the agency change the minimum activation 
pressures for P-metric standard load tires from 20 to 22 psi and for P-
metric extra load tires from 23 to 22 psi. Finally, RMA recommended 
that the agency change the ``Maximum Pressure'' heading in Table 1 to 
``Maximum or Rated Pressure'' because light truck tires are not subject 
to maximum permissible inflation pressure labeling requirements. RMA 
recommended that the agency change the rated pressure for Load Range E 
tires from 87 to 80 psi. Finally, RMA, supported by the Retread/Repair 
Industry Government Advisory Council (RIGAC),\8\ recommended that the 
agency adopt, in this rulemaking proceeding, an amendment to upgrade 
Standard No. 109, ``New Pneumatic Tires,'' by requiring that ``a tire 
for a particular vehicle must have sufficient inflation and load 
reserve, such that an inflation pressure 20 or 25 percent less than the 
vehicle manufacturer's recommended inflation pressure is sufficient for 
the vehicle maximum load on the tire, as defined by FMVSS-110.'' \9\
---------------------------------------------------------------------------

    \8\ RIGAC consists of representatives from the Tire Association 
of North America (TANA), Tread Rubber Manufacturers Group (TRMG), 
ITRA, and RMA.
    \9\ Standard No. 110 specifies requirements for tire selection 
to prevent tire overloading.
---------------------------------------------------------------------------

    The ITRA recommended that the agency consider only direct TPMSs. 
The ITRA stated that indirect TPMSs have too many limitations, 
including the inability to detect when all four of a vehicle's tires 
are significantly under-inflated. The ITRA claimed that, although 
direct TPMSs are more expensive than indirect TPMSs, their cost is 
minor when compared to their safety, handling, tread wear, and fuel 
economy benefits.
    The Alliance recommended that the agency define ``significantly 
under-inflated'' as any inflation pressure 20 percent below a tire's 
load carrying

[[Page 38710]]

limit, as determined by a tire industry standardizing body (such as the 
Tire and Rim Association) or the minimum activation pressure specified 
in the standard, whichever is higher. The Alliance agreed with the 
agency's minimum activation pressure of 20 psi for P-metric standard 
load tires. The Alliance cited data from tests performed by RMA 
indicating that the average tire was able to operate at high speeds 
(120 and 140 km/h) at load-inflation conditions more extreme than the 
worst case that the Alliance proposal would allow.
    The Alliance also stated that a 25 percent differential from 
placard pressure would be inadequate to allow the use of indirect 
TPMSs. The Alliance claimed that a minimum of 30 percent differential 
is necessary to ensure accuracy with an indirect TPMS and avoid 
excessive nuisance warnings.
    The AIAM recommended that the agency define ``significantly under-
inflated'' as any pressure more than 30 percent below the placard 
pressure. Alternatively, the AIAM suggested that the agency use the 
load-carrying limit of the tire as defined by a tire industry 
standardizing body as the baseline for determining the warning 
threshold.
    Several manufacturers indicated that they are either developing or 
could develop indirect or hybrid TPMSs that perform better than current 
indirect TPMSs. In its comments on the NPRM, TRW Automotive Electronics 
(TRW), which manufactures both direct and indirect TPMSs, stated that 
it could, in concept, combine direct and indirect TPMS technologies to 
produce a hybrid TPMS that performs better than TRW's current indirect 
TPMS. TRW stated this could be accomplished by adding the equivalent of 
two direct pressure-monitoring sensors and a radio frequency receiver 
to an indirect TPMS. TRW suggested that this hybrid TPMS could comply 
detect 25 under-inflation for about 60 percent of the cost of a full 
direct TPMS. However, it did not indicate whether it had any plans to 
develop a hybrid system.
    Sumitomo Rubber Industries, which manufactures indirect TPMSs, 
indicated that indirect TPMSs will be able to detect a 25 percent 
differential in inflation pressure.
    Toyota, which uses an indirect TPMS on its Sienna van, stated that 
its next generation of indirect TPMSs (i.e., TPMSs not available for 
current production) would be able to detect a 20 percent differential 
in tire pressure by monitoring the resonance frequency as well as the 
dynamic radius changes of the tires. However, Toyota stated that this 
performance will be achieved only under ideal conditions, i.e., the 
vehicle is traveling in a relatively straight line at 30 to 60 km/h for 
at least 20 minutes. Thus, Toyota recommended that the agency adopt the 
Alliance proposal of 30 percent under-inflation. Toyota also stated 
that its next generation of indirect TPMSs would be able to detect 
significant under-inflation in all four tires. Toyota was not certain 
when its next generation of indirect TPMSs will be ready for 
implementation.
    Advocates supported the definition of ``significantly under-
inflated'' contained in the four-tire, 20 percent alternative, i.e., 
any pressure 20 percent or more below the placard pressure, or the 
minimum activation pressure specified in the standard. Advocates also 
supported the agency's minimum activation pressures.
    b. Number of Tires Monitored
    Advocates, the ITRA, and RMA recommended that the agency require 
TPMSs to be able to detect when all four of a vehicle's tires become 
significantly under-inflated. RMA argued that it is very likely that 
all four tires will lose air pressure at a similar rate and become 
significantly under-inflated within a six-month period.\10\ RMA stated 
that drivers would rely heavily on TPMSs for tire pressure maintenance, 
which will make this scenario even more likely.
---------------------------------------------------------------------------

    \10\ RMA stated that normal air pressure loss is approximately 1 
to 2 psi per month.
---------------------------------------------------------------------------

    The Alliance and AIAM recommended that the agency require only that 
TPMSs be able to detect significant under-inflation in a single tire. 
The Alliance argued that TPMSs are not meant to replace the normal tire 
maintenance that would detect pressure losses due to natural leakage 
and permeation. Instead, TPMSs are intended to detect a relatively slow 
leak due to a serviceable condition, such as a nail through the tread 
or a leaky valve stem. Since such leaks rarely affect more than one 
tire simultaneously, the Alliance argued, it is sufficient to require 
only that TPMSs be able to detect a single significantly under-inflated 
tire. In further support of this position, the Alliance argued that 
tires do not lose pressure at the same rate.
    As noted above, TRW commented that a hybrid TPMS could be developed 
that would be capable of monitoring all four of a vehicle's tires. 
According to TRW, a hybrid system would involve installing two direct 
pressure sensors, one in a front wheel and one in a back wheel located 
diagonally from each other (e.g., the front left and back right 
wheels), on a vehicle already equipped with an indirect TPMS. The 
pressure sensors would directly monitor the pressure in those two 
tires, while the indirect TPMS would use the wheel speed sensors to 
indirectly monitor the pressure in the other two tires. This would 
solve the problem indirect TPMSs have in detecting when two tires on 
the same axle or the same side of the vehicle become significantly 
under-inflated because a direct pressure sensor will be in a wheel on 
each axle and on each side of the vehicle. It would also solve the 
problem indirect TPMSs have in detecting when all four tires become 
significantly under-inflated.
    Advocates and RMA also recommended that the agency require TPMSs to 
monitor a vehicle's spare tire. RMA argued that the spare tire should 
be monitored to ensure its functionality, if and when it is needed. 
Advocates stated, ``Vehicle owners chronically neglect to maintain 
minimal air pressure in spare tires.''
    The Alliance recommended that the agency require only that TPMSs 
monitor full-size, matching spare tires, and only when they are 
installed on the vehicle (i.e., not when they are stowed). The Alliance 
stated that temporary-use spare tires, including full-size, non-
matching and compact spare tires, are not intended to be part of the 
normal tire rotation cycle for the vehicle. Because these temporary-use 
spare tires degrade the aesthetic appearance of a vehicle or have speed 
and distance limitations, vehicle owners normally replace them quickly. 
Thus, the Alliance recommended that the agency not require TPMSs to 
monitor temporary-use tires, whether stowed or installed on the 
vehicle.
    RMA supported the agency's proposed requirement that TPMSs function 
properly with all replacement tires and rims of the size(s) recommended 
by the vehicle manufacturer. Advocates recommended that the agency 
require TPMSs to function properly with all replacement tires and rims, 
regardless of size.
    The Alliance recommended that the agency require only that TPMSs 
function properly with those tires and rims offered as original or 
optional equipment by the vehicle manufacturer. The Alliance stated 
that there are a large number of replacement brands and types of tires 
and rims with different dynamic rolling radii, size variations, load 
variations, and temperature characteristics. The Alliance argued that 
since vehicle manufacturers do not control tire compliance for 
aftermarket tires and rims, they could not guarantee that the TPMS will 
work, or will work with the same level of precision, in all cases.

[[Page 38711]]

3. Lead Time
    The Alliance and most vehicle manufacturers recommended the 
following four-year phase-in schedule: 15 percent of a manufacturer's 
affected products equipped with a semi- or fully-compliant TPMS in the 
first year; 35 percent in the second year; 70 percent in the third 
year; and 100 percent of a manufacturer's affected products equipped 
with a fully compliant TPMS in the final year. According to the 
Alliance, a semi-compliant TPMS is one that meets all but specified 
interface requirements, i.e., those concerning the display of 
information about under-inflation, and would be allowed only during the 
phase-in period. The Alliance and AIAM also recommended that the agency 
provide credits for early introduction of TPMSs to encourage early 
implementation of the standard.
    TRW supported the agency's four-year phase-in period. TRW stated 
that direct TPMSs are ready so that manufacturers could start 
production to meet such a phase-in. However, TRW stated that the 
improvements in indirect TPMSs that will be necessary to meet the 
requirements of this final rule would make it difficult to meet the 
compliance date of November 1, 2003.
    Ford Motor Company (Ford) commented that its recent experience with 
direct TPMSs demonstrates that this technology still needs a thorough 
prove-out. Ford stated that when it tested 138 direct pressure sensors 
on 30 vehicles, nine sensors experienced a malfunction. This translates 
to a sensor failure rate of 6.5 percent. However, Ford stated that if 
the final rule required five sensors per vehicle (all four tires plus 
the spare tire), nearly 33 percent of vehicles could experience the 
failure of at least one sensor. Ford recommended that the agency adopt 
the phase-in schedule set forth by the Alliance.
    Vehicle Services Consulting, Inc. (VSC), which submitted comments 
on behalf of small volume vehicle manufacturers (i.e., those 
manufacturers who produce fewer than 5,000 vehicles worldwide each 
year), recommended that the agency provide phase-in discretion so that 
small volume manufacturers have until the end of the phase-in period 
before having to comply with the TPMS requirements. VSC claimed that 
small volume manufacturers could not obtain the TPMS technology at the 
same time as large volume manufacturers.
4. Reliability
    In the NPRM, the agency noted that the components of direct TPMSs, 
especially when tires are taken off the rim, might be susceptible to 
damage. The agency requested comments on the likelihood of such damage. 
TRW stated:

    Direct TPMSs are relatively new systems and, therefore, the 
likelihood of damage during driving or maintenance is unknown. 
However, direct TPMS sensors are designed to minimize the likelihood 
of damage during driving or maintenance operations. Most sensors are 
valve-mounted and rest in the drop center well of the rim, and are 
contoured to minimize the likelihood of damage during tire 
servicing. They can be packaged in a high impact plastic material, 
which can withstand high G forces and mechanical vibration/shock 
levels associated with the tire/wheel system. The likelihood of 
damage during operation is also minimized by the selected mounting 
location and the protection offered by the rim during flat 
conditions. These factors, combined with training for service center 
technicians, should reduce the overall likelihood of damage.

    Beru Corporation, which manufacturers direct TPMSs, stated that it 
had sold over 800,000 direct TPMS wheel electronics and had received no 
reports of damage during operation or failures due to mounting error.
    The European Community (EC) supported a rulemaking requiring TPMSs. 
The EC Stated, ``The European Community is convinced (as is the NHTSA) 
of the appropriateness of a regulation in this field, and of its 
justification for the safety of road users.'' The EC stressed ``the 
paramount importance of reliability and accuracy of the technology.'' 
The EC stated that ``a temperature correction device might be a 
necessary feature in order to guarantee the reliability and accuracy of 
the device.''
5. Costs and Benefits Estimates
    The Alliance stated that the benefits NHTSA estimated resulting 
from a reduction in stopping distance were based on three principal 
conclusions: (1) Properly inflated tires result in shorter stopping 
distances than under-inflated tires; (2) these shorter stopping 
distances have equal safety benefits in all types of crashes and under 
all environmental conditions; and (3) the benefits of shorter stopping 
distances associated with properly-inflated tires will be greater for 
direct TPMSs than for indirect TPMSs. The Alliance argued that each of 
these conclusions is highly questionable and not supported by the 
information in the rulemaking record.
    The Alliance noted that in estimating the safety benefits resulting 
from stopping distance reductions, the agency relied on Goodyear data. 
The Alliance argued that these data ``are neither conclusive with 
respect to the effect of under-inflation on stopping distance, nor 
reproducible according to the agency's own study demonstrating that 
there is no significant effect of tire under-inflation on stopping 
distance.'' The Alliance also argued that even if the Goodyear data 
were valid, NHTSA's benefits estimates must be adjusted to claim 
benefits only for vehicles experiencing the same conditions as those in 
the Goodyear tests, i.e., all four of the vehicle's tires are at 17 psi 
or below and on wet pavement.\11\ The Alliance questioned NHTSA's 
assumption that 80 percent of drivers would respond appropriately to a 
direct TPMS, but that only 60 percent of drivers would respond 
appropriately to an indirect TPMS. The Alliance argued that there was 
no evidence in the record supporting this assumption.
---------------------------------------------------------------------------

    \11\ Goodyear conducted its tests on pavement with 0.05 inch 
water on the surface and found significant effects on stopping 
distance only when the pressure in the vehicle's tires was lowered 
to 17 psi.
---------------------------------------------------------------------------

    Finally, the Alliance agreed that TPMSs should produce some of the 
unquantified benefits listed in the NPRM. However, the Alliance stated 
that there was no evidence that these benefits would be greater for 
direct TPMSs than for indirect TPMSs.
    The ITRA stated that when developing training programs, it looks 
closely at tire performance and has the opportunity to analyze a 
significant number of tires that failed in service. They find that the 
single most common cause of tire failure is under-inflation. Thus, the 
ITRA claimed that the agency's benefits estimates may be under-stated.
    TRW stated that current indirect TPMSs would have to be upgraded to 
meet the requirements of the three-tire, 25 percent alternative. TRW 
estimated that these upgrades would increase the cost of indirect TPMSs 
to 60 percent of the cost of a direct TPMS.\12\
---------------------------------------------------------------------------

    \12\ This estimate would apply only to vehicles that were 
already equipped with ABS.
---------------------------------------------------------------------------

    IQ-mobil Electronics, a TPMS manufacturer in Germany, commented 
that it has developed ``a batteryless transponder chip'' that ``costs 
half as much as the battery transmitter it replaces,'' thus reducing 
``high replacement costs for the tire transmitter, and an annual 
environmental burden of millions of batteries.''

E. Submission of Draft Final Rule to OMB

    Since this final rule is considered ``significant'' under Executive 
Order 12866, Regulatory Planning and Review, it was subject to review 
by the Office of Management and Budget (OMB) under that Order. The 
agency submitted a draft

[[Page 38712]]

final rule to OMB on December 18, 2001.
    The draft final rule specified short and long-term performance 
requirements.\13\ For the short term, it specified a phase-in of the 
TPMS requirements beginning November 1, 2003. During the phase-in, the 
draft final rule permitted vehicles to comply with either a four-tire, 
25 percent option, which essentially would have required manufacturers 
to install direct TPMSs or improved indirect TPMSs, or a one-tire, 30 
percent option, which would have permitted manufacturers to install 
either direct TPMSs or any type of indirect TPMSs, including current 
indirect TPMSs. For the long-term, the period beginning November 1, 
2006, the requirements of the four-tire, 25 percent option would have 
become mandatory for all vehicles subject to the TPMS standard.
---------------------------------------------------------------------------

    \13\ The rationales for the provisions of that draft final rule 
are discussed below in section VI.A., ``Summary of Preliminary 
Determination about the Final Rule.''
---------------------------------------------------------------------------

    As explained further below in section V.A. ``Alternative Long-Term 
Requirements Analyzed in Making Preliminary Determination,'' NHTSA 
analyzed three alternatives for the long term requirement in developing 
the draft final rule: a four-tire, 20 percent alternative, a three-
tire, 25 percent alternative, and a four-tire, 25 percent alternative.

F. OMB Return Letter

    After reviewing the draft final rule, OMB returned it to NHTSA for 
reconsideration, with a letter explaining its reasons for doing so, on 
February 12, 2002.\14\
---------------------------------------------------------------------------

    \14\ A copy of the return letter has been placed in the docket 
(Docket No. NHTSA-2000-8572-202). The letter also is available 
electronically at www.whitehouse.gov/omb/inforeg/dot_revised_tire_rtnltr.pdf.
---------------------------------------------------------------------------

    In the letter, OMB stated its belief that the draft final rule and 
accompanying regulatory impact analysis did not adequately demonstrate 
that the agency had selected the best available method of improving 
overall vehicle safety. OMB said further that: NHTSA should base its 
decision about the final rule on overall vehicle safety, instead of 
just tire safety; while direct TPMSs can detect under-inflation under a 
greater variety of circumstances than indirect TPMSs, the indirect 
system captures a substantial portion of the benefit provided by direct 
systems; NHTSA should consider a fourth alternative for the long-term 
requirement, a one-tire, 30 percent compliance option, indefinitely, 
since it would allow vehicle manufacturers to install current indirect 
TPMSs; NHTSA, in analyzing long-term alternatives, should consider both 
their impact on the availability of ABS as well as the potential safety 
benefits of ABS; and that NHTSA should provide a better explanation of 
the technical foundation for the agency's safety benefits estimates and 
subject those estimates to sensitivity analyses.

G. Public Comments on OMB's Return Letter

    Consumers Union (CU) and Public Citizen (PC) submitted comments on 
the OMB return letter.\15\
---------------------------------------------------------------------------

    \15\ Both letters have been placed in the docket. The CU letter 
is Docket No. NHTSA-2000-8572-204, and the PC letter is Docket No. 
NHTSA-2000-8572-199.
---------------------------------------------------------------------------

    CU stated that direct TPMSs offer significant safety advantages 
over indirect TPMSs. CU recently performed tire air leakage testing and 
found that all four tires on a vehicle will likely lose pressure at a 
similar rate.\16\ CU said that direct TPMSs could detect such pressure 
losses, while indirect TPMSs could not.
---------------------------------------------------------------------------

    \16\ CU tested three samples of 36 tire models over a six-month 
period. CU mounted the tires on new rims and inflated the tires to 
30 psi. Then CU stored the tires indoors at room temperature for six 
months and checked their inflation pressure each month. After six 
months, the average pressure loss was about 4.4 psi. A copy of CU's 
test procedures and the test results has been placed in the docket. 
(Docket No. NHTSA-2000-8572-203.)
---------------------------------------------------------------------------

    CU questioned OMB's returning the TPMS final rule and asking NHTSA 
to consider the potential benefits of ABS in making a final decision on 
TPMS requirements. CU stated:

    We cannot understand the logic of delaying an important safety 
measure like direct tire pressure monitoring systems while NHTSA 
studies issues related to a less effective alternative because that 
alternative might encourage automakers to make ABS more widely 
available.

    Finally, CU stated that, while Congress mandated that NHTSA issue a 
regulation for TPMSs, Congress did not mandate that the agency issue a 
regulation requiring ABS to be installed in all vehicles.
    PC also supported the four-tire, 20 percent alternative. PC argued 
that indirect TPMSs have shortcomings, including:
     They can detect under-inflation only if one tire is more 
than 25 percent less inflated than the other tires.
     They cannot detect when all four tires are equally under-
inflated, a likely scenario if the tires are purchased or checked at 
the same time.
     They also cannot detect when two tires on the same side of 
the vehicle or the same axle are under-inflated, but can detect when 
diagonal tires are under-inflated.
    PC also objected to OMB's returning the TPMS final rule and asking 
NHTSA to consider the potential benefits of ABS in making a final 
decision on TPMS requirements. PC questioned OMB's return letter, 
arguing that it employs

    unproven assumptions about the cost and market effects of 
combining indirect systems with a requirement for anti-lock brakes 
(ABS) (a long-controversial area outside the focus of the agency's 
current rulemaking mandate), which, in turn, has only statistically 
insignificant and highly disputed safety effects.

    PC also questioned the potential benefits of ABS cited by OMB. In 
response to OMB's reliance on a study by Charles Farmer, the PC 
asserted that Mr. Farmer

    found that ABS had no statistically significant effect on crash 
fatalities. [Emphasis original.] Farmer was unable to determine 
whether ABS ultimately saved or cost lives across the vehicle fleet, 
making the ``between 4 and 9 percent reduction'' in crash fatalities 
[cited in the OMB letter] a statistical blip that may actually be 
zero percent.

H. Congressional Hearing

    On February 28, 2002, the House Committee on Energy and Commerce 
held an oversight hearing on the implementation of the TREAD Act. 
During the hearing, several Congressmen discussed their expectations 
for the TPMS rulemaking. Expressing concern about the cumulative damage 
done to a tire that is run while under-inflated, Congressman Tom Sawyer 
asked whether a warning threshold of 25 percent below placard pressure 
was low enough. Given the potential for catastrophic failure of tires 
run too long while under-inflated, the Congressman stated that it was 
important that the TPMS not encourage drivers to drive on under-
inflated tires.
    Congressman Markey, the sponsor of the amendment that added the 
TPMS mandate to the TREAD Act, indicated that the reliance of drivers 
on the TPMS warning light could lead to safety problems if the TPMS 
does not provide sufficient warnings. He acknowledged that, during the 
consideration of the TPMS amendment, he had mentioned a TPMS that was 
then in use (an ABS-based TPMS on the Toyota Sienna). He said that 
while any TPMS was acceptable during the initial implementation period 
for the TPMS requirements, the real intent of the amendment is to 
provide a warning in all instances.

III. Safety Problem

    Many vehicles have significantly under-inflated tires, primarily 
because drivers infrequently check their

[[Page 38713]]

vehicles' tire pressure. Other contributing factors are the difficulty 
of visually detecting when a tire is significantly under-inflated and 
the loss of tire pressure due to natural leakage and seasonal climatic 
changes.

A. Infrequent Driver Monitoring of Tire Pressure

    Surveys have shown that most drivers check the inflation pressure 
in their vehicles' tires infrequently. For example, in September 2000, 
the Bureau of Transportation Statistics (BTS) conducted an omnibus 
survey for NHTSA. One of the questions posed was: ``How often do you, 
or the person who checks your tires, check the air pressure in your 
tires?'' The answers indicated that 29 percent of the respondents 
stated that they check the air pressure in their tires monthly; another 
29 percent stated that they check the air pressure only when one or 
more of their vehicle's tires appears under-inflated; 19 percent stated 
that they only have the air pressure checked when the vehicle is 
serviced; 5 percent stated that they only check the air pressure before 
taking their vehicle on a long trip; and 17 percent stated that they 
check the air pressure on some other occasion. Thus, 71 percent of the 
respondents stated that they check the air pressure in the vehicles' 
tires less than once a month.\17\
---------------------------------------------------------------------------

    \17\ The agency notes that it seems likely that the respondents 
in both of the surveys cited overstated the frequency with which 
they check tire pressure, particularly given the fact that these 
surveys were conducted during the height of publicity about tire 
failures on sport utility vehicles in the late 2000 and early 2001.
---------------------------------------------------------------------------

    In addition, NHTSA's National Center for Statistics and Analysis 
(NCSA) conducted a survey in February 2001. The survey was designed to 
assess the extent to which passenger vehicle drivers are aware of the 
recommended air pressure for their vehicles' tires, if drivers monitor 
air pressure, and to what extent actual tire pressure differs from 
placard pressure.
    Data was collected through the infrastructure of the National 
Accident Sampling System--Crashworthiness Data System (NASS-CDS). The 
NASS-CDS consists of 24 Primary Sampling Units (PSUs) located across 
the country. Within each PSU, a random selection of zip codes was 
obtained from a list of eligible zip codes. Within each zip code, a 
random selection of two gas stations was obtained.
    A total of 11,530 vehicles were inspected at these gas stations. 
This total comprised 6,442 passenger cars, 1,874 sports utility 
vehicles (SUVs), 1,376 vans, and 1,838 pick-up trucks. For analytical 
purposes, the data were divided into three categories: (1) Passenger 
cars; (2) pick-up trucks, SUVs, and vans with P-metric tires; and (3) 
pick-up trucks, SUVs, and vans with either light truck (LT) or 
flotation tires.
    Drivers were asked how often they normally check their tires to 
determine if they are properly inflated. Their answers are in the 
following table:

------------------------------------------------------------------------
                                                   Drivers of pick-up
                                                 trucks, SUVs, and vans
                                    Drivers of             (%)
    How often is tire pressure      passenger  -------------------------
             checked?                cars (%)                   LT or
                                                  P-metric    flotation
                                                   tires        tires
------------------------------------------------------------------------
Weekly...........................         8.76         8.69         8.16
Monthly..........................        21.42        25.19        39.88
When they seem low...............        25.63        23.58        15.59
When serviced....................        30.18        27.72        25.54
For long trip....................         0.99         2.39         2.17
Other............................         6.46         8.27         6.97
Do not check.....................         6.56         4.16         1.69
------------------------------------------------------------------------

    These data indicate that only about 30 percent of drivers of 
passenger cars, 34 percent of drivers of pick-up trucks, SUVs, and vans 
with P-metric tires, and 48 percent of drivers of pick-up trucks, SUVs, 
and vans with either LT or flotation tires claim that they check the 
air pressure in their vehicles' tires at least once a month.

B. Loss of Tire Pressure Due to Natural and Other Causes

    According to data from the tire industry, 85 percent of all tire 
air pressure losses are the result of slow leaks that occur over a 
period of hours, days, or months. Only 15 percent are rapid air losses 
caused by contact with a road hazard, e.g., when a large nail that does 
not end up stuck in the tire punctures a tire.
    Slow leaks may be caused by many factors. Tire manufacturers 
commented that tires typically lose air pressure through natural 
leakage and permeation at a rate of about 1 psi per month. Testing by 
CU supports those comments. In addition, tire manufacturers said that 
seasonal climatic changes result in air pressure losses on the order of 
1 psi for every 10 degree F decrease in the ambient temperature. Slow 
leaks also may be caused by slight damage to a tire, such as a road 
hazard that punctures a small hole in the tire or a nail that sticks in 
the tire. NHTSA has no data indicating how often any of these causes 
results in a slow leak.

C. Percentage of Motor Vehicles With Under-Inflated Tires

    During the February 2001 survey, NASS-CDS crash investigators 
measured tire pressure on each vehicle coming into the gas station and 
compared the measured pressures to the vehicle's placard pressure. They 
found that about 36 percent of passenger cars and about 40 percent of 
light trucks had at least one tire that was at least 20 percent below 
the placard pressure.\18\ About 26 percent of passenger cars and 29 
percent of light trucks had at least one tire that was at least 25 
percent below the placard pressure. The agency notes those levels of 
under-inflation because they are the threshold levels for the low-tire 
pressure warning telltale illumination under the two alternatives the 
agency proposed in the NPRM for TPMSs. (66 FR 38982, July 26, 2001).
---------------------------------------------------------------------------

    \18\ For purposes of this discussion, the agency classified 
pick-up trucks, SUVs, and vans with either P-metric, LT, or 
flotation tires as light trucks.
---------------------------------------------------------------------------

D. Consequences of Under-Inflation of Tires

1. Reduced Vehicle Safety--Tire Failures and Increases in Stopping 
Distance
    When a tire is used while significantly under-inflated, its 
sidewalls flex more and the air temperature inside the tire increases, 
increasing stress and the risk of failure. In addition, a significantly 
under-inflated tire loses lateral traction,

[[Page 38714]]

making handling more difficult. Under-inflation also plays a role in 
crashes due to flat tires and blowouts. Finally, significantly under-
inflated tires can increase a vehicle's stopping distance.
    NHTSA's current crash files do not contain any direct evidence that 
points to low tire pressure as the cause of any particular crash.\19\ 
However, this lack of data does not imply that low tire pressure does 
not cause or contribute to any crashes. The agency believes that it 
simply reflects the fact that measurements of tire pressure are not 
among the vehicle information included in the crash reports received by 
the agency and placed in its crash data bases.\20\
---------------------------------------------------------------------------

    \19\ In response to the TREAD Act, NHTSA has added new tire 
related variables and attributes, including tire make, model, 
recommended tire pressure, actual tire pressure, and tread depth to 
its crash databases. These new variables will provide more specific 
tire data for vehicles involved in crashes.
    \20\ These crash databases are the NASS-CDS and the Fatality 
Analysis Reporting System (FARS).
---------------------------------------------------------------------------

    The only tire-related data element in the agency's crash databases 
is ``flat tire or blowout.'' However, even in crashes for which a flat 
tire or blowout is reported, crash investigators cannot tell whether 
low tire pressure contributed to the tire failure.
    The agency examined its crash files to gather information on tire-
related problems that resulted in crashes. The NASS-CDS has trained 
investigators who collect data on a sample of tow-away crashes around 
the United States. These data can be weighted to generate national 
estimates.
    The NASS-CDS General Vehicle Form contains a value indicating 
vehicle loss of control due to a blowout or flat tire. This value is 
used only when a vehicle's tire went flat, causing a loss of control of 
the vehicle and a crash. The value is not used for cases in which one 
or more of a vehicle's tires were under-inflated, preventing the 
vehicle from performing as well as it could have in an emergency 
situation.
    NHTSA examined NASS-CDS data for 1995 through 1998 and estimated 
that 23,464 tow-away crashes, or 0.5 percent of all crashes, are caused 
by blowouts or flat tires each year. The agency placed the tow-away 
crashes from the NASS-CDS files into two categories: passenger car 
crashes and light truck crashes. Passenger cars were involved in 10,170 
of the tow-away crashes caused by blowouts or flat tires, and light 
trucks were involved in the other 13,294.
    NHTSA also examined data from the Fatality Analysis Reporting 
System (FARS) for evidence of tire problems in fatal crashes. In FARS, 
if tire problems are noted after the crash, the simple fact of their 
existence is all that is noted. No attempt is made to ascribe a role in 
the crash to those problems. Thus, the agency does not know whether the 
noted tire problem caused the crash, influenced the severity of the 
crash, or simply occurred during the crash. For example, a tire may 
have blown out and caused the crash, or it may have blown out during 
the crash when the vehicle struck some object, such as a curb.
    Thus, while an indication of a tire problem in the FARS file gives 
some clue as to the potential magnitude of tire problems in fatal 
crashes, the FARS data cannot give a precise measure of the causal role 
played by those problems. The very existence of tire problems is 
sometimes difficult to detect and code accurately. Further, coding 
practices vary from State to State. Nevertheless, the agency notes 
that, from 1995 to 1998, 1.1 percent of all light vehicles involved in 
fatal crashes were coded as having tire problems. Over 535 fatal 
crashes involved vehicles coded with tire problems.
    Under-inflated tires can contribute to types of crashes other than 
those resulting from blowouts or tire failure, including crashes which 
result from: skidding and/or a loss of control of the vehicle in a 
curve or in a lane change maneuver; an increase in a vehicle's stopping 
distance; or hydroplaning on a wet surface.
    The 1977 Indiana Tri-level study associated low tire pressure with 
loss of control on both wet and dry pavements. The study never defined 
low tire pressure as a ``definite'' (i.e., 95 percent certainty that 
the crash would not have occurred absent this condition) cause of any 
crash, but did identify it as a ``probable'' (80 percent certainty that 
the crash would not have occurred absent this condition) cause of the 
crash in 1.4 percent of the 420 in-depth crash investigations.
    The study divided ``probable'' cause into two levels: a ``causal'' 
factor and a ``severity-increasing'' factor. A ``causal'' factor was 
defined as a factor whose absence would have prevented the accident 
from occurring. A ``severity-increasing'' factor was defined as a 
factor whose presence was not sufficient, by itself, to result in the 
occurrence of the accident, but which resulted in an increase in speed 
of the initial impact. The study determined that under-inflated tires 
were a causal factor in 1.2 percent of the probable cause cases and a 
severity-increasing factor in 0.2 percent of the probable cause cases.
    Note that more than one probable cause could be assigned to a 
crash. In fact, there were a total of 138.8 percent causes listed as 
probable causes (92.4 percent human factors, 33.8 percent environmental 
factors, and 12.6 percent vehicle factors). Thus, tire under-
inflation's part of the total is one percent (1.4/138.8). The agency 
focused solely on the probable cause cases, which represent 0.86 
percent of crashes (1.2/1.4 * 1.0).
    Tires are designed to maximize their performance capabilities at a 
specific inflation pressure. When a tire is under-inflated, the shape 
of its footprint and the pressure it exerts on the road surface are 
both altered, especially on wet surfaces. An under-inflated tire has a 
larger footprint than a properly inflated tire. Although the larger 
footprint results in an increase in rolling resistance on dry road 
surfaces due to increased friction between the tire and the road 
surface, it also reduces the tire load per unit area. On dry road 
surfaces, the countervailing effects of a larger footprint and reduced 
load per unit of area nearly offset each other, with the result that 
the vehicle's stopping distance performance is only mildly affected by 
under-inflation.
    On wet surfaces, however, under-inflation typically increases 
stopping distance for several reasons. First, as noted above, the 
larger tire footprint provides less tire load per area than a smaller 
footprint. Second, since the limits of adhesion are lower and achieved 
earlier on a wet surface than on a dry surface, a tire with a larger 
footprint, given the same load, is likely to slide earlier than the 
same tire with a smaller footprint because of the lower load per 
footprint area. The rolling resistance of an under-inflated tire on a 
wet surface is greater than the rolling resistance of the same tire 
properly-inflated on the same wet surface. This is because the slightly 
larger tire footprint on the under-inflated tire results in more rubber 
on the road and hence more friction to overcome. However, the rolling 
resistance of an under-inflated tire on a wet surface is less than the 
rolling resistance of the same under-inflated tire on a dry surface 
because of the reduced friction caused by the thin film of water 
between the tire and the road surface. The less tire load per area and 
lower limits of adhesion of an under-inflated tire on a wet surface are 
enough to overcome the increased friction caused by the larger 
footprint of the under-inflated tire. Hence, under-inflated tires cause 
longer stopping distance on wet surfaces than properly-inflated tires.

[[Page 38715]]

    The agency has received data from Goodyear indicating that 
significantly under-inflated tires increase a vehicle's stopping 
distance.\21\ The effects of tire under-inflation on vehicle stopping 
distance are discussed in greater detail in the agency's Final Economic 
Analysis (FEA).
---------------------------------------------------------------------------

    \21\ Goodyear submitted these data to the docket in a letter 
dated September 14, 2001. See Docket No. NHTSA-2000-8572-160. OMB 
criticized NHTSA's application of these data to certain vehicle 
types in estimating safety benefits for this rulemaking. The agency 
responds to that criticism below in section VI.F., ``Technical 
Foundation for NHTSA's Safety Benefit Analyses.'' The Alliance also 
questioned NHTSA's use of the Goodyear data. The agency explains its 
use of the Goodyear data below in footnotes 22 and 23, and in the 
agency's Final Economic Analysis (FEA).
---------------------------------------------------------------------------

    As explained in the FEA, the agency did not use the VRTC data or 
the Goodyear data that the agency used to estimate benefits in the NPRM 
because of concerns with the way in which the both tests were 
performed.\22\ The agency believes that the more recent Goodyear test 
methodology adequately addressed these concerns.\23\
---------------------------------------------------------------------------

    \22\ For example, the VRTC only tested new tires, not worn tires 
that are more typical of the tires on most vehicles. In addition, 
the NHTSA track surface is considered to be aggressive in that it 
allows for maximum friction with tire surfaces. It is more 
representative of a new road surface than the worn surfaces 
experienced by the vast majority of road traffic. The previous 
Goodyear tests on wet surfaces were conducted on surfaces with .05 
inch of standing water. This is more than would typically be 
encountered under normal wet road driving conditions. The agency 
expressed concerns with the adequacy of both sets of test data in a 
memo to the docket. (Docket No. NHTSA-2000-8572-81.)
    \23\ For example, in its more recent tests Goodyear tested tires 
with two tread depths: full tread, which is representative of new 
tires, and half tread, which is representative of worn tires. 
Goodyear also conducted wet surface tests on surfaces with .02 inch 
of standing water, which is more representative of typical wet road 
driving conditions.
---------------------------------------------------------------------------

2. Reduced Tread Life
    Unpublished data submitted to the agency by Goodyear indicate that 
when a tire is under-inflated, more pressure is placed on the shoulders 
of the tire, causing the tread to wear incorrectly.\24\ The Goodyear 
data also indicate that the tread on an under-inflated tire wears more 
rapidly than it would if the tire were inflated to the proper pressure.
---------------------------------------------------------------------------

    \24\ Docket No. NHTSA-2000-8572-26.
---------------------------------------------------------------------------

    The Goodyear data indicate that the average tread life of a tire is 
45,000 miles, and the average cost of a tire is $61 (in 2000 dollars). 
Goodyear also estimated that a tire's average tread life would drop to 
68 percent of the expected tread life if tire pressure dropped from 35 
psi to 17 psi and remained there. Goodyear assumed that this 
relationship was linear. Thus, for every 1-psi drop in tire pressure, 
tread life would decrease by 1.78 percent (32 percent/18 psi). This 
loss of tread life would take place over the lifetime of the tire. 
Thus, according to Goodyear's data, if the tire remained under-inflated 
by 1 psi over its lifetime, its tread life would decrease by about 800 
miles (1.78 percent of 45,000 miles).
    As noted above, data from the NCSA tire pressure survey indicate 
that 26 percent of passenger cars had at least one tire that was under-
inflated by at least 25 percent. The average level of under-inflation 
of the four tires on passenger cars with at least one tire under-
inflated by at least 25 percent was 6.8 psi. Thus, on average, these 
passenger cars could lose about 5,440 miles (6.8 psi under-inflation x 
800 miles) of tread life due to under-inflation, if their tires were 
under-inflated to that extent throughout the life of the tires.
    Also as noted above, data from the NCSA tire pressure survey 
indicate that about 29 percent of light trucks had at least one tire 
that was under-inflated by at least 25 percent. The average level of 
under-inflation of the four tires on light trucks with at least one 
tire under-inflated by at least 25 percent was 8.7 psi. Thus, on 
average, these light trucks could lose about 6,960 miles (8.7 psi 
under-inflation x 800 miles) of tread life due to under-inflation, if 
their tires were under-inflated to that extent throughout the life of 
the tires.
3. Reduced Fuel Economy
    Under-inflation increases the rolling resistance of a vehicle's 
tires and, correspondingly, decreases the vehicle's fuel economy. 
According to a 1978 report, fuel efficiency is reduced by one percent 
for every 3.3 psi of under-inflation.\25\ More recent data provided by 
Goodyear indicate that fuel efficiency is reduced by one percent for 
every 2.96 psi of under-inflation.\26\
---------------------------------------------------------------------------

    \25\ The Aerospace Corporation, Evaluation of Techniques for 
Reducing In-use Automotive Fuel Consumption, June 1978.
    \26\ Docket No. NHTSA-2000-8572-26.
---------------------------------------------------------------------------

    NHTSA notes that there is an apparent conflict between these data, 
which indicate that under-inflation increases rolling resistance and 
thus decreases fuel economy and the previously mentioned Goodyear data 
that indicates under-inflated tires increase a vehicle's stopping 
distance. While an under-inflated tire typically has a larger tread 
surface area (i.e., tire footprint) in contact with the road, which 
might be thought to improve its traction during braking, the larger 
tire footprint also reduces the tire load per unit area. The larger 
footprint does result in an increase in rolling resistance on dry road 
surfaces due to increased friction between the tire and the road 
surface. On dry road surfaces, though, the countervailing effects of a 
larger footprint and reduced load per unit of area nearly offset each 
other, with the result that the vehicle's stopping distance performance 
is only mildly affected by under-inflation on those surfaces. However, 
as explained above in section III.D.1., ``Reduced Vehicle Safety--Tire 
Failures and Increases in Stopping Distance,'' on wet surfaces other 
attributes of under-inflation lead to increased stopping distances.

IV. Tire Pressure Monitoring Systems

    There are currently two types of TPMSs: direct and indirect. Other 
types, including hybrid TPMSs that combine aspects of both direct and 
indirect systems, may be developed in the future. Direct TPMSs directly 
measure the pressure in a vehicle's tires, while indirect TPMSs 
estimate differences in pressure by comparing the rotational speed of 
the wheels. To varying degrees, both types can inform the driver when 
the pressure in one or more tires falls below a pre-determined level. 
Unless the TPMS is connected to an automatic inflation system, the 
driver must stop the vehicle and inflate the under-inflated tire(s), 
preferably to the pressure recommended by the vehicle manufacturer. 
Currently, TPMSs are available as original equipment on a few vehicle 
models. They are available also as after-market equipment, but few are 
sold. At this time, NHTSA does not have any information indicating that 
a hybrid TPMS is being planned for production. However, the agency 
received comments from TRW, a TPMS manufacturer, stating its belief 
that such a system could be produced.
    The VRTC evaluated six direct and four indirect TPMSs that are 
currently available.\27\ The VRTC found that the direct TPMSs were 
accurate to within an average of 1.0 psi.\28\ This leads 
the agency to believe that those current TPMSs are more accurate than 
the systems that were available at the time of the agency s 1981 
rulemaking on TPMSs.
---------------------------------------------------------------------------

    \27\ An Evaluation of Existing Tire Pressure Monitoring Systems, 
May 2001. A copy of this report is available in the docket. (Docket 
No. NHTSA-2000-8572-29.)
    \28\ This is not to say that the systems were able to detect a 
1.0 psi drop in pressure. The systems were accurate within 
1.0 psi once tire pressure had fallen by a certain 
percentage.
---------------------------------------------------------------------------

    Following is a description of the two currently available types of 
TPMSs and their capabilities.

[[Page 38716]]

A. Indirect TPMSs

    Current indirect TPMSs work with a vehicle's ABS. The ABS employs 
wheel speed sensors to measure the rotational speed of each of the four 
wheels. As a tire's pressure decreases, the rolling radius decreases, 
and the rotational speed of that wheel increases correspondingly. Most 
current indirect TPMSs compare the sums of the wheel speeds on each 
diagonal (i.e., the sum of the speeds of the right front and left rear 
wheels as compared to the sum of the speeds of the left front and right 
rear wheels). Dividing the difference of the sums by the average of the 
four wheels speeds allows the indirect TPMS to have a ratio that is 
independent of vehicle speed. This ratio is best expressed by the 
following equation: [(RF + LR) - (LF + RR)/Average Speed]. If this 
ratio deviates from a set tolerance, one or more tires must be over- or 
under-inflated. A telltale then indicates to the driver that a tire is 
under-inflated. However, the telltale cannot identify which tire is 
under-inflated. Current vehicles that have indirect TPMSs include the 
Toyota Sienna, Ford Windstar, and Oldsmobile Alero.
    Current indirect TPMSs must compare the average of the speeds of 
the diagonal wheels for several reasons. First, current indirect TPMSs 
cannot compare the speed of one wheel to the speeds of the other three 
wheels individually or to the average speed of the four wheels. During 
any degree of turning, the outside tires must rotate faster than the 
inside tires. Thus, all four wheel speeds deviate significantly when 
the vehicle is in a curve or turn. If a current indirect TPMS compared 
each individual wheel speed to the average of all four wheels speeds, 
the system would provide a false alarm each time the vehicle rounded a 
curve or made a turn. The same would be true if the indirect TPMS 
compared each individual wheel speed to the speed of the other three 
wheels individually. Since the outside wheels would rotate much faster 
than the inside wheels in a curve or turn, each outside tire would 
appear to be under-inflated when compared to an inside tire.
    Current indirect TPMSs also cannot compare the speeds of the front 
wheels to the speeds of the rear wheels because in curves, the front 
and rear wheels (on both sides of the vehicle) rotate at different 
speeds. This is primarily due to the fact that the front axle is 
steerable and follows a different trajectory than the rear axle. As a 
result, current indirect TPMS must compare a tire from each side and a 
tire from the front and rear axles to factor out the speed difference 
caused by curves and turns. Thus, current indirect TPMSs must compare 
the average speed of the diagonal wheels.
    The VRTC tested four current ABS-based indirect TPMSs. None met all 
the requirements of either alternative proposed in the NPRM. All but 
one did not illuminate the low tire pressure warning telltale when the 
pressure in the vehicle's tires decreased to 20 or 25 percent below the 
placard pressure.\29\ The VRTC determined that since reductions in tire 
diameter with reductions in pressure are very slight in the 15-40 psi 
range, most current indirect TPMSs require a 20 to 30 percent drop in 
pressure before they are able to detect under-inflation. The VRTC also 
concluded that those thresholds were highly dependent on tire and 
loading factors.
---------------------------------------------------------------------------

    \29\ The Continental Teves indirect TPMS on the BMW M3 activated 
the warning telltale at pressures between 9 and 21 percent below the 
placard pressure.
---------------------------------------------------------------------------

    The VRTC also found that none of the tested indirect TPMSs were 
able to detect significant under-inflation when all four of the 
vehicle's tires were equally under-inflated, or when two tires on the 
same axle or two tires on the same side of the vehicle were equally 
under-inflated. However, the VRTC did find that indirect TPMSs could 
detect when two tires located diagonally from each other (e.g., the 
front left and back right tires) became significantly under-inflated.

B. Direct TPMSs

    Direct TPMSs use pressure sensors, located in each wheel, to 
directly measure the pressure in each tire. These sensors broadcast 
pressure data via a wireless radio frequency transmitter to a central 
receiver. The data are then analyzed and the results sent to a display 
mounted inside the vehicle. The type of display varies from a simple 
telltale, which is how most vehicles are currently equipped, to a 
display showing the pressure in each tire, sometimes including the 
spare tire. Thus, direct TPMSs can be linked to a display that tells 
the driver which tire is under-inflated. An example of a vehicle 
equipped with a direct system is the Chevrolet Corvette.
    Since direct TPMSs actually measure the pressure in each tire, they 
are able to detect when any tire or when each tire in any combination 
of tires is under-inflated, including when all four of the vehicle's 
tires are equally under-inflated. Direct TPMSs also can detect small 
pressure losses. Some systems can detect a drop in pressure as small as 
1 psi.

C. Hybrid TPMSs

    In their comments on the NPRM, TRW, a manufacturer of both direct 
and indirect TPMSs, stated that in order to meet the proposed 
requirements of the 3-tire, 25 percent alternative, current indirect 
TPMSs would need the equivalent of the addition of two tire pressure 
sensors and a radio frequency receiver. The tire pressure sensors would 
be installed on wheels located diagonally from each other.
    For the following reasons, the agency believes that such a 
``hybrid'' TPMS would be able to overcome the limitations of current 
indirect TPMSs, i.e., the inability to detect when all four tires, or 
two tires on the same axle or same side of the vehicle are under-
inflated. First, a hybrid TPMS would be able to detect when two tires 
on the same axle or the same side of the vehicle were under-inflated 
because one of those tires necessarily would contain a direct pressure 
sensor. Second, a hybrid TPMS would be able to detect when the two 
tires without a direct pressure sensor were under-inflated because they 
would be located diagonally from each other, and, as the VRTC found in 
its review of current TPMSs, current indirect TPMSs are able to detect 
when two tires located diagonally from each other are under-inflated. 
Third, a hybrid TPMS would be able to detect when three or four tires 
were under-inflated because one of those tires necessarily would 
contain a direct pressure sensor.
    However, since the agency does not have any information indicating 
that a hybrid TPMS is currently being planned for production, the 
agency does not know when such a system could be produced.

V. Summary of Preliminary Determination About the Final Rule

    In this section, NHTSA summarizes its preliminary determination 
about the final rule that was submitted to OMB in December 2001.

A. Alternative Long-Term Requirements Analyzed in Making Preliminary 
Determination

    For purposes of the preliminary determination, the agency analyzed 
three alternatives. The first alternative (four tires, 20 percent) 
would have required a vehicle's TPMS to warn the driver when the 
pressure in any single tire or in each tire in any combination of 
tires, up to a total of four tires, fell to 20 percent or more below 
the placard pressure, or a minimum level of pressure specified in the 
standard, whichever pressure was higher. The

[[Page 38717]]

second alternative (three tires, 25 percent) would have required a 
vehicle's TPMS to warn the driver when the pressure in any single tire 
or in each tire in any combination of tires, up to a total of three 
tires, fell to 25 percent or more below the placard pressure, or a 
minimum level of pressure specified in the standard, whichever pressure 
was higher. The third alternative (four tires, 25 percent) combined 
aspects of the first two alternatives. It would have required a 
vehicle's TPMS to warn the driver when the pressure in any single tire 
or in each tire in any combination of tires, up to a total of four 
tires, fell to 25 percent or more below the placard pressure, or a 
minimum level of pressure specified in the standard, whichever pressure 
was higher. The minimum levels of pressure specified in the standard 
would have been the same for all three alternatives.
    The agency estimated that the four-tire, 20 percent alternative 
would have prevented from 141 to 145 fatalities and prevented or 
reduced in severity from 10,271 to 10,611 injuries per year.\30\ The 
agency estimated that the average net cost of this alternative would 
have been from $76.77 to $77.53 per vehicle.\31\ Since approximately 16 
million vehicles are produced for sale in the United States each year, 
the total annual net cost of this alternative would have been from 
$1.228 billion to $1.241 billion. The net cost per equivalent life 
saved would have been from $5.1 million to $5.3 million.
---------------------------------------------------------------------------

    \30\ NHTSA assumed that drivers would respond differently to 
different information displays. To get the upper bound, the agency 
assumed that manufacturers that installed direct TPMSs would also 
install a display showing the pressure of each tire. Currently only 
direct TPMSs are capable of displaying individual tire pressure. The 
agency also assumed that 33 percent of drivers would respond to such 
a display by re-inflating their tires when they became under-
inflated by 10 percent, and that the other 67 percent would respond 
by re-inflating their tires when they became under-inflated by 20 
percent, i.e., when the warning telltale would have been activated. 
To get the lower bound, the agency assumed that manufacturers would 
install only a low tire pressure warning telltale, as would have 
been required. Thus, all drivers would not re-inflate their tires 
until they became under-inflated by 20 percent, and the warning 
telltale was activated.
    \31\ The net cost is the vehicle cost plus the maintenance cost 
minus the fuel and tread wear savings. The difference in costs is 
due to the cost of adding an individual tire pressure display. The 
agency assumed that manufacturers would install direct TPMSs on 
vehicles that are not equipped with ABS because the cost of adding a 
direct TPMS was significantly less than the cost of adding ABS and 
an indirect TPMS.
---------------------------------------------------------------------------

    The agency estimated that the three-tire, 25 percent alternative 
would have prevented 110 fatalities and prevented or reduced in 
severity 7,526 injuries per year. The agency estimated that the average 
net cost would have been $63.64 per vehicle, and the total annual net 
cost would have been $1.018 billion. The net cost per equivalent life 
saved would have been $5.8 million.
    The agency estimated that the four-tire, 25 percent alternative 
would have prevented 124 fatalities and prevented or reduced in 
severity 8,722 injuries per year. The agency estimated that the average 
net cost would have been $53.87 per vehicle, and the total annual net 
cost would have been $862 million. The net cost per equivalent life 
saved would have been $4.3 million.
    The agency noted that the vehicle costs of these alternatives could 
be reduced in the future as manufacturers learned how to produce TPMSs 
more efficiently. Moreover, maintenance costs could be significantly 
reduced in the future if manufacturers could mass produce a direct TPMS 
that did not require the pressure sensors to be replaced when the 
batteries are depleted.\32\
---------------------------------------------------------------------------

    \32\ One TPMS manufacturer, IQ-mobil Electronics of Germany, 
indicated in its comments that it has developed a pressure sensor 
that does not require a battery.
---------------------------------------------------------------------------

    NHTSA considered these three alternatives because the agency 
believed that TPMSs that complied with these alternatives would warn 
drivers of significantly under-inflated tires in a wide variety of 
reasonably foreseeable circumstances, including when more than one tire 
was significantly under-inflated. The agency also believed that 
improved indirect TPMSs could be developed to meet the requirements of 
the three-tire, 25 percent alternative and hybrid TPMSs could be 
developed to meet the three-tire, 25 percent and four-tire, 25 percent 
alternatives. Thus, the agency believed that these alternatives would 
provide an effective warning while striking a reasonable balance 
between encouraging further improvements in TPMS technology and 
stringency of the performance requirements and striking a reasonable 
balance between safety benefits and costs.

B. Phase-In and Long-Term Requirements

    To facilitate compliance, the preliminary determination specified a 
four-year phase-in schedule,\33\ During the phase-in, i.e., between 
November 1, 2003 and October 31, 2006, it would have allowed compliance 
with either of two options: a four-tire, 25 percent option or a one-
tire, 30 percent option. Under the first option, a vehicle's TPMS would 
have had to warn the driver when the pressure in one or more of the 
vehicle's tires, up to a total of four tires, was 25 percent or more 
below the placard pressure, or a minimum level of pressure specified in 
the standard, whichever pressure was higher. Under the second option, a 
vehicle's TPMS would have had to warn the driver when the pressure in 
any one of the vehicle's tires was 30 percent or more below the placard 
pressure, or a minimum level of pressure specified in the standard, 
whichever pressure was higher. The minimum levels of pressure specified 
in the standard were the same for both compliance options.
---------------------------------------------------------------------------

    \33\ The phase-in schedule was as follows: 10 percent of a 
manufacturer's affected vehicles would have had to comply with 
either compliance option in the first year; 35 percent in the second 
year; and 65 percent in the third year. In the fourth year, 100 
percent of a manufacturer's affected vehicles would have had to 
comply with the long-term requirements, i.e., the four-tire, 25 
percent compliance option.
---------------------------------------------------------------------------

    Under both options, the preliminary determination would have 
required the low tire pressure warning telltale to remain illuminated 
as long as any one of the vehicle's tires remained significantly under-
inflated, and the key locking system was in the ``On'' (``Run'') 
position. The telltale could have been deactivated automatically only 
when all of the vehicle's tires ceased to be significantly under-
inflated, or manually in accordance with the vehicle manufacturer's 
instructions.
    The preliminary determination would have required each TPMS to be 
compatible with all replacement or optional tires (but not rims) of the 
size(s) recommended for use on the vehicle by the vehicle manufacturer. 
It would also have required that the telltale perform a bulb-check at 
vehicle start-up. It specified written instructions 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 was illuminated, and what actions drivers should take 
when the telltale is illuminated, to be placed in the vehicle's owner's 
manual.
    The preliminary determination would not have required TPMSs to 
monitor the spare tire, either when the tire was stowed or when it was 
installed on the vehicle. It also would not have required the TPMS to 
indicate a system malfunction.
    The agency created the one-tire, 30 percent option so that vehicle 
manufacturers could continue to install current indirect TPMSs for 
several more years, thus providing additional time and flexibility for 
innovation and technological development. The agency created the other 
option by adjusting the definition of ``significantly under-inflated'' 
for the four-tire option to 25 percent (instead of 20 percent) so that

[[Page 38718]]

improved indirect TPMSs and hybrid TPMSs could be used to comply with 
the TPMS standard. After the phase-in, i.e., after October 31, 2006, 
the second option would have been terminated, and the provisions of the 
first option would have become mandatory for all new vehicles.
    The agency tentatively believed that a four-tire, 25 percent 
requirement was preferable for the long-term because it would require 
TPMSs that warn drivers about all combinations of significantly under-
inflated tires and provide more timely and effective warnings. The 
agency tentatively believed that a one-tire, 30 percent requirement 
would allow TPMSs that do not warn about all combinations of 
significantly under-inflated tires and do not provide warnings until 
the extent of under-inflation reaches 30 percent below the placard 
pressure. Thus, it appeared that a four-tire, 25 percent requirement 
would better fulfill the purposes of the TPMS mandate in the TREAD Act, 
while encouraging further improvements in TPMS technology.

VI. Response to Issues Raised in OMB Return Letter About 
Preliminary Determination

    Pursuant to section 6(a)(3) of Executive Order 12866, NHTSA is 
required to provide a written response to the points made by OMB in its 
February 12 return letter. As noted above, OMB stated in its return 
letter that: NHTSA should base its decision about the final rule on 
overall safety, instead of tire safety; while direct TPMSs can detect 
under-inflation under a greater variety of circumstances than indirect 
TPMSs, the indirect system captures a substantial portion of the 
benefit provided by direct systems; NHTSA should consider a fourth 
alternative for the long-term requirement, a one-tire, 30 percent 
compliance option, indefinitely, since it would allow vehicle 
manufacturers to install current indirect TPMSs; NHTSA, in analyzing 
long-term alternatives, should consider both their impact on the 
availability of ABS as well as the potential safety benefits of ABS; 
and that NHTSA should provide a better explanation of the technical 
foundation for the agency's safety benefits estimates and subject those 
estimates to sensitivity analyses.

A. Criteria for Selecting the Long-Term Requirement

1. Tire Safety and Overall Vehicle Safety
    OMB stated in its return letter that ``a rule permitting indirect 
systems may provide more overall safety than a rule that permits only 
direct or hybrid systems.'' OMB said:

    Although direct systems are capable of detecting low pressure 
under a greater variety of circumstances than indirect systems, the 
indirect system captures a substantial portion of the benefit 
provided by direct systems. Moreover, allowing indirect systems will 
reduce the incremental cost of equipping vehicles with anti-lock 
brakes, thereby accelerating the rate of adoption of ABS technology 
* * *. Both experimental evidence and recent real-world data have 
indicated a modest net safety benefit from anti-lock brakes.

    While NHTSA's general obligation under the Vehicle Safety Act is to 
improve overall vehicle safety, it is mindful that its specific, 
immediate obligation in this rulemaking is to comply with the mandate 
of section 13 of the TREAD Act. The agency is seeking to comply with 
the mandate and safety goals of the TREAD Act in a way that encourages 
innovation and allows a range of technologies to the extent consistent 
with providing drivers with sufficient warning of low tire pressure 
under a broad variety of the reasonably foreseeable circumstances in 
which tires become under-inflated.
2. Statutory Mandate
    Section 13 of the TREAD Act mandated the completion of ``a 
rulemaking for a regulation to require a warning system in new motor 
vehicles to indicate to the operator when a tire is significantly under 
inflated'' within one year of the TREAD Act's enactment. As noted 
below, the agency tentatively believes, based on the current record, 
that a four-tire, 25 percent under-inflation requirement would best 
meet the mandate.

B. Relative Ability of Direct and Current Indirect TPMSs To Detect 
Under-Inflation

    As noted above, current indirect TPMSs work, in part, by adding the 
speeds of diagonal sets of tires and subtracting the sum of one set 
from the sum of the other. As a result, if all four tires are 
significantly under-inflated, and the difference in the tire pressures 
is not 30 percent or greater, current indirect TPMSs will not provide a 
warning. Similarly, if two tires on the same axle or same side of the 
vehicle are significantly under-inflated, current indirect TPMSs will 
not provide a warning.
    These combinations of significantly under-inflated tires occur 
frequently enough that current indirect TPMSs would have provided a 
warning in only about 50 percent of the instances in which NHTSA found 
significant under-inflation in the February 2001 NCSA survey. 
Conversely, current direct TPMSs would have provided warnings in all 
those instances.
    The following figures indicate how often current direct and 
indirect TPMSs would provide warnings when a vehicle has at least one 
tire that is at least 30 percent below the placard pressure.
    Of the 5,967 passenger cars in the February 2001 NCSA survey, 1,199 
(20 percent) had at least one tire that was at least 30 percent below 
the placard pressure. Current direct TPMSs would have provided a 
warning in every case, while current indirect TPMSs would have provided 
a warning in only 653 cases (54 percent).
    Of the 3,950 light trucks in the NCSA survey, 789 (20 percent) had 
at least one tire that was at least 30 percent below the placard 
pressure. Current direct TPMSs would have provided a warning in every 
case, while current indirect TPMSs would have provided a warning in 
only 359 cases (46 percent).
    Thus, of the total 9,917 passenger cars and light trucks in the 
NCSA survey, 1,988 (20 percent) had at least one tire that was at least 
30 percent below the placard pressure. Current direct TPMSs would have 
provided a warning in every case, while current indirect TPMSs would 
have provided a warning in only 1,012 cases (51 percent).
    Current indirect TPMSs would have failed to provide a warning in 
the remainder of the cases for various reasons. Many of the vehicles 
had one tire that was 30 percent below the placard pressure, but not 30 
percent below the pressure in the other tires. As noted above, current 
indirect TPMSs require at least a 30 percent differential in tire 
pressure before providing a warning. Other vehicles had more than one 
tire that was 30 percent below the placard pressure. As noted above, 
current indirect TPMSs cannot detect when all four of a vehicle's 
tires, or two tires on the same side of the vehicle or the same axle, 
are under-inflated.
    The absence of a warning in approximately 50 percent of the 
instances of significant under-inflation is a matter of concern given 
that many drivers will rely on a TPMS instead of regularly checking 
their tire pressure. Data from the July 2001 BTS omnibus survey 
indicate that 65 percent of people would be less concerned, to either a 
great extent or a very great extent, with routinely maintaining the 
pressure of their tires if their vehicle were equipped with a TPMS.\34\
---------------------------------------------------------------------------

    \34\ NHTSA notes that in its prepared statement submitted in 
connection with the February 28, 2002 hearing before the House 
Committee on Energy and Commerce on the TREAD Act, OMB stated: The 
1-tire standard will provide warnings when 1 tire is underinflated 
but will not necessarily detect situations when 2 or more tires are 
underinflated. A further weakness of the 1-tire standard is that 
consumers may misperceive that their tires are fine (since the 
warning light is off) when in fact all four of their tires are 
equally underinflated. The 4-tire standard overcomes these problems.

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

[[Page 38719]]

C. Analysis of a Fourth Alternative Long-Term Requirement: One-Tire, 30 
Percent Under-Inflation Detection

    As explained above in section V.A., ``Alternative Long-Term 
Requirements Analyzed in Making Preliminary Determination,'' NHTSA 
analyzed three alternatives: a four-tire, 20 percent alternative; a 
three-tire, 25 percent alternative and a four-tire, 25 percent 
alternative.
    OMB recommended that the agency analyze a fourth alternative that 
would require a vehicle's TPMS to warn the driver when the pressure in 
any one of the vehicle's tires is 30 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. (This alternative is referred to below as the ``one-tire, 30 
percent alternative.'') The agency's analysis of the benefits and costs 
of this alternative follows.
    The agency estimates that the one-tire, 30 percent alternative 
would prevent 79 fatalities and prevent or reduce in severity 5,176 
injuries. The agency estimates that the average per vehicle cost of 
this alternative would be $33.34. Since approximately 16 million light 
vehicles are produced for sale in the United States each year, the 
total annual cost of this alternative would be $533 million. The agency 
estimates that the average per vehicle maintenance cost would be 
$13.50,\35\ and that the average per vehicle fuel and tread life 
savings over the lifetime of the vehicle would be $2.06 and $0.65, 
respectively. Thus, the net per vehicle cost of this alternative would 
be $44.13, and the total annual net cost would be $706 million. The net 
cost per equivalent life saved would be $5.8 million.
---------------------------------------------------------------------------

    \35\ If the one-tire, 30 percent alternative were the only 
alternative available to vehicle manufacturers, the agency 
anticipates that the approximately \1/3\ of vehicles not equipped 
with ABS would nevertheless comply by means of direct TPMSs. The 
approximately $40.91 of maintenance costs for each of those 
vehicles, if averaged over the entire fleet, is approximately 
$13.50.
---------------------------------------------------------------------------

D. Impact of One-Tire, 30 Percent Alternative on Installation Rate of 
ABS

    OMB said that NHTSA should analyze the impact of adopting its long-
term regulatory alternatives as well as an additional long-term 
alternative, a one-tire, 30 percent alternative, on the installation 
rate of ABS. Since the additional alternative is the only one that 
would permit compliance by means of installing current indirect TPMSs, 
and since OMB's suggestion that a TPMS standard could induce increased 
installation of ABS is dependent upon the manufacturers' being able to 
install that type of TPMS, NHTSA's analysis focuses on that 
alternative.
    The agency believes there is no reliable basis for concluding that 
permitting current indirect TPMSs to comply would lead to a significant 
increase in installation of ABS in light vehicles for the following 
reasons.
    First, the final rule does not mandate the installation of ABS. 
Vehicle manufacturers always have the option of providing a measure 
that exceeds NHTSA's standards. However, nothing in the final rule 
requires manufacturers to install ABS.
    Second, the rulemaking record does not contain a reliable basis for 
concluding that manufacturers will voluntarily install ABS in 
significantly more light vehicles in response to being permitted to 
install current indirect TPMSs. When the Alliance addressed the issue 
of increased voluntary installation of ABS in its September 6, 2001 
comments, it said only that a manufacturer ``may well'' opt to make ABS 
standard equipment on models for which optional ABS is currently 
available and is currently in high market demand. Further, only one 
manufacturer, Toyota, indicated that it might make ABS standard 
equipment on more vehicles if indirect TPMSs were allowed. Toyota 
provided this indication not in its written comments, but orally in a 
meeting with the agency. Nothing requires Toyota to make ABS standard 
equipment.
    Third, several manufacturers orally indicated that they would not 
install ABS on their light trucks even if indirect TPMSs were allowed. 
General Motors (GM) and Ford told NHTSA that they would install a 
direct TPMS on their trucks, rather than a four-channel ABS and 
indirect TPMS, because ABS was significantly more expensive. Further, 
the agency notes that in April 2002, GM announced that it would cease 
offering ABS as standard equipment on a number of its less expensive 
models of cars to make those models more price competitive.
    Fourth, it is not economically reasonable for manufacturers to 
install ABS voluntarily on significantly more vehicles in response to 
being permitted to install current indirect TPMSs. In the absence of 
written comments from individual manufacturers indicating that they are 
very likely to increase voluntarily their installation of ABS if 
allowed to install current indirect TPMSs, NHTSA may not simply assume 
that manufacturers will elect to spend $240 per vehicle to install ABS 
to save $53, the difference between the cost of a direct TPMS ($66) and 
an indirect TPMS ($13). The market for ABS has been static for several 
years, with the installation rate at about 63 percent. Absent a market 
demand for more installations, a manufacturer would not gain a market 
advantage by increasing the percentage of its vehicles with ABS.
    In NHTSA's Final Economic Assessment (FEA), the agency states that 
although a manufacturer may elect to increase the installation of ABS, 
it is solely a marketing decision.\36\ The influence, if any, this 
rulemaking might have on their marketing decisions is purely 
speculative. There are many factors that influence a manufacturer's 
decision to install equipment. Cost impact is only one of them.
---------------------------------------------------------------------------

    \36\ A copy of the FEA has been placed in the docket.
---------------------------------------------------------------------------

E. Overall Safety Effects of ABS

    In addition to recommending that the agency assume that the 
adoption of the one-tire, 30 percent compliance option would induce 
vehicle manufacturers to increase their installation of ABS, OMB also 
recommended that the agency take into account the potential safety 
benefits of ABS when estimating the benefits of that option. OMB 
suggested that ABS could reduce fatalities in light vehicles.
    NHTSA has analyzed ABS and has determined that there is currently 
no statistically reliable basis for concluding that ABS reduces 
fatalities in light vehicles for the following reasons.
    First, NHTSA has analyzed the impacts of ABS on light vehicle 
fatalities for the past decade, with mixed findings.\37\ In general, 
test track results indicate that ABS is a very promising technology 
that enables drivers to keep vehicles under control under adverse road 
conditions. Under some pavement conditions, ABS allows the driver to 
stop a vehicle more rapidly while maintaining steering control, even 
during panic braking.
---------------------------------------------------------------------------

    \37\ See ``Preliminary Evaluation of the Effectiveness of 
Antilock Brake Systems for Passenger Cars,'' NHTSA, December 1994, 
DOT HS 808 206. This study is available from the National Technical 
Information Service (NTIS) or NHTSA's Technical Reference Library.
---------------------------------------------------------------------------

    However, the agency's analysis of real world crash data shows that, 
on balance, ABS has not been proven, thus far, to be greatly beneficial 
in real world fatal crashes.
    NHTSA explored the desirability of requiring ABS on light vehicles 
in an

[[Page 38720]]

ANPRM issued in 1994 (59 FR 281; January 4, 1994) in response to the 
National Highway Traffic Safety Administration Authorization Act of 
1991. (Public Law 102-240, December 18, 1991). The Act directed the 
agency to consider the need for any additional brake performance 
standards for passenger cars, including ABS standards. The ANPRM 
solicited comments about whether rulemaking was warranted to require 
that all light vehicles be equipped with ABS. It also posed a number of 
questions relative to the regulatory approaches that might be employed 
if requirements were imposed; the types of performance tests that might 
be used; varieties of ABSs that might be appropriate; and regulatory 
implementation strategies and schedules that might be employed if 
requirements were established.
    Two years later, the agency issued a notice announcing that it had 
decided to defer indefinitely a decision whether to require equipping 
light vehicles with ABS. (61 FR 36698; July 12, 1996) In that notice, 
the agency stated that it was currently ``inappropriate'' to mandate 
ABS for the following reasons:

    (1) Most studies that have analyzed the accident involvement 
experiences of ABS-equipped light vehicles have found mixed 
patterns, with a reduction in accidents in some crash modes but an 
increase in accidents in other crash modes, (2) even without a 
Federal requirement, a significant majority of light vehicles will 
be voluntarily equipped with ABS, (3) and requiring ABS on those 
light vehicles that will not be equipped with ABS would result in 
significant costs that, on balance, cannot be justified at this 
time.

    In the 1996 notice, the agency lowered the prediction that it had 
made in its 1994 ANPRM that the rate of voluntary ABS installation in 
passenger cars would increase from 55 percent in 1994 to 85 percent in 
1999. Given that there had been almost no increase in the rate between 
the 1994 model year and 1995 model year, the agency suggested in the 
1996 notice that the rate in 1999 could be as low as 70 percent. Even 
that reduced figure has been shown by subsequent events to be overly 
optimistic. In 2000, the rate had reached only 63 percent for passenger 
cars.
    The agency noted in the 1996 notice that the costs of bringing the 
percentages up to 100 percent for both passenger cars and light trucks 
could be very high, over $1.5 billion annually.
    Since the 1996 notice, NHTSA has conducted additional studies. In 
one study, NHTSA measured the braking performance of a group of ABS-
equipped production vehicles over a broad range of maneuvers on 
different road surfaces. Results of this study showed that for most 
maneuvers, ABS-assisted stops yielded shorter stopping distances in 
comparison to non-ABS vehicles.\38\
---------------------------------------------------------------------------

    \38\ ``NHTSA Light Vehicle Antilock Brake System Research 
Program Task 4: A Test Track Study of Light Vehicle ABS Performance 
Over a Broad Range of Surfaces and Maneuvers,'' January 1999, DOT HS 
808 875, available at http://www-nrd.nhtsa.dot.gov/vrtc/ca/capubs/NHTSAabsT4FinalRpt.pdf.
---------------------------------------------------------------------------

    NHTSA has conducted several studies to examine possible reasons for 
the absence of overall safety benefits. One possible reason is that 
drivers are not adequately familiar or have inadequate or incorrect 
knowledge on the use of ABS. The agency has examined this possibility 
by conducting a national telephone survey to assess drivers' knowledge 
of ABS, its functionality and their expectations of its effects on 
vehicle performance. The results showed that, although most drivers had 
heard of ABS, many did not know what it did or how it affected vehicle 
performance.\39\
---------------------------------------------------------------------------

    \39\ ``NHTSA Light Vehicle Antilock Brake System Research 
Program Task 2: National Telephone Survey of Driver Experiences and 
Expectations Regarding Conventional Brakes versus ABS,'' November 
2001, DOT HS 809 429, available at http://www-nrd.nhtsa.dot.gov/vrtc/ca/capubs/abssurvey_rptfinal.pdf.
---------------------------------------------------------------------------

    The agency also investigated whether the apparent increase in 
single vehicle crashes was due to driver ``oversteering'' in crash-
imminent situations. The steering capability could have contributed to 
vehicles going off of the roadway during crash avoidance maneuvers. 
However, this steering activity was not found to result in a 
significant number of road departure crashes in NHTSA's research.\40\
---------------------------------------------------------------------------

    \40\ ``Driver Crash Avoidance Behavior with ABS in an 
Intersection Incursion Scenario on Dry Versus Wet Pavement,'' (SAE 
Paper No. 1999-01-1288), available at http://www-nrd.nhtsa.dot.gov/vrtc/ca/lvabs.htm.
---------------------------------------------------------------------------

    The agency also evaluated possible ABS-related behavioral 
adaptation of drivers through the collection of more detailed data 
about the driving behavior of subjects in a naturalistic research 
setting. This study did not indicate any statistically significant 
trend towards behavioral adaptation by drivers of ABS equipped vehicles 
in comparison to others.\41\
---------------------------------------------------------------------------

    \41\ ``NHTSA Light Vehicle Antilock Brake System Research 
Program Task 7.1: Examination of ABS-Related Driver Behavioral 
Adaptation--License Plate Study,'' November 2001, DOT HS 809 430, 
available at http://www-nrd.nhtsa.dot.gov/vrtc/ca/capubs/abs71.pdf.
---------------------------------------------------------------------------

    It is clear from the above comprehensive agency research efforts 
during the past five years that the agency still cannot explain why ABS 
systems do not produce the benefits anticipated from test track 
performance. Similarly, research by others has not yet succeeded in 
providing an explanation. Efforts by NHTSA and others continue today to 
try to explain this phenomenon.
    Second, OMB's apparent conclusion that increased installation of 
ABS in light vehicles could have a modest net safety benefit is based 
upon data that are not statistically significant. Those data are taken 
from a study by Charles M. Farmer for the Insurance Institute for 
Highway Safety (IIHS).\42\
---------------------------------------------------------------------------

    \42\ ``New Evidence Concerning Fatal Crashes by Passenger 
Vehicles Before and After Adding Antilock Braking System,'' Charles 
M. Farmer, Insurance Institute for Highway Safety, February 2000. A 
copy of this study has been placed in the docket. (Docket No. NHTSA-
2000-8572-206).
---------------------------------------------------------------------------

    In the April 15, 2000 edition of its Status Report, IIHS said the 
following about the study:

    New evidence suggests that cars with antilock braking systems no 
longer are disproportionately involved in certain types of fatal 
crashes. However, antilocks still aren't producing reductions in 
overall fatal crash risk * * *
    * * * As before, vehicles with antilock brakes were less likely 
than cars with standard brakes to be in crashes fatal to occupants 
of other vehicles. At the same time, the vehicles with antilocks no 
longer were found to be overinvolved in crashes fatal to their own 
occupants. Particularly important is the reduction in single-
vehicle, run-off-the-road crashes.

    The data from the Farmer study are set forth in the table below:

------------------------------------------------------------------------
                                 All crashes      95 Percent confidence
-----------------------------------------------          bounds
                                Fatalities in  -------------------------
                                   ABS cars
                                Fatalities in      Lower        Upper
                                 Non-ABS cars
------------------------------------------------------------------------
1. GM cars in 1993-95........  1.03...........         0.94         1.12
2. GM cars in 1996-98........  0.96...........         0.87         1.05
3. GM cars in 1993-98........  0.99...........         0.93         1.05
4. Non-GM cars in 1986-95....  1.16                    1.06         1.27
                                (Significant).

[[Page 38721]]

 
5. Non-GM cars in 1996-98....  0.91...........         0.77         1.06
6. Non-GM cars in 1986-98....  1.09                    1.01         1.18
                                (Significant).
------------------------------------------------------------------------

    A ratio of 1.0 in the second column means that ABS did not have any 
effect on fatalities. A ratio above 1.0 indicates a higher risk of 
fatalities in ABS-equipped vehicles, while a ratio below 1.0 indicates 
a lower risk of fatalities in ABS equipped vehicles.
    In order for the ratio for any group of vehicles to be 
statistically significant, both the lower and upper confidence bounds 
for that group must be either below 1.0 or above 1.0. This is true for 
only two groups of vehicles in the table: those in row 4, non-GM cars 
in 1986-95, and those in row 6, non-GM cars in 1986-98. For both of 
these groups, fatalities increased in ABS-equipped vehicles. Thus, in 
no subset of vehicles in the Farmer study is there any statistically 
significant advantage for ABS-equipped vehicles in crash fatalities.
    OMB interpreted the study to indicate a 4-9 percent reduction in 
fatalities in ABS-equipped vehicles.\43\ However, NHTSA does not 
believe that these data are statistically significant because one 
confidence bound is below 1.0 and the other is above 1.0. Thus, these 
alleged benefits are more than 5 percent likely to be due purely to 
chance.\44\
---------------------------------------------------------------------------

    \43\ The 4 percent figure is based on data for GM cars in 1996-
98, while the 9 percent figure is based on data for non-GM cars in 
1996-98.
    \44\ Most statisticians consider data that are more than 5 
percent likely to be due purely to chance to be statistically 
insignificant.
---------------------------------------------------------------------------

    Mr. Farmer, the study's author, has indicated to NHTSA that people 
might have learned how to better use ABS by calendar years 1996-98, so 
that they were no longer at as great a risk of run-off-the-road fatal 
crashes as in prior years.\45\ Even so, Farmer never stated in his 
study that ABS reduced fatalities. Regarding the Non-GM cars in 1996-
98, he stated, ``When all fatal crash involvements were considered, 
disregarding in which vehicle the fatalities occurred, the risk ratio 
was slightly lower than, but not significantly different from, 1.0.''
---------------------------------------------------------------------------

    \45\ Mr. Farmer indicated this in an ex parte conversation with 
Jim Simons of NHTSA on February 14, 2002. (Docket No. NHTSA-2000-
8572-210.)
---------------------------------------------------------------------------

    Third, the most recent NHTSA study showed an improved picture 
regarding benefits and disbenefits compared to earlier studies, but 
still no overall benefits in fatal crashes. \46\ The study examined ABS 
effects separately for passenger cars and light trucks for five types 
of crashes: frontal impacts, side impacts, rollover, run-off-the-road, 
and pedestrian.
---------------------------------------------------------------------------

    \46\ ``Analysis of the Crash Experience of Vehicles Equipped 
with All Wheel Antilock Braking Systems (ABS)--A Second Update 
Including Vehicles with Optional ABS,'' NHTSA, DOT HS 809 144, 
September 2000. A copy of this study has been placed in the docket. 
(Docket No. NHTSA-2000-8572-205.) It is also available at http://
www-nrd.nhtsa.dot.gov/vrtc/ca/capubs/lvabstask1--
crashdatareport.pdf.
---------------------------------------------------------------------------

    The study found that, when both non-fatal and fatal crashes were 
combined, there were reductions in crashes for vehicles equipped with 
ABS. ABS was found to result in statistically significant reductions in 
crashes for most types of crashes, except side impact crashes, 
especially those involving cars.
    However, when only fatal crashes were considered, there were not 
any statistically significant overall reductions of those crashes for 
ABS-equipped vehicles. In fact, the only statistically significant 
finding was that fatal light truck rollover crashes increased in 
vehicles with ABS as compared to vehicles without ABS. (That did 
represent an improvement over a 1998 study\47\ that found statistically 
significant increases for several types of crashes.) No statistically 
significant effects, positive or negative, were found for any type of 
fatal passenger car crashes or for other types of fatal light truck 
crashes.
---------------------------------------------------------------------------

    \47\ ``An Analysis of the Crash Experience of Passenger Vehicles 
with Antilock Braking Systems-An Update,'' NHTSA, DOT HS 808 758, 
August 1998.
---------------------------------------------------------------------------

    It is unclear whether the evidence in recent studies represents a 
statistical aberration relative to earlier studies or whether it is 
indicative of a real and positive trend. NHTSA will continue to monitor 
the real world performance of ABS on light vehicles. As with all 
protective devices, NHTSA plans to update its estimates for ABS as more 
data become available. If NHTSA obtains data enabling it to show that 
ABS reduces net fatalities and is cost/beneficial in light vehicles, 
the agency will consider initiating a separate rulemaking to address 
the issue of whether to require their installation.

F. Technical Foundation for NHTSA's Safety Benefit Analyses

    OMB recommended that NHTSA better explain the technical foundation 
for the agency's estimates of safety benefits and subject those 
estimates to sensitivity analyses.\48\ Since conducting these desired 
sensitivity analyses is relevant primarily to making a decision about 
the TPMS requirements for the long-term, the agency believes that its 
decision to postpone the final decision on TPMS requirements to the 
second part of this final rule makes it unnecessary to conduct 
additional sensitivity analyses at this time.
---------------------------------------------------------------------------

    \48\ When performing a sensitivity analysis, the agency changes 
assumptions it has made and then calculates differences in its 
benefits estimates. For example, the agency assumed that 20 percent 
of blowouts are caused by low tire pressure. If the agency performed 
a sensitivity analysis, it could change that assumption to 10 
percent or 30 percent and then calculate a potential range of 
benefits.
---------------------------------------------------------------------------

    The agency will complete its new study of TPMS by March 1, 2004. In 
this study, NHTSA will examine whether the tire pressure of vehicles 
without any TPMS are substantially closer to the vehicle manufacturer's 
recommended pressure than the tire pressure of vehicles with TPMSs, 
especially TPMSs that do not comply with the four-tire, 25 percent 
compliance option. If necessary, the agency will perform sensitivity 
analyses on these data.
    OMB specifically questioned the estimates of safety benefits that 
NHTSA made based on reduced skidding and better control, since these 
estimates were based on the Indiana Tri-level study published in 1977. 
The agency does not have later data of this quality on the effects of 
under-inflation on crashes. The agency has started to collect tire 
pressure data as part of its NASS-CDS data collection. However, NASS-
CDS is not a system designed to determine the cause of a crash. Thus, 
NHTSA does not anticipate receiving significant further data on this 
issue.\49\ However, if this issue becomes a critical element for the 
decision for the second part of this final rule, the agency will

[[Page 38722]]

perform sensitivity analyses on the data from the 1977 study.
---------------------------------------------------------------------------

    \49\ Although these data probably will not indicate whether low 
tire pressure caused a crash, the agency is collecting these data to 
determine the extent of the correlation between tire pressure and 
skidding/loss of control crashes.
---------------------------------------------------------------------------

    OMB also noted NHTSA's use of Goodyear data, rather than VRTC data, 
on the effects of under-inflation on stopping distance. As explained in 
greater detail in the FEA, the agency did not use the VRTC data because 
of its concerns with the way in which the tests were performed.\50\ The 
agency believes that the Goodyear test methodology adequately addressed 
these concerns.\51\
---------------------------------------------------------------------------

    \50\ For example, the VRTC only tested new tires, not worn tires 
that are more typical of the tires on most vehicles. In addition, 
the NHTSA track surface is considered to be aggressive in that it 
allows for maximum friction with tire surfaces. It is more 
representative of a new road surface than the worn surfaces 
experienced by the vast majority of road traffic.
    \51\ For example, Goodyear tested tires with two tread depths: 
full tread, which is representative of new tires, and half tread, 
which is representative of worn tires.
---------------------------------------------------------------------------

    In addition, OMB questioned the agency's use of the Goodyear data 
from a minivan to represent passenger cars. The critical element that 
is being measured is the difference in the tire's response when under-
inflated. It is true that the absolute stopping distance will vary by 
vehicle weight and other vehicle performance characteristics. However, 
these same characteristics will influence both the properly inflated 
and the under-inflated tests in a similar fashion. Therefore, while 
Goodyear's test sample was confined to only two vehicles (a Dodge 
Caravan and a Ford Ranger), the differences measured under various 
inflation levels should still be indicative of the effect that could be 
expected.
    Finally, OMB questioned NHTSA's assumption that under-inflation is 
involved in 20 percent of blowouts that cause crashes. The agency does 
not know precisely how many blowouts that cause crashes are influenced 
by under-inflation. As noted above in Section III.D.1., ``Reduced 
Vehicle Safety--Tire Failures and Increases in Stopping Distance,'' 
while the only tire-related data element in the agency's crash 
databases is ``flat tire or blowout,'' even in crashes for which a flat 
tire or blowout is reported, crash investigators cannot tell whether 
under-inflation contributed to the blowout. The agency's best estimate 
is that under-inflation plays a role in 20 percent of blowouts that 
cause crashes.
    In making this estimate, the agency was mindful of the fact that 
many blowouts occur when one tire is punctured, begins to lose air at a 
rate somewhat faster than the normal rate due to natural causes, and 
then fails after being driven for some time while under-inflated. In 
these cases, a TPMS meeting either compliance option would be able to 
warn the driver of the under-inflated tire before the tire failed, 
possibly avoiding a crash.
    NHTSA emphasizes that the choice of 20 percent as its estimate of 
the percentage of under-inflation's involvement in blowouts that cause 
crashes made little difference in the agency's benefits analyses. As 
noted below in Section VIII.A.3., ``Flat Tires and Blowouts,'' the 
agency estimates that the number of fatalities prevented per year due 
to reductions in crashes involving blowouts and flat tires will be 39 
if all light vehicles meet the four-tire, 25 percent compliance option, 
and 32 if all light vehicles meet the one-tire, 30 percent compliance 
option. The choice of a somewhat higher or lower figure for the 
percentage of under-inflation's involvement would change only 
negligibly the relative benefits of the two compliance options.

VII. The Final Rule

A. Decision To Issue Two-Part Final Rule

    As noted above, NHTSA was required to submit a draft final rule to 
OMB for review. The agency submitted a draft final rule to OMB on 
December 18, 2001. During the review process, OMB raised questions 
about the available data and the conclusions the agency preliminarily 
drew from them. OMB also raised questions about the effect of the final 
rule on the installation of ABS and the possibility of obtaining 
braking safety benefits as well as tire safety benefits.
    To allow for the consideration of additional data regarding the 
requirements for vehicles manufactured after October 31, 2006, the 
agency has decided to divide the final rule into two parts. In this 
first part, the agency is establishing the requirements for vehicles 
manufactured from November 1, 2003 to October 31, 2006.
    The agency will leave the rulemaking docket open for the submission 
of new data and analyses. During this period, the agency requests that 
commenters address how the performance characteristics of particular 
types of TPMSs satisfy the statutory requirement that systems provide a 
warning ``when a tire is significantly under-inflated.''
    NHTSA is especially interested in data and information about TPMS, 
both the systems in the field as well as systems under development. 
Commenters are urged to substantiate their comments with data and 
information to the maximum extent possible. Unsubstantiated comments 
are less useful.
    The agency also will conduct a study comparing the tire pressures 
of vehicles without any TPMS to the pressures of vehicles with TPMSs, 
especially TPMSs that do not comply with the four-tire, 25 percent 
compliance option. Based on the record compiled to this date, the 
results of that study, and any other new information submitted to the 
agency, NHTSA will issue the second part of this rule. The second part 
will be issued by March 1, 2005, and will apply to vehicles that are 
manufactured after October 31, 2006.
    Based on the record now before the agency, NHTSA tentatively 
believes that the four-tire, 25 percent option would best meet the 
mandate in the TREAD Act. However, it is possible that the new 
information may be sufficient to justify a continuation of the 
requirements in the first part of this rule, or some other alternative.

B. Part One of the Final Rule--November 2003 through October 2006

1. Summary
    The first part of this final rule establishes requirements for 
vehicles manufactured between November 1, 2003, and October 31, 2006, 
subject to a phase-in schedule.\52\ The final rule requires passenger 
cars, multipurpose passenger vehicles, trucks, and buses with a GVWR of 
4,536 kilograms (10,000 pounds) or less, except those vehicles with 
dual wheels on an axle, to be equipped with a TPMS to alert the driver 
that one or more of the vehicle's tires are significantly under-
inflated.
---------------------------------------------------------------------------

    \52\ Under the phase-in, 10 percent of a manufacturer's affected 
vehicles will have to comply with one of the two compliance options 
the first year (vehicles manufactured between November 1, 2003 and 
October 31, 2004); 35 percent will have to comply the second year 
(between November 1, 2004 and October 31, 2005); and 65 percent will 
have to comply the third year (between November 1, 2005 and October 
31, 2006).
---------------------------------------------------------------------------

    For these vehicles, the first part of the final rule provides two 
compliance options.\53\ Under the first compliance option, a vehicle's 
TPMS must warn the driver when the pressure in 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. Under the second compliance 
option, a vehicle's TPMS must warn the driver when the pressure in any 
one of the vehicle's tires is 30 percent or more below the vehicle 
manufacturer's recommended cold inflation pressure

[[Page 38723]]

for the tires, or a minimum level of pressure specified in the 
standard, whichever pressure is higher.\54\
---------------------------------------------------------------------------

    \53\ The agency is requiring manufacturers to irrevocably select 
the option to which they will certify each vehicle.
    \54\ As noted above, the minimum levels of pressure are the same 
for both compliance options.
---------------------------------------------------------------------------

    Vehicles certified to either compliance option will be required to 
provide written information in the owner's manual 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. Vehicles certified to the one-tire, 
30 percent option will be required to provide additional information on 
the inherent limitations of current indirect TPMSs.
    Under both compliance options, the TPMS must include a low tire 
pressure-warning telltale (yellow). Under the four-tire, 25 percent 
option, the telltale must remain illuminated as long as any of the 
vehicle's tires remains significantly under-inflated, and the key 
locking system is in the ``On'' (``Run'') position. The telltale can be 
deactivated automatically only when all of the vehicle's tires cease to 
be significantly under-inflated, or manually in accordance with the 
vehicle manufacturer's instructions.
    The one-tire, 30 percent option requires that the telltale remain 
illuminated as long as one of the vehicle's tires remains significantly 
under-inflated, and the key locking system is in the ``On'' (``Run'') 
position. The telltale can be deactivated automatically only when that 
tire ceases to be significantly under-inflated, or manually in 
accordance with the vehicle manufacturer's instructions.\55\
---------------------------------------------------------------------------

    \55\ Since indirect TPMSs do not actually monitor tire pressure, 
they must be told when the vehicle's tires have been re-inflated. 
Thus, indirect TPMSs require the driver to push a reset button after 
re-inflating the vehicle's tires.
---------------------------------------------------------------------------

    Both compliance options require that the low tire pressure-warning 
telltale perform a bulb-check at vehicle start-up.
    Under both compliance options, each TPMS must be compatible with 
all replacement or optional tires (but not rims) of the size(s) 
recommended for use on the vehicle by the vehicle manufacturer. The 
TPMS is not required to monitor the spare tire, either when it is 
stowed or when it is installed on the vehicle. The TPMS also does not 
have to indicate a system malfunction.
    In response to comments regarding the need to manually reset 
indirect TPMSs after adding pressure to the tires, the agency is 
permitting the warning telltale to be deactivated manually, in 
accordance with the vehicle manufacturer's instructions.
    In response to comments regarding variations in rim designs, the 
agency is requiring TPMSs to be compatible with all replacement or 
optional tires, but not rims, of the size(s) recommended for use on the 
vehicle by the vehicle manufacturer.
    In response to BTS survey data indicating that 65 percent of people 
would be less concerned to either a great extent or a very great extent 
with routinely maintaining their tire pressure if their vehicle were 
equipped with a TPMS, the agency is requiring the low tire pressure 
warning telltale to perform a bulb-check during vehicle start-up.
    In response to comments, the agency is also making minor changes to 
the required written instructions, and requiring vehicles certified to 
the one-tire, 30 percent option to provide additional information on 
the inherent limitations of current indirect TPMSs.
2. Congressional Intent
    Section 13 of the TREAD Act simply mandates ``a rulemaking for a 
regulation to require a warning system in new motor vehicles to 
indicate to the operator when a tire is significantly under inflated.'' 
None of the sources of legislative history commonly recognized as being 
legally authoritative, such as the House and Senate Reports or the 
Congressional Record, shed any light on the type of TPMS that Congress 
intended to mandate with this amendment.\56\
---------------------------------------------------------------------------

    \56\ The agency also notes that the issue of direct vs. indirect 
TPMSs was not before Congress when the bill that became the TREAD 
Act was being considered.
---------------------------------------------------------------------------

    In the absence of any legally authoritative sources, the Alliance 
turned in its comments to statements made by Congressman Markey, the 
sponsor of the TPMS amendment, as quoted in an unofficial transcript of 
the House Committee on Energy and Commerce markup of the bill that 
became the TREAD Act.\57\ In explaining and arguing for his amendment, 
Congressman Markey referred to a TPMS on an existing vehicle model. 
That TPMS was an indirect TPMS. Based on the Congressman's having 
mentioned an indirect TPMS in the course of his remarks, the Alliance 
argued that the Congressman must have intended that current indirect 
TPMSs be allowed under the rulemaking mandated by the TPMS amendment.
---------------------------------------------------------------------------

    \57\ This sort of legislative history is not entitled to much, 
if any, weight.
---------------------------------------------------------------------------

    While the Alliance's interpretation of Congressman Markey's 
statements during markup is not inconsistent with those statements, it 
goes well beyond anything that the Congressman directly said in them. 
Further, that interpretation is contrary to Congressman Markey's 
statements at the February 28, 2002 House Committee on Energy and 
Commerce hearing. In those later statements, Congressman Markey said 
that the intent of his TPMS amendment was to require TPMSs that provide 
warnings in all instances of under-inflation, thus suggesting a 
preference for direct TPMSs, which can provide such warnings, over 
current indirect TPMSs, which cannot. While those statements at the 
hearing likewise do not constitute any legally authoritative 
legislative history of the TREAD Act, they do suggest that the 
Alliance's interpretation of Congressman Markey's earlier statements is 
not persuasive.
3. Vehicles Covered
    The final rule requires TPMSs on passenger cars, multipurpose 
passenger vehicles, trucks, and buses with a GVWR of 4,536 kilograms 
(10,000 pounds) or less, except those vehicles with dual wheels on an 
axle. It does not require TPMSs on motorcycles, trailers, low-speed 
vehicles, medium vehicles, or heavy vehicles.
    NHTSA is not requiring TPMSs on motorcycles because, unlike the 
types of vehicles that are subject to the final rule, some motorcycles 
still use tubed tires. In order for a direct TPMS to work with tubed 
tires, the pressure sensor would not only have to be inside the tire, 
but also inside the tube itself. The agency is not aware of any TPMSs 
that are made to work with tubed tires. The agency requested comments 
on this issue but received none.
    Advocates recommended that the agency open rulemaking to set 
regulatory requirements for retreaded and recapped medium (10,001--
26,000 pounds GVWR) and heavy (over 26,000 pounds) vehicle tires. 
Advocates stated that there is a ``serious, pervasive problem of tire 
underinflation among medium and heavy vehicles, especially given the 
high percentage of trucks and buses above 10,000 pounds gross vehicle 
weight which use re-treaded tires.'' However, Advocates did not provide 
any data to support this statement.
    As discussed in the NPRM, NHTSA is not requiring TPMSs on medium 
(10,001--26,000 lbs. GVWR) and heavy (greater than 26,001 lbs. GVWR) 
vehicles at this time for two reasons. First, this rulemaking is 
required by the TREAD Act, which required a final rule to be issued in 
one year and was passed in response to problems with certain Firestone 
tires. Since those tires were

[[Page 38724]]

used on light vehicles, and the time frame was so tight, the agency has 
limited its study of under-inflation to light vehicles.
    Second, the issues associated with under-inflated tires on medium 
and heavy vehicles are different from and more complex than the issues 
associated with under-inflated tires on light vehicles. For example, 
medium and heavy vehicles are equipped with tires that are much larger 
and have much higher pressure levels than the tires used on light 
vehicles. In addition, medium and heavy vehicles are generally equipped 
with more axles and tires than light vehicles. Since the TREAD Act 
imposed a one-year deadline on this rulemaking, the agency did not have 
the time to study and analyze those issues sufficiently.
    The Alliance recommended that the agency limit the applicability of 
the standard to vehicles having a GVWR of 3,856 kilograms (8,500 pounds 
or less). The Alliance stated that the majority of vehicles above 8,500 
pounds GVWR are used commercially. The Alliance argued that such 
vehicles are maintained on a regular basis and do not need a TPMS to 
assist in maintaining proper inflation pressure in the vehicles' tires.
    NHTSA is aware of at least two non-commercial vehicle models--the 
Chevrolet Suburban and Ford Excursion, both SUVs--that have a GVWR 
between 8,500 and 10,000 pounds. In addition, 15-passenger vans are 
typically in this weight rating range. If the agency adopted the 
Alliance's recommendation, these vehicles would be excluded from the 
standard. These vehicles are as subject to under-inflated tires as 
other light SUVs and vans. Thus, the agency is not adopting the 
Alliance's suggestion.
    However, to address the Alliance's concern about the standard's 
applicability to commercial vehicles, the agency is excluding from the 
standard trucks, buses, and multipurpose passenger vehicles that have a 
GVWR under 10,000 pounds and dual wheels on an axle. This includes 
vehicles such as step vans, tow trucks, and some large pick-up trucks. 
The agency notes that these vehicles are normally used in a commercial 
capacity, and, as the Alliance argued, commercial vehicles normally 
undergo maintenance on a regular basis. Thus, these vehicles are less 
likely to experience significantly under-inflated tires. Moreover, 
since these vehicles have more wheels on an axle, they are less likely 
to experience the adverse effects on vehicle handling and other safety 
problems associated with significantly under-inflated tires.
    The Alliance also recommended that the agency explicitly exclude 
incomplete vehicles from the standard.\58\ Normally, the first-stage 
vehicle manufacturer is responsible for certifying that all vehicle 
systems that are not directly modified by subsequent-stage 
manufacturers meet all Federal motor vehicle safety standards. The 
Alliance stated that, in the case of direct TPMSs, the first-stage 
manufacturer will be unable to guarantee that, even if physically 
undisturbed, a non-defective TPMS will function as required after 
vehicle modifications (such as adding metal hardware to the vehicle or 
lengthening its wheelbase) are made by subsequent-stage manufacturers.
---------------------------------------------------------------------------

    \58\ 49 CFR Part 568.3 defines ``incomplete vehicle'' as ``an 
assemblage consisting, as a minimum, of frame and chassis structure, 
power train, steering system, suspension system, and braking system, 
to the extent that those systems are to be part of the completed 
vehicle, that requires further manufacturing operations, other than 
the addition of readily attachable components, such as mirrors or 
tire and rim assemblies, or minor finishing operations such as 
painting, to become a completed vehicle.''
---------------------------------------------------------------------------

    The agency notes that many incomplete vehicles are manufactured 
into custom vans and recreational vehicles. The agency believes that 
these vehicles should be equipped with the same or similar safety 
systems as passenger cars, multipurpose passenger vehicles, trucks, and 
buses. In particular, the agency believes that these types of vehicles 
should be equipped with a TPMS, as they are just as likely to 
experience significantly under-inflated tires as other light vehicles. 
In addition, the agency notes that if subsequent-stage manufacturers 
modify the TPMS on a vehicle, they will be responsible for certifying 
that the vehicle meets the standard. Therefore, the agency is not 
adopting the Alliance's suggested exclusion of incomplete vehicles.
4. Phase-In Options and Requirements
a. Alternatives Considered
    For purposes of this first part of the final rule, the agency 
considered four alternatives, three of which are discussed above in 
section V.A., ``Alternative Long-Term Requirements Analyzed in Making 
Preliminary Determination.'' The fourth alternative considered by the 
agency is the one-tire, 30 percent alternative suggested by OMB. This 
alternative would require a vehicle's TPMS to warn the driver when the 
pressure in any one of the vehicle's tires is 30 percent or more below 
the placard pressure, or a minimum level of pressure specified in the 
standard, whichever pressure is higher. The benefits and costs of the 
one-tire, 30 percent alternative are discussed above in section VI.C. 
``Analysis of a Fourth Alternative Long-Term Requirement: One-Tire, 30 
Percent Under-Inflation Detection.''
    While the agency ultimately considered four alternatives, in the 
NPRM the agency proposed only two alternative versions of a standard 
for TPMSs and requested comments on them. The two alternatives were the 
four-tire, 20 percent alternative and the three-tire, 25 percent 
alternative.
    To simplify the agency's analysis and discussion of the comments, 
NHTSA is separately addressing below the two most significant aspects 
of these two alternatives, i.e., the definition of the term 
``significantly under-inflated'' and the number of tires the TPMS 
should monitor.
    In the NPRM, the agency provided two alternate definitions of the 
term ``significantly under-inflated,'' and then used that term in 
specifying performance requirements for the low tire pressure warning 
telltale, while not specifying any performance requirements for the 
TPMS itself. After reviewing this approach to drafting and organizing 
the regulatory text, the agency decided to adopt a simpler, more direct 
approach. Instead of defining the term ``significantly under-inflated'' 
in the final rule, the agency is specifying performance requirements, 
including the threshold level of under-inflation that must trigger a 
warning, for two compliance options: the four-tire, 25 percent option 
and the one-tire, 30 percent option.
i. Threshold Level of Under-Inflation
    As explained above in section II.D, ``Summary of Public Comments on 
Notice,'' RMA recommended that the agency define ``significantly under-
inflated'' as any inflation pressure that is less than the pressure 
needed to carry the actual vehicle load on the tire per tire industry 
standards (or any pressure required to carry the maximum vehicle load 
on the tire if the actual load is unknown), or the minimum activation 
pressure specified in the standard, whichever is higher. RMA also 
recommended that the agency change the minimum activation pressures for 
P-metric standard load tires from 20 to 22 psi and for P-metric extra 
load tires from 23 to 22 psi. RMA also recommended that the agency 
change the ``Maximum Pressure'' heading in Table 1 to ``Maximum or 
Rated Pressure'' because light truck tires are not subject to maximum 
permissible inflation pressure labeling requirements. RMA recommended 
that the agency change

[[Page 38725]]

the rated pressure for Load Range E tires from 87 to 80 psi. Finally, 
RMA, supported by RIGAC, recommended that the agency adopt a 
requirement in the agency's separate rulemaking to upgrade Standard No. 
109, ``New Pneumatic Tires,'' that ``a tire for a particular vehicle 
must have sufficient inflation and load reserve, such that an inflation 
pressure 20 or 25 percent less than the vehicle manufacturer's 
recommended inflation pressure is sufficient for the vehicle maximum 
load on the tire, as defined by FMVSS-110.'' \59\
---------------------------------------------------------------------------

    \59\ Standard No. 110 specifies requirements for tire selection 
to prevent tire overloading.
---------------------------------------------------------------------------

    The ITRA recommended that the agency consider only direct TPMSs. 
The ITRA stated that indirect TPMSs have too many limitations, 
including the inability to detect when all four of a vehicle's tires 
are significantly under-inflated. The ITRA claimed that although direct 
TPMSs are more expensive than indirect TPMSs, their benefits outweigh 
their costs.
    The Alliance recommended that the agency define ``significantly 
under-inflated'' as any inflation pressure 20 percent below a tire's 
load carrying limit, as determined by a tire industry standardizing 
body (such as the Tire and Rim Association) or the minimum activation 
pressure specified in the standard, whichever is higher. The Alliance 
agreed with the agency's minimum activation pressure of 20 psi for P-
metric standard load tires.
    The Alliance also stated that a 25 percent differential from 
placard pressure would be inadequate to allow the use of indirect 
TPMSs. The Alliance claimed that a minimum of 30 percent differential 
is necessary to ensure accuracy with an indirect TPMS and avoid 
excessive nuisance warnings.
    The AIAM recommended that the agency define ``significantly under-
inflated'' as any pressure more than 30 percent below the placard 
pressure. Alternatively, the AIAM suggested that the agency use the 
load carrying limit of the tire as defined by a tire industry 
standardizing body as the baseline for determining the warning 
threshold.
    TRW stated that indirect TPMSs that are currently on the market 
could be improved to detect a 25 percent differential in inflation 
pressure. TRW stated this could be accomplished by adding the 
equivalent of two direct pressure sensors and a receiver to an indirect 
TPMS.
    Advocates supported the definition of ``significantly under-
inflated'' contained in the first alternative, i.e., any pressure 20 
percent or more below the placard pressure, or the minimum activation 
pressure specified in the standard, whichever is higher.
    The agency notes that both RMA and the Alliance recommend that the 
agency tie the definition of ``significantly under-inflated'' to the 
load carrying capacity of the tire rather than the placard pressure. 
NHTSA declines to adopt this recommendation for two reasons.
    First, the placard pressure provided by the vehicle manufacturer 
assumes loading at GVWR and also takes into consideration ride, 
handling, and other factors for safe vehicle operation. Some 
manufacturers also include a certain amount of reserve load capacity in 
the event that the tire is overloaded. Therefore, when tire pressure is 
down to 25 percent below the placard pressure, it is not necessarily 
below the pressure that is needed to safely carry the weight of the 
vehicle. Moreover, the agency notes that the calculations in the Tire 
and Rim Association (T&RA) tables are based on the volume of air in the 
tire, and do not consider differing performance capabilities of 
different tire materials or manufacturing quality.\60\
---------------------------------------------------------------------------

    \60\ These tables, contained in the T&RA yearbook, establish the 
load carrying capacity of a tire at a specific inflation pressure.
---------------------------------------------------------------------------

    Second, consumers are currently not familiar with using the T&RA 
tables to determine the correct tire inflation pressure for their 
vehicles. However, they do have some familiarity with using the 
vehicle's placard pressure to maintain proper inflation pressures. It 
would be counter-productive to introduce a new frame of reference for 
consumers to use at this time unless there are compelling reasons to do 
so.
    The agency agrees with the Alliance's statement that most current 
indirect TPMSs are not able to detect a 25 percent differential from 
placard pressure. Of the indirect TPMSs evaluated by the VRTC, only one 
was capable of activating the warning telltale at pressures at least 25 
percent below the placard pressure.\61\
---------------------------------------------------------------------------

    \61\ The indirect TPMS is manufactured by Continental Teves for 
the BMW M3. In the testing, it was able to detect when one, two 
(only if diagonally opposite each other) or three tires were 
significantly under-inflated.
---------------------------------------------------------------------------

    The agency believes that, as the technology matures, manufacturers 
will be able to improve the performance of indirect TPMSs. TRW, which 
manufactures both direct and indirect TPMSs, stated that the indirect 
TPMSs currently on the market could be improved to detect a 25 percent 
differential from placard pressure. However, TRW was not certain that 
these improvements could be developed and implemented by the 2003 
effective date of the final rule. Sumitomo's comments indicated that 
indirect TPMSs would be able to detect a 25 percent differential in 
inflation pressure. Toyota stated that its next generation of indirect 
TPMSs would be able to detect a 20 percent differential in tire 
pressure by monitoring the resonance frequency as well as the dynamic 
radius changes of the tires. Again, however, Toyota did not have a 
timetable for the introduction of this next generation of indirect 
TPMSs.
    Nevertheless, the fact remains that current indirect TPMSs are not 
capable of meeting a four-tire, 25 percent requirement. Accordingly, 
the agency is providing two compliance options in the first part of the 
final rule.\62\
---------------------------------------------------------------------------

    \62\ As noted above, the first part of this final rule covers 
vehicles manufactured from November 1, 2003 to October 31, 2006. 
During this period, the rule's requirements will be phased in 
according to the following schedule: 10 percent of a manufacturer's 
affected vehicles the first year, 35 percent the second year, and 65 
percent the third year. Beginning November 1, 2006, all affected 
vehicles will have to be equipped with a TPMS. These vehicles will 
have to comply with the requirements in the second part of this 
final rule. The agency will issue the second part of this final rule 
by March 1, 2005.
---------------------------------------------------------------------------

    These options will permit manufacturers to continue to use current 
indirect TPMSs while they continue to improve those systems. The agency 
notes that, for vehicles already equipped with ABS, the installation of 
a current indirect TPMS is the least expensive way of complying with 
the TPMS standard. Consumers will benefit from the resulting cost 
savings. The choice of compliance options will also give manufacturers 
the flexibility needed to innovate and improve the performance of the 
indirect TPMSs.
    NHTSA notes that in some cases, 30 percent below placard pressure 
will be less than 20 psi, the minimum activation pressure specified for 
P-metric tires in Table 1. For example, if a tire's placard pressure 
were 27 psi, 30 percent below that would be about 19 psi. This final 
rule requires the TPMS to activate the low tire pressure telltale at 20 
psi, not 19 psi. The agency has established the minimum activation 
pressures for the reasons given below. This final rule requires the 
telltale to be activated at the higher of the pressure that is 30 (or 
25) percent below the placard pressure or the minimum activation 
pressure in Table 1, whichever pressure is higher. Thus, if a vehicle's 
tires have a placard pressure below 28 psi, and the manufacturer 
chooses to comply with the one-tire, 30 percent option, the telltale 
must be activated at 20 psi.

[[Page 38726]]

    The agency is not adopting RMA's suggestion to change the minimum 
activation pressures for P-metric standard load tires from 20 to 22 psi 
and for P-metric extra load tires from 23 to 22 psi. As noted in the 
NPRM, the agency recently tested a variety of Standard Load P-metric 
tires at 20 psi with 100 percent load at 75 mph for 90 minutes on a 
dynamometer. None of the tires failed. This leads the agency to believe 
that warnings provided at or above that level will give drivers 
sufficient time to check and re-inflate their vehicles' tires before 
the tires fail. Moreover, in a different TREAD Act rulemaking, the 
agency proposed to upgrade its tire standard.\63\ Part of this upgrade 
would require tires to be tested at 20 psi under load and speed 
conditions. All tires would be required to pass this test after 
completing the proposed endurance test. The agency believes these 
proposed tests would ensure that tires are capable of operating safely 
for at least 90 minutes at the minimum activation pressures specified 
in Table 1 of this final rule. Finally, RMA provided no reason for this 
change. The agency notes that until 2001, the T&RA tables listed 20 psi 
as the minimum acceptable pressure for Standard Load P-metric tires. 
The agency does not know why this minimum pressure was changed to 22 
psi in the 2001 T&RA tables.
---------------------------------------------------------------------------

    \63\ Docket No. NHTSA-2000-8011. The NPRM was published at 67 FR 
10049, March 5, 2002.
---------------------------------------------------------------------------

    The agency is adopting RMA's suggestion to change the ``Maximum 
Pressure'' heading in Table 1 to ``Maximum or Rated Pressure'' because 
light truck tires do not have maximum permissible inflation pressure 
labeling requirements. The agency is also adopting RMA's suggestion to 
change the rated pressure for Load Range E tires from 87 to 80 psi. The 
agency is also changing the corresponding kPa value from 600 to 550, 
and the corresponding minimum activation pressure from 350 to 320 kPa 
(51 to 46 psi).
    The minimum activation pressures are set forth in the following 
table: \64\
---------------------------------------------------------------------------

    \64\ NHTSA notes that 1 psi equals 6.9 kPa. The agency has 
rounded the English conversions to the nearest psi.

                    Table 1--Low Tire Pressure Warning Telltale--Minimum Activation Pressure
----------------------------------------------------------------------------------------------------------------
                                             Maximum or rated inflation pressure           Minimum activation
                                     --------------------------------------------------         pressure
              Tire type                                                                -------------------------
                                               (kPa)                    (psi)              (kPa)        (psi)
----------------------------------------------------------------------------------------------------------------
P-metric-Standard Load..............  240, 300, or 350         35, 44, or 51                    140           20
P-metric-Extra Load.................  280 or 340               41 or 49                         160           23
Load Range C........................  350                      51                               200           29
Load Range D........................  450                      65                               260           38
Load Range E........................  550                      80                               320           46
----------------------------------------------------------------------------------------------------------------

    Moreover, as noted above, part of the Standard No. 109 upgrade 
would require tires to be tested at 20 psi under load and speed 
conditions. All tires would be required to pass this test after 
completing the proposed endurance test. The agency believes these 
proposed tests, in effect, would require tires to have a reserve load.
ii. Number of Tires Monitored
    As noted above, in the NPRM the agency proposed two alternatives: 
the four-tire, 20 percent alternative and the three-tire, 25 percent 
alternative. The agency specified only three tires in the three-tire, 
25 percent alternative because currently available indirect TPMSs are 
not able to detect when all four of a vehicle's tires became 
significantly under-inflated.
    Advocates, ITRA, and RMA recommended that the agency require TPMSs 
to detect when all four of a vehicle's tires become significantly 
under-inflated. RMA argued that it is very likely that all four tires 
will lose air pressure at a similar rate and become significantly 
under-inflated within a six-month period.\65\ RMA stated that drivers 
would rely heavily on TPMSs for tire pressure maintenance, which will 
make this scenario even more likely.
---------------------------------------------------------------------------

    \65\ RMA states that normal air pressure loss is approximately 1 
to 2 psi per month.
---------------------------------------------------------------------------

    The Alliance and AIAM recommended that the agency require TPMSs to 
detect significant under-inflation in only one of a vehicle's tires. 
The Alliance argued that TPMSs are not meant to replace the normal tire 
maintenance that would detect pressure losses due to natural leakage 
and permeation. Rather, TPMSs are designed to detect a relatively slow 
leak due to a serviceable condition, such as a nail through the tread 
or a leaky valve stem. Since such leaks rarely affect more than one 
tire simultaneously, the Alliance argued, it is sufficient to require 
TPMSs to detect only one significantly under-inflated tire.
    The Alliance also claimed that if the agency required that more 
than one significantly under-inflated tire be detected simultaneously, 
manufacturers would not be able to use an indirect TPMS. The Alliance 
stated that indirect TPMSs look at wheel speed to calculate relative 
differences in the size of the rolling radii of the four wheels. 
However, due to load variances, steering effects, and variations in 
tire characteristics, differences in wheel speed must be compared 
between tires on opposite sides of the vehicle for the algorithm to 
reliably identify a relative pressure difference.
    TRW stated that current indirect TPMSs could be improved to be able 
to detect more than one significantly under-inflated tire. TRW stated 
that this could be accomplished by adding a direct sensor to two 
wheels, one on each side of the vehicle.
    NHTSA agrees with the Alliance's comment that TPMSs should not 
replace normal tire maintenance. The agency also accepts the Alliance's 
comment that most current indirect TPMSs would have difficulty 
detecting when more than one of a vehicle's tires is significantly 
under-inflated. As noted above, while the VRTC found that indirect 
TPMSs did warn the driver when one tire, two tires located diagonally 
from each other, and three tires were significantly under-inflated, the 
indirect TPMSs did not warn the driver when all four of a vehicle's 
tires, or two tires on the same axle or the same side of the vehicle, 
were significantly under-inflated.
    However, the agency also believes that TPMSs should do more than 
detect a relatively slow leak due to a serviceable condition. There are 
other

[[Page 38727]]

reasonably foreseeable circumstances in which significant under-
inflation may occur. Further, the agency believes that many drivers 
will rely on the TPMS to prompt them to do inflation pressure 
maintenance. As noted above, data from the July 2001 BTS omnibus survey 
indicated that 65 percent of drivers would be less concerned with 
routinely maintaining their tire pressure if their vehicle were 
equipped with a TPMS.
    The agency has data indicating that tires typically lose about 1 
psi per month due to natural leakage and permeation. Although all four 
of a vehicle's tires probably will not lose pressure at exactly the 
same rate, they will lose some pressure. Thus, it is likely that all 
four of a vehicle's tires will be somewhat under-inflated at any time.
    According to data from the February 2001 NCSA survey detailed 
above, 12 percent of passenger cars and 15.3 percent of light trucks 
with P-metric tires had at least two tires under-inflated by at least 
25 percent; 5 percent of passenger cars and 7.2 percent of light trucks 
had at least three tires under-inflated by at least 25 percent; and 2.8 
percent of passenger cars and 3.9 percent of light trucks had at least 
four tires under-inflated by at least 25 percent. If the agency adopted 
the Alliance's one-tire, 30 percent recommendation permanently, drivers 
of some vehicles, e.g., those equipped with current indirect TPMSs, 
would not be alerted to some of these potentially dangerous conditions. 
While these percentages are small, when applied to the entire light 
vehicle fleet (over 200,000,000 vehicles), these percentages translate 
into about 7,000,000 vehicles having all four tires significantly 
under-inflated at any time.
    If the agency adopted the Alliance's recommendation permanently, 
TPMSs would only be required to detect when one of a vehicle's tires 
became under-inflated by 30 percent or more below placard pressure. As 
a result, TPMSs would not be required to detect many situations 
involving significant under-inflation in the real world. Consequently, 
the agency tentatively believes that, in the long-term, the four-tire, 
25 percent option would best meet the mandate in the TREAD Act and best 
serve the American public.
    However, as noted above in section VII.B.4.a.i., ``Threshold Level 
of Under-Inflation,'' the agency wants to allow vehicle manufacturers 
to use current indirect TPMS in the short run, i.e., during the first 
part of this final rule, and to give them additional time to improve 
indirect TPMSs or develop hybrid TPMSs. The comments from TRW, 
Sumitomo, and Toyota indicate that current indirect TPMSs can be 
improved (whether by monitoring the resonance frequency of tires or by 
creating hybrid systems) to detect more than one significantly under-
inflated tire.
    To reconcile the limitations of current indirect TPMSs with the 
agency's belief that such systems can and should be improved to enhance 
safety, NHTSA has decided to give manufacturers two compliance options 
during the first part of this final rule period, i.e., from November 1, 
2003 through October 31, 2006.\66\
---------------------------------------------------------------------------

    \66\ The agency is requiring manufacturers to irrevocably select 
the option to which they will certify their vehicles.
---------------------------------------------------------------------------

b. Option One: Four Tires, 25 Percent Under-Inflation
    Under the first compliance option, a vehicle's TPMS must warn the 
driver when the pressure in 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. Vehicles certified to this compliance option also will have 
to comply with the remainder of the performance requirements, discussed 
below in section VII.B.5., ``Other Requirements,'' with the exception 
of the special written instructions for vehicles certified to the one-
tire, 30 percent compliance option.
    This compliance option is limited to light vehicles manufactured 
between November 1, 2003, and October 31, 2006. Light vehicles 
manufactured after October 31, 2006 will be subject to the requirements 
of the second part of this final rule, which the agency will publish by 
March 1, 2005. The remainder of the performance requirements, except 
for the special written instructions required for vehicles certified to 
the one-tire, 30 percent compliance option, will apply to light 
vehicles manufactured on or after November 1, 2003. c. Option Two: One 
Tire, 30 Percent Under-Inflation
    Under the second compliance option, a vehicle's TPMS must warn the 
driver when the pressure in any one of the vehicle's tires is 30 
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.\67\ Vehicles 
certified to this compliance option also will have to comply with the 
remainder of the performance requirements, discussed below in section 
VII.B.5. ``Other Requirements,'' including the special written 
instructions for vehicles certified to the one-tire, 30 percent 
compliance option.
---------------------------------------------------------------------------

    \67\ As noted above, the minimum levels of pressure are the same 
for both compliance options.
---------------------------------------------------------------------------

    This compliance option also is limited to light vehicles 
manufactured between November 1, 2003, and October 31, 2006. Light 
vehicles manufactured after October 31, 2006 will be subject to the 
requirements of the second part of this final rule, which the agency 
will publish by March 1, 2005. The remainder of the performance 
requirements, except for the special written instructions requirement, 
will apply to light vehicles manufactured on or after November 1, 2003.
d. Special Written Instructions for Option Two TPMSs
    In the NPRM, the agency proposed that the vehicle owner's manual 
provide an image of the TPMS warning telltale and the following 
information, in English:

    When the TPMS warning light is lit, one of your tires is 
significantly under-inflated. You should stop and check your tires 
as soon as possible, and inflate them to the proper pressure as 
indicated on the vehicle's tire inflation placard. Driving on an 
under-inflated tire causes the tire to overheat and can eventually 
lead to tire failure. Under-inflation also reduces fuel efficiency 
and tire tread life, and may affect the vehicle's handling and 
stopping ability.

    The agency also proposed to allow each vehicle manufacturer, at its 
discretion, to provide additional information about the significance of 
the low tire pressure warning telltale and description of corrective 
action that should be undertaken.
    The Alliance stated that it was not opposed to the language the 
agency proposed. However, the Alliance recommended that the agency 
include additional language addressing inherent system limitations, 
owner/driver responsibility, and replacement tires and rims. The 
Alliance did not recommend any specific language.
    NHTSA is accepting this Alliance comment. The agency notes that 
indirect TPMSs have several limitations, including the inability to 
detect when all four tires, and other combinations of tires, are 
significantly under-inflated. In addition, the agency notes that data 
from the July 2001 BTS omnibus survey indicate that 65 percent of 
drivers would be less concerned to a great extent or a very great 
extent with routinely maintaining their tire pressure if their vehicle 
were equipped with a TPMS. This substantial shift in reliance from 
routine maintenance to TPMS

[[Page 38728]]

concerns the agency, given the performance limitations of indirect 
TPMSs. To avoid the creation of a false sense of security, therefore, 
the agency is requiring vehicle manufacturers to provide additional 
information on the inherent limitations of TPMSs, if the vehicle is 
certified to the one-tire, 30 percent option. The additional 
information must immediately follow the general written instructions 
for all TPMSs, specified below, and read, in English, as follows:


    Note: The TPMS on your vehicle will warn you when one of your 
tires is significantly under-inflated and when some combinations of 
your tires are significantly under-inflated. However, there are 
other combinations of significantly under-inflated tires for which 
your TPMS may not warn you. These other combinations are relatively 
common, accounting for approximately half the instances in which 
vehicles have significantly under-inflated tires. For example, your 
system may not warn you when both tires on the same side or on the 
same axle of your vehicle are significantly under-inflated. It is 
particularly important, therefore, for you to check the tire 
pressure in all of your tires regularly and maintain proper 
pressure.

5. Other Requirements
a. Time Frame for Telltale Illumination
    NHTSA notes that in the NPRM the agency included this performance 
requirement in the requirements for the low tire pressure warning 
telltale. After reviewing this arrangement, however, the agency has 
decided that it was confusing. Thus, in the regulatory text of this 
final rule, the agency has shifted this performance requirement to the 
section of the regulatory text that specifies requirements for TPMSs.
    In the NPRM, the agency proposed that the warning telltale 
illuminate not more than ten minutes after a tire becomes significantly 
under-inflated.
    Advocates supported a much briefer time period, but did not specify 
a time period. Advocates stated that the agency had given no reason for 
a ten-minute time period. RMA stated that the earlier the driver is 
warned the better, but also did not specify a time period.
    The Alliance stated that a detection window of ten minutes likely 
would be problematical for indirect TPMSs, which require different 
detection times at different speeds. The Alliance recommended that the 
detection requirement be changed to a driving interval of ten miles (16 
kilometers) instead of ten minutes to accommodate indirect TPMSs.
    According to data from the tire industry, 85 percent of tire 
pressure losses are slow pressure losses, in which it takes anywhere 
from several minutes to several weeks for a tire to become 
significantly under-inflated. The other 15 percent of tire pressure 
losses are rapid pressure losses, which typically result from a tire 
being punctured (without the puncturing object becoming embedded in the 
tire) or ruptured. TPMSs are designed to alert the driver to slow 
pressure losses, not rapid pressure losses. In addition, as noted 
above, all of the tires that the agency tested for endurance at 20 psi 
for 90 minutes passed. Thus, the agency believes that ten minutes 
between the time that a tire becomes significantly under-inflated and 
the time that the TPMS illuminates the low tire pressure warning 
telltale will provide the driver ample time to take corrective action 
and avoid the possibility of serious tire degradation. Accordingly, the 
agency is not adopting Advocates' suggestion that the agency shorten 
the time frame for telltale activation.
    The agency notes that the test procedures proposed in the NPRM 
specified a test speed of 50 to 100 km/h. That means it would take a 
vehicle about 10 to 20 minutes to travel the 16 kilometers proposed by 
the Alliance. The agency also notes that in its survey of TPMSs, 
NHTSA's VRTC found that direct TPMSs could illuminate the warning 
telltale in less than one minute after a tire became significantly 
under-inflated (by 50 percent under placard pressure). The VRTC also 
found that indirect TPMSs took from less than a minute to over eight 
minutes. This leads the agency to believe that ten minutes is ample 
time for both direct and indirect TPMSs.
    Thus, the agency is not adopting the Alliance's suggestion that the 
agency change the detection requirement to a driving interval of ten 
miles instead of ten minutes.
    Accordingly, for the four-tire, 25 percent option, this final rule 
requires that the TPMS illuminate the low tire pressure warning 
telltale not more than ten minutes after the inflation pressure in one 
or more tires, up to total of four tires, is 25 percent or more below 
the placard pressure, or a minimum level of pressure specified in the 
standard, whichever pressure is higher. For the one-tire, 30 percent 
option, this final rule requires that the TPMS illuminate the low tire 
pressure warning telltale not more than ten minutes after the pressure 
in one tire is 30 percent or more below the placard pressure, or a 
minimum level of pressure specified in the standard, whichever pressure 
is higher.\68\
---------------------------------------------------------------------------

    \68\ As noted above, the minimum levels of pressure are the same 
for both options.
---------------------------------------------------------------------------

b. Duration of Warning
    NHTSA notes that in the NPRM the agency included this performance 
requirement in the requirements for the low tire pressure warning 
telltale. After reviewing this arrangement, however, the agency has 
decided that it was confusing. Thus, in the regulatory text of this 
final rule, the agency has shifted this performance requirement to the 
requirements for TPMSs.
    In the NPRM, the agency proposed to require that the warning 
telltale be illuminated as long as any of the vehicle's tires remains 
significantly under-inflated, and the ignition switch is in the ``On'' 
(``Run'') position, whether or not the engine is running. The agency 
also proposed that the telltale be deactivatable, manually or 
automatically, only when all of the vehicle's tires cease to be 
significantly under-inflated.
    Advocates and RMA supported this proposal. Advocates stated that if 
manual disengagement of the illuminated telltale were permitted, a 
driver could indefinitely defer inspecting and correcting a 
significantly under-inflated tire simply by manually disengaging the 
telltale.
    Johnson Controls, Inc. (JCI), a manufacturer of both direct and 
indirect TPMSs, was concerned that a strict reading of NHTSA's 
proposals may preclude a driver's ability to access other information 
when the significant under-inflation telltale is activated within a 
multi-functional console display. JCI argued that the agency should 
allow sufficient flexibility to permit the vehicle occupant to check 
other information on a multi-functional display even in a significant 
under-inflation situation. According to JCI, with current center 
displays in vehicles that incorporate a TPMS feature, the owner is 
allowed to toggle between features on the display. For example, on 
certain current tire and non-tire specific displays located in center 
consoles, the low pressure display will persist until the vehicle 
occupant chooses to view another display (e.g., a miles to empty 
display). In that circumstance, the new display will remain active for 
a period of 60 seconds and then the pressure warning will be 
redisplayed. In some instances, the redisplay will be accompanied by an 
audible warning. JCI argued that as long as alternative displays are 
selected by the vehicle occupant as a matter of conscious

[[Page 38729]]

choice and are of sufficiently short duration, the cautionary function 
of the display will be preserved. Accordingly, JCI recommended amending 
Section 4.2.1(e) to read as follows:

    S4.2.1(e) Can be deactivated, manually or automatically, only 
when all of the vehicle's tires cease to be significantly under-
inflated, or when the vehicle occupant chooses to view another 
feature on the same display provided that the pressure cautionary 
message is automatically redisplayed not more than 60 seconds after 
the display is toggled to another feature.

    The Alliance stated that the requirement that the warning telltale 
be deactivated, manually or automatically, only when all of the 
vehicle's tires cease to be significantly under-inflated requires the 
vehicle to ``know'' that all the tires have ceased to be significantly 
under-inflated. This would prohibit the use of indirect TPMSs, which do 
not measure actual inflation pressure, and are therefore incapable of 
``knowing'' when the tires are no longer significantly under-inflated. 
This is the reason indirect TPMSs come with a manual re-calibration 
capability--because all indirect TPMSs must be ``told'' that repair, 
rotation, replacement, or re-inflation has occurred.
    The Alliance also noted that some vehicles have different placard 
pressures for the front and rear tires. For these vehicles, the TPMS 
warning cannot be fully automated. The driver or service agent must 
manually recalibrate the TPMS after rotating or correctly inflating the 
tires. For these reasons, the Alliance recommended amending Section 
4.2.1(d) to read as follows:

    S4.2.1(d) Remains activated (continuously or periodically) until 
automatically deactivated when all of the vehicle's tires cease to 
be significantly under-inflated or until manually deactivated in 
accordance with manufacturer's instructions.

    NHTSA is not adopting JCI's suggestion because the agency does not 
believe the driver should be able to temporarily deactivate the warning 
telltale, even if the deactivation can only last for 60 seconds. The 
agency does not normally allow warning telltales to be temporarily 
deactivated by the driver. The agency also believes that the warning 
telltale should be separate from a reconfigurable display.
    However, NHTSA is adopting the Alliance's suggestion that the 
agency allow the warning telltale to be manually extinguished in 
accordance with the vehicle manufacturer's instructions. The agency 
agrees with the Alliance's arguments. An indirect TPMS cannot ``know'' 
when a tire is no longer significantly under-inflated because it does 
not actually measure inflation pressure. An indirect TPMS must be told 
that the significantly under-inflated tire has been re-inflated. This 
is done with a manual reset button.
    The agency noted in the NPRM that a reset button may invite human 
error. For example, a driver may accidentally press the reset button 
when one or more of the vehicle's tires are under-inflated, but not 
significantly under-inflated. This would re-calibrate the system so 
that the under-inflated condition would be accepted as a normal 
variable. The indirect TPMS then would not be able to detect a 
significantly under-inflated tire until one or more tires were 25 
percent lower than it already was. This could also occur as a result of 
misuse, i.e., if the driver simply pressed the reset button when the 
warning telltale illuminated. The telltale would be extinguished 
without the driver having taken any corrective action.
    While NHTSA is concerned by these potential problems, the agency 
notes that indirect TPMSs must have a reset button. Moreover, direct 
TPMSs need a reset button under certain circumstances. For example, 
some vehicle manufacturers specify more than one placard pressure for a 
vehicle's tires--one applicable when the vehicle is lightly loaded and 
another when the vehicle is at maximum load. If a manual reset were not 
allowed, then the direct system would not know that the applicable 
recommended inflation pressure had changed.
    In addition, these human error problems are no different from the 
driver simply ignoring the warning telltale if it is illuminated. The 
agency can attempt to prevent these problems only through driver 
education. Thus, the agency will allow the warning telltale to be 
deactivated manually in accordance with the vehicle manufacturer's 
instructions.
    Accordingly, the agency is adding paragraph S4.2.1(b) to the 
requirements for the four-tire, 25 percent option, to read as follows:

    (b) Continue to illuminate the low tire pressure warning 
telltale as long as the pressure in any of the vehicle's tires is 
equal to or less than the pressure specified in (a), and the key 
locking system is in the ``On'' (``Run'') position, whether or not 
the engine is running, or until manually reset in accordance with 
the vehicle manufacturer's instructions.

    The requirement for the one-tire, 30 percent option is slightly 
different because under that option the TPMS only has to be able to 
detect when one tire is 30 percent or more below the placard pressure. 
Accordingly, the agency is adding paragraph S4.2.2(b) to the 
requirements for the one-tire, 30 percent option, to read as follows:

    (b) Continue to illuminate the low tire pressure warning 
telltale as long as the pressure in that tire is equal to or less 
than the pressure specified in (a), and the key locking system is in 
the ``On'' (``Run'') position, whether or not the engine is running, 
or until manually reset in accordance with the vehicle 
manufacturer's instructions.

c. Temporary Disablement
    The Alliance noted that TPMSs might be disabled, deliberately or by 
default, under certain conditions. For example, TPMSs could be disabled 
on four-wheel-drive applications whenever the vehicle is operated in 
``4WD Lo'' mode, typically during off-road use, or under very poor road 
conditions. The Alliance noted that most manufacturers of four-wheel-
drive vehicles recommend that the tires be deflated to a lower pressure 
during certain conditions of off-road use. A TPMS calibrated to a 
threshold appropriate for on-road use would otherwise provide an 
unnecessary warning under this special condition. The Alliance also 
stated that certain types of all-wheel-drive vehicles that selectively 
lock the differential under specific operating conditions typically 
disable the TPMS under these conditions. The Alliance concluded that 
such selective disablement is inconsequential to safety, as vehicles 
operating under such conditions are generally moving at relatively slow 
speeds where low tire pressure is not a significant safety concern.
    The Alliance also stated that TPMSs may be temporarily disabled or 
reduced in detection sensitivity by default due to technical limits on 
system capability. For example, indirect TPMSs are not capable of 
operating normally on rough roads, or at very high speeds (i.e., above 
75 mph) where the high centrifugal force prevents accurate detection of 
differences in rolling radius. Direct TPMSs are not capable of 
operating when radio frequency interference disrupts the transmission 
of sensor signals between the wheel sensors and the receiver, or when a 
tire without a sensor (such as a temporary spare) is installed on the 
vehicle.
    NHTSA has decided to prohibit any control that automatically 
disables the TPMS under any condition. The agency normally does not 
allow safety systems to be disabled, and the Alliance has provided no 
good reason for allowing the TPMS to be disabled. If drivers lower 
their tire pressure before off-road driving, and the low tire pressure 
warning telltale illuminates, it will serve as a reminder to the 
drivers to re-

[[Page 38730]]

inflate their tires before returning to the road. The agency does not 
believe that drivers will be inconvenienced if the telltale illuminates 
while they are driving off-road. Moreover, the Alliance indicated that 
drivers may also shift into ``4WD-Lo'' while driving on very poor road 
conditions. Since tire under-inflation plays a role in vehicle handling 
and stability, the agency believes that it is especially important that 
the TPMS be functioning when the vehicle is being driven on poor road 
conditions.
    Finally, the agency notes that all technology has limitations, and 
there may be situations in which the TPMS may not function properly. 
The agency considered those situations in specifying the test 
conditions and procedures in this standard. The agency will not perform 
compliance tests under any conditions or procedures that would prevent 
TPMSs from functioning properly.
d. System Calibration
    In the NPRM, the agency noted that most indirect TPMSs need time to 
calibrate the system, i.e., to ``learn'' the variables associated with 
distinct tire types under varying driving conditions. In its survey of 
current TPMSs, the VRTC found that the four indirect TPMSs it evaluated 
took anywhere from several minutes to several hours to calibrate. This 
calibration is necessary when a vehicle is driven for the first time 
(i.e., when it is new), when the pressure in a tire is changed, and 
when the tires are rotated or replaced. During the calibration mode, an 
indirect TPMS's ability to monitor tire pressure is severely limited. 
Thus, if one or more tires became significantly under-inflated while 
the system was calibrating, the driver might not be alerted.
    The agency did not propose in the NPRM that the TPMS indicate to 
the driver that the system is in calibration mode. However, in the 
proposed test procedures, the agency specified that the vehicle be 
driven for 20 minutes to allow for system calibration. Thus, in effect, 
the agency required that TPMSs be able to calibrate within 20 minutes 
of driving.
    The Alliance recommended that the agency allow manufacturers to 
provide, but not require, a calibration notification feature. The 
Alliance stated that recalibration generally takes place after the 
driver inflates the tires to the correct pressure. The driver then 
would be aware that calibration was taking place. The Alliance also 
argued that the likelihood of another significantly under-inflated tire 
occurring during the recalibration time frame is extremely low.
    TRW recommended that the agency not require indirect TPMSs to 
indicate that they are in calibration mode. TRW stated that this 
feature would not be necessary with direct TPMSs because they do not 
require calibration.
    The agency has decided not to require that the TPMS indicate when 
it is in calibration mode. The agency notes that calibration is 
necessary only for indirect TPMSs, and then it is necessary only when a 
vehicle is driven for the first time, when the pressure in a tire is 
changed, and when the tires are rotated or replaced. These are all 
times when significant under-inflation due to a slow leak should not be 
a problem. At these times, the tires either will be new or will have 
been checked. In addition, the agency notes that the driver is not able 
to take any action when given an indication of system calibration. For 
these reasons, the agency does not believe that a calibration 
indication feature would provide any safety benefits. However, if 
manufacturers wish to provide a calibration notification feature, they 
are free to do so. The agency is not prohibiting such a feature.
e. Replacement Tires
    In the NPRM, the agency proposed to require that each TPMS be able 
to function properly when any of the vehicle's original tires or rims 
are replaced with any optional or replacement tire or rim of the 
size(s) recommended for use on the vehicle by the vehicle manufacturer.
    RMA supported the agency's proposal. Advocates recommended that the 
agency require TPMSs to function properly with all replacement tires 
and rims, regardless of size.
    The Alliance recommended that the agency require TPMSs to function 
properly only with those tires and rims offered as original or optional 
equipment by the vehicle manufacturer. The Alliance stated that there 
are a large number of replacement brands and types of tires and rims 
with different dynamic rolling radii, size variations, load variations, 
and temperature characteristics. The Alliance argued that since vehicle 
manufacturers do not control tire compliance for aftermarket tires and 
rims, they cannot guarantee that the TPMS will work, or will work with 
the same level of precision, in all cases.
    JCI requested that the agency clarify that it was not requiring 
TPMSs to function when custom tires and rims not recommended by the 
vehicle manufacturer are installed on the vehicle. JCI stated that both 
indirect TPMSs (because of tire diameter changes and different tire 
pressure thresholds) and direct TPMSs (because of the potential 
inability to install and operate the transmitter) are compromised by 
such installations.
    The Specialty Equipment Market Association (SEMA) claimed that the 
proposed rule would have a major effect on business that sell 
aftermarket tires and rims. SEMA was concerned that the rule could: (1) 
Disallow aftermarket equipment that does not match the vehicle 
manufacturer's recommendations; (2) fail to require manufacturers to 
implement the TPMS in a manner that allows reprogramming by aftermarket 
installers; (3) fail to require that vehicle manufacturers design tire 
pressure sensors to be compatible with aftermarket tire and wheel 
combinations and standardized communication protocols to ensure that 
aftermarket sensors are compatible with OEM systems; (4) fail to direct 
consumers to inflate the tire to the pressure for the specific wheel 
and tire combination in use; and (5) render servicing by independent 
repair facilities more difficult.
    In this final rule, the agency is requiring that each TPMS meet the 
requirements of the standard when any of the vehicle's original tires 
are replaced with any optional or replacement tire of the size(s) 
recommended for use on the vehicle by the vehicle manufacturer and 
installed on the original rims. This requirement is the same for TPMSs 
complying with the four-tire, 25 percent option or the one-tire, 30 
percent option.
    The agency is not requiring that TPMSs meet the requirements of the 
standard when any of the vehicle's original rims are replaced with any 
optional or replacement rim of the size recommended for use on the 
vehicle by the vehicle manufacturer. The agency notes that since most 
direct TPMS sensors are mounted on the rim, the rim must be of a design 
that will accommodate the sensor. Some aftermarket rims may be the same 
size as the original rim, but have a design that will not accommodate a 
TPMS sensor. Thus, the agency does not believe that requiring TPMSs to 
work with all replacement rims of the same size recommended for use by 
the vehicle manufacturer is feasible.
    However, the agency does believe that requiring TPMSs to work with 
all replacement tires of the same size recommended by the vehicle 
manufacturer is feasible. The agency notes that while tires may have 
different designs, they are basically designed to

[[Page 38731]]

meet tire industry standards. The agency also notes that aftermarket 
direct TPMSs currently are available on the market. These TPMSs 
necessarily must be able to function regardless of the brand of tire. 
Moreover, RMA supported the agency's proposal to require TPMSs to work 
with all replacement tires of the same size or size recommended by the 
vehicle manufacturer. RMA did not state that this would be impossible 
due to differences in tire brands.
    The agency emphasizes that this requirement only applies to 
replacement tires that are of a size recommended for use on the vehicle 
by the vehicle manufacturer. It does not apply to any tires of a size 
not recommended for use on the vehicle by the vehicle manufacturer. If 
a tire retailer or repair business installs these tires on a vehicle, 
neither this final rule nor the statute under which it is issued 
requires the vehicle's TPMS to continue to meet the requirements of the 
final rule.
    NHTSA notes that 49 U.S.C. 30122 prohibits manufacturers, 
distributors, dealers, and motor vehicle repair businesses from 
knowingly making 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 Federal motor vehicle safety standard. 
The agency has determined that if such a business installed on a 
vehicle aftermarket rims that are not identical to the original rims, 
or tires that are not of the same size recommended for use on the 
vehicle by the vehicle manufacturer, the business would not violate the 
make inoperative provision. However, if such a business knowingly 
renders a vehicle's TPMS inoperative while rotating the vehicle's tires 
or installing tires that are of the same size recommended for use on 
the vehicle by the vehicle manufacturer, and does not repair the TPMS, 
the business has violated the make inoperative provision.
f. Monitoring of Spare Tire
    In the NPRM, the agency did not propose that the TPMS be required 
to monitor the pressure in the spare tire because NHTSA does not 
require vehicles to be equipped with a spare tire.
    Advocates and RMA recommended that the agency require TPMSs to 
monitor a vehicle's spare tire. RMA argued that the spare tire should 
be monitored to ensure its functionality, if and when it is needed. 
Advocates stated, ``Vehicle owners chronically neglect to maintain 
minimal air pressure in spare tires.'' However, Advocates did not 
provide any evidence to support its position.
    The Alliance recommended that the agency require TPMSs to monitor 
only matching, full-size spare tires, and only when they are installed 
on the vehicle (i.e., not while they are stowed). The Alliance stated 
that temporary-use spare tires, including full-size, non-matching and 
compact spare tires, are not intended to be part of the normal tire 
rotation cycle for the vehicle. Because these temporary-use spare tires 
degrade the esthetic appearance or have speed and distance limitations, 
vehicle owners normally replace them quickly. Thus, the Alliance 
recommended that the agency not require TPMSs to monitor temporary-use 
tires, whether stowed or installed on the vehicle. However, the 
Alliance recommended that the agency require the TPMS to monitor a 
matching, full-size spare tire when it is installed on the vehicle.
    The agency has decided not to require TPMS to monitor the spare 
tire, either when the tire is stowed or when it is installed on the 
vehicle, for several reasons.
    First, temporary-use tires are not intended to be used on the road 
for long periods of time. The agency also notes that compact spare 
tires pose problems for both direct and indirect TPMSs. A compact spare 
requires much a higher inflation pressure and a different warning 
threshold. A compact spare is also much smaller, and thus has a smaller 
rolling radius, than original tires. This could cause an indirect TPMS 
to give a false warning.
    Second, drivers know when a temporary-use spare tire has been 
installed on the vehicle, and they know that the tire is intended for 
temporary-use only. The agency believes that most, if not all, drivers 
will have such spare tires replaced as quickly as possible. For these 
reasons, the agency is not requiring the TPMS to monitor temporary-use 
spare tires, including compact spares and non-matching, full-size 
temporary tires.
    Notwithstanding the Alliance's comment, the agency does not believe 
that matching, full-size spare tires need be monitored, even though 
such tires may be used in the tire rotation. The agency has no data 
indicating how many vehicles are provided with a matching, full-size 
spare tire. In addition, the agency is concerned that requiring the 
TPMS to monitor the spare tire would add to the cost of the rule 
significantly because vehicle manufacturers would have to provide an 
additional pressure sensor (in the case of a direct TPMS) and a 
matching rim, with little, if any, safety benefit. Finally, the agency 
is concerned that requiring this would provide a disincentive to 
vehicle manufacturers to provide vehicles with matching, full-size 
spare tires.
g. Temperature Compensation
    In the NPRM, the agency noted that when a vehicle is being driven, 
the temperature in its tires increases. The increased temperature 
causes increases in the inflation pressure of the tires.\69\ This 
phenomenon could impact the ability of a TPMS to measure or calculate 
the cold inflation pressure in a tire accurately. A temperature 
compensation feature in a TPMS compensates for the increased inflation 
due to temperature increases.
---------------------------------------------------------------------------

    \69\ The actual tire pressure increase due to heat appears to 
depend on several factors, including whether the tire is under-
inflated to start with, the load on the tire, and how much braking 
has occurred recently. The agency believes that the maximum increase 
in tire pressure due to increased temperature is 4 psi.
---------------------------------------------------------------------------

    It is possible that, without temperature compensation, the low tire 
pressure warning telltale could be extinguished due to the increase in 
tire pressure experienced during normal driving. For instance, if a 
vehicle's tires became significantly under-inflated overnight, while 
the vehicle's tires were cold, the low tire pressure warning telltale 
would be illuminated. However, if the driver did not re-inflate the 
vehicle's tires, the temperature of the tires, and thus the inflation 
pressure, would increase during normal driving. This could cause the 
telltale to be extinguished.
    In addition, large fluctuations in the ambient temperature could 
result in the low tire pressure warning telltale's being activated on 
vehicles during ignition, and then automatically de-activated, if the 
vehicle has that capability, after the vehicle has been driven for a 
while and the temperature (and thus the pressure) in a tire increases.
    NHTSA did not propose that TPMSs have a temperature compensation 
feature. The agency believed that such a feature would add to the cost 
of the proposed standard and that indirect TPMSs would not be able to 
meet such a requirement. NHTSA did, however, request comments on 
whether such a feature should be required.
    The Alliance commented that indirect TPMSs do not require 
temperature compensation because temperature variances are accounted 
for naturally in the rolling radii of the tires. Moreover, increases in 
temperature, and thus in pressure, affect all of a vehicle's tires 
equally. Thus, the pressure in all four

[[Page 38732]]

tires increases similarly and does not affect an indirect TPMS's 
calculation of tire pressure.
    The Alliance also stated that direct TPMSs may employ temperature 
compensation to prevent nuisance warnings. The Alliance recommended 
that the agency not require temperature compensation because good 
engineering practices and concern for customer satisfaction (i.e., by 
preventing nuisance warnings) will compel this feature where needed, 
regardless of regulation.
    Advocates and the EC recommended that the agency require 
temperature compensation. Advocates stated that temperature 
compensation is crucial not only to reliable operation of TPMSs in 
providing accurate detection and notification of low pressure 
conditions in tires, but also to ensure that TPMSs provide positive 
feedback and confidence among vehicle operators as meaningful 
indicators of incipient safety problems which require rapid attention. 
Advocates expressed concerned that without temperature compensation, 
the low tire pressure warning telltale would activate and de-activate 
with temperature, and corresponding pressure, increases. Advocates 
believed this would encourage drivers to ignore the warning telltale. 
The EC suggested that temperature compensation might be necessary to 
ensure the reliability and accuracy of TPMSs.
    NHTSA has decided not to address this in this new standard. As 
noted in the Alliance comments, indirect TPMSs do not need temperature 
compensation. For direct TPMSs, the agency believes that it is 
appropriate to allow flexibility to address issues like these, 
particularly in the early stages of a technology like TPMS. If real-
world experience shows that the public is getting nuisance warnings, 
the agency will revisit this issue.
h. Low Tire Pressure Warning Telltale
    The performance requirements for the low tire pressure warning 
telltale discussed below are the same for both the four-tire, 25 
percent option and the one-tire, 30 percent option.
i. Color
    In the NPRM, the agency proposed to require that the color of the 
warning telltale be yellow. The agency received several comments on 
this issue.
    Advocates recommended that the agency require the color to be red. 
Advocates stated that a number of current lighted warning telltales 
providing status information to driver of vehicle operating systems 
(e.g., brake systems and engine oil) use red lamps. Advocates argued 
that, in most cases, an imminent safety hazard is not present when 
these warning lamps are illuminated, yet their color is red. Advocates 
also argued that the low tire pressure warning telltale would alert 
drivers about the existence of a potentially dangerous situation that 
needs rapid correction. Advocates stated that a red lamp would convey 
this urgency to drivers better than a yellow lamp.
    The Alliance agreed that yellow is the appropriate color for the 
warning telltale. However, the Alliance recommended that if a 
manufacturer chooses to imbed the warning telltale in a reconfigurable 
display, the telltale be excluded from the yellow color requirement. 
The Alliance argued that the changing appearance of the display would 
serve the purpose of drawing the driver's attention to the warning, 
which is otherwise accomplished by lighting a lamp.
    The agency is not adopting Advocates' suggestion. The use of the 
color red for telltales is usually reserved for telltales warning of an 
imminent safety hazard. The brake systems warning telltale is required 
to be red because a failure in a vehicle's brake system results in an 
imminent safety hazard that requires immediate attention. The agency 
does not believe that a significantly under-inflated tire represents an 
imminent safety hazard. As noted above, the agency has tested a variety 
of tires at 20 psi, the minimum activation pressure for the warning 
telltale, for 90 minutes. None of the tires failed. In addition, as 
noted above, the agency will propose to test all Standard Load P-metric 
tires at 20 psi under load and speed conditions for 90 minutes after 
they undergo a stringent endurance test. This proposal was included in 
the agency's NPRM to upgrade its tire standard.\70\ The agency believes 
that these tests will ensure that tires will be able to operate safely 
for at least 90 minutes at the minimum activation pressures specified 
in this standard. Moreover, the agency notes that since most Standard 
Load P-metric tires have a placard pressure of at least 30 psi, the 
warning telltale will have to illuminate at a pressure above the 
minimum activation pressure. Accordingly, the agency concludes that 
yellow is the appropriate color because it conveys the message that the 
driver can continue driving, but should check and adjust the tire 
pressure at the earliest opportunity.
---------------------------------------------------------------------------

    \70\ Docket No. NHTSA-2000-8011. The NPRM was published at 67 FR 
10049, March 5, 2002.
---------------------------------------------------------------------------

    NHTSA is also not adopting the Alliance's suggestion. The agency 
notes that reconfigurable displays can be reconfigured by the driver. 
The driver might reconfigure the display to not show the tire pressure 
for hours, days, or weeks at a time. Thus, if the low tire pressure 
warning telltale were imbedded in the reconfigurable display, the 
driver might not be alerted to the existence of a significantly under-
inflated tire. The agency has no objection if manufacturers wish to use 
a reconfigurable display to display individual tire pressure. However, 
the agency does not believe the telltale itself should be imbedded in a 
reconfigurable display.\71\ Thus, the agency is not adopting the 
Alliance's suggestion that the agency exclude reconfigurable displays 
from the color requirement.
---------------------------------------------------------------------------

    \71\ To prevent the telltale from being installed in a 
reconfigurable display, the agency is requiring that the telltale, 
once illuminated, remain illuminated until automatically 
extinguished when all of the vehicle's tires cease to be 
significantly under-inflated or until manually extinguished in 
accordance with the vehicle manufacturer's instructions.
---------------------------------------------------------------------------

ii. Symbol
    In the NPRM, the agency proposed three symbols for the low tire 
pressure warning telltale. The first was an image of the vehicle with 
lamps located at the image's tires to indicate which tire is 
significantly under-inflated. The agency noted that such an image, with 
lamps around the image that illuminate when there is a problem (e.g., 
an incompletely closed door) in that area, is already built into the 
dashboard of some vehicles. Thus, the agency proposed that this image, 
with lamps at the image's tires to indicate which tire is significantly 
under-inflated, be required if a vehicle manufacturer provides a 
display that identifies which tire is significantly under-inflated.
    The agency received no comments opposing the use of this image. 
Thus, the final rule requires the use of this image, with lamps at the 
image's tires to indicate which tire is significantly under-inflated, 
if a vehicle manufacturer provides a display that identifies which tire 
is significantly under-inflated.
    In addition to the vehicle image, the agency proposed a choice 
between two symbols for TPMSs that do not inform the driver which tire 
is significantly under-inflated. The first was developed by the 
International Organization for Standardization (ISO). It is used to 
identify tire malfunctioning and is currently used in some vehicles 
with TPMSs. The second was a symbol of a low tire developed by the 
agency. All three symbols are set out below:

BILLING CODE 4910-59-P

[[Page 38733]]

[GRAPHIC] [TIFF OMITTED] TR05JN02.000

BILLING CODE 4910-59-C

[[Page 38734]]

    Prior to issuing the NPRM, the agency conducted symbol 
comprehension tests to aid the agency in determining which symbol best 
conveyed a tire pressure problem to drivers. The agency asked 120 
people to look at 15 symbols, including the ISO symbol and the low tire 
symbol developed by the agency, and fill in the blank in the following 
statement: ``This image has just appeared on your vehicle's dashboard. 
It is a warning for ___.''
    Results of this test indicated that the ISO symbol was the least 
understood among the 15 symbols, with a comprehension rate of only 38 
percent. The low tire symbol developed by the agency had a 
comprehension rate of 100 percent.
    The agency received several comments on this issue. Advocates and 
ITRA recommended that NHTSA require the low tire symbol developed by 
the agency because it had high recognition value, while the ISO symbol 
had low recognition value.
    The Alliance recommended that the agency require the ISO symbol for 
several reasons. First, the Alliance argued that while the agency-
developed low tire symbol is easier to recognize than the ISO symbol on 
paper, it is not easier to recognize when reduced to the size, and 
placed in the medium, that would be used for a dashboard display.\72\ 
The Alliance claimed that on a dashboard display, the resolution of the 
low tire symbol would not allow for the flat portion of the tire to be 
seen. The ISO symbol, according to the Alliance, remains visible and 
recognizable, even when reduced and placed in a dashboard.
---------------------------------------------------------------------------

    \72\ In the symbol comprehension tests, the symbols were 
presented on paper as 18 x 18 mm images. The telltales in vehicle 
dashboards average about 8 x 8 mm.
---------------------------------------------------------------------------

    Second, the Alliance argued that the low tire symbol falsely 
indicates that a tire is flat, rather than that pressure is low. The 
ISO symbol does not provide this misleading information.
    Third, the Alliance argued that while the ISO symbol initially may 
not be recognized as a low tire warning, the near-universal requirement 
for TPMSs will rapidly lead to widespread recognition of whatever 
symbol NHTSA ultimately decides to require.
    Finally, the Alliance argued that the ISO symbol has already been 
adopted as a voluntary standard and is in widespread use among those 
manufacturers currently offering TPMSs. Were NHTSA to require a unique 
symbol for the U.S. market, manufacturers who already use the ISO 
symbol would be required to re-tool their instrument clusters to 
accommodate the unique symbol. According to the Alliance, this would be 
expensive and time-consuming.
    ITRA recommended that the agency require an audible warning as well 
as a warning lamp. ITRA stated that many drivers ignore a warning lamp, 
especially on bright days.
    The agency agrees with the Alliance's arguments. Although the 
NHTSA-developed low tire symbol had a high recognition rate on paper, 
its level of detail, and thus its recognition rate, might not be 
retained when reduced in size and translated from paper to a dashboard 
display. Moreover, the agency believes that when TPMSs are first 
introduced, no matter what symbol the agency requires, drivers will 
consult their owner's manual to determine exactly what the symbol means 
and what they should do when the telltale illuminates. Drivers then 
will associate that telltale with a significantly under-inflated tire. 
Finally, the agency is interested in harmonizing its standards when it 
can do so consistent with the interests of safety. Since the ISO symbol 
is currently being used by manufacturers in Europe and the U.S., and 
since it will likely be readily learned, the agency can easily 
harmonize this requirement. For these reasons, the agency is requiring 
the ISO symbol. The agency also has decided to allow the use of the 
words ``Low Tire'' with the ISO symbol so that drivers will become 
familiar with the low tire pressure warning telltale more rapidly.
    The agency is not requiring an audible warning in addition to the 
telltale lamp. The agency notes that although ITRA stated that many 
drivers ignore a warning lamp, it provided no such evidence. The agency 
believes that requiring an audible warning would increase the cost of 
TPMSs without providing any additional benefits.
iii. Self-Check
    In the NPRM, the agency did not propose that the TPMS conduct a 
self-check or a bulb-check at vehicle start-up. However, it did request 
comments on the desirability of requiring such a check.
    Advocates strongly supported both a system-check and a bulb-check. 
Advocates stated that vehicle systems regularly provide a system 
readiness check or a bulb-check to provide an initial indication to the 
driver that the system is operational. Advocates recommended a system- 
and bulb-check which provides several seconds of separate notification 
to the driver after the vehicle is started instead of the fleeting 
notification which is usually supplied only when the ignition is first 
engaged.
    RMA also supported both a system-check and a bulb-check. RMA argued 
that, with the broad installation of TPMSs, much of the motoring public 
will rely heavily on the systems for tire inflation maintenance. The 
frequency of routinely checking tire pressure is expected to drop 
significantly. Accordingly, RMA recommended that TPMSs go through a 
self-diagnostic check, including a bulb-check, with each vehicle start-
up to indicate to the driver that the system is operational.
    TRW stated that both direct and indirect TPMSs could perform a 
bulb-check and a self-check. TRW stated that with direct TPMSs, each 
tire pressure sensor can be set to periodically transmit an indication 
that it is functioning. If a sensor is not transmitting, or a sensor's 
battery is low, the receiver can send a system-malfunction message to 
the vehicle's body control module and illuminate the TPMS telltale. If 
the telltale is not illuminated, the driver is being told that the TPMS 
is functioning properly and no tire is significantly under-inflated. 
TRW stated that, for indirect TPMSs, the ABS system already performs a 
system malfunction monitoring process. This includes both static and 
dynamic checks that are handled in a continuous monitoring process.
    The Alliance recommended that the agency not require either a bulb-
check or a self-check. The Alliance stated that vehicle manufacturers 
include serviceability provisions as a matter of normal design practice 
and do not need regulatory requirements in this regard.
    After considering all the comments on this issue, the agency has 
decided to require a bulb-check, but not a self-check, at vehicle 
start-up. The agency believes that a bulb-check will add little, if 
any, cost to the TPMS and provide drivers with useful information, 
i.e., that the warning telltale bulb is functional.\73\ Accordingly, 
the agency is adding a new section S4.3.3 as follows:
---------------------------------------------------------------------------

    \73\ The agency did not quantify the cost of a bulb-check, but 
the agency notes that most of the TPMSs tested by the VRTC performed 
a bulb-check. Since the agency used these systems in estimating the 
costs of this rulemaking, the cost of a bulb-check likely was 
already included, e.g., in the cost of the control module.

    S4.3.3 (a) Except as provided in paragraph (b) of this section, 
each low tire pressure warning telltale must be activated as a check 
of lamp function either when the key locking system is turned to the 
``On'' (``Run'') position when the engine is not running, or when 
the key locking system is in a position between ``On'' (``Run'') and 
``Start'' that is designated by the manufacturer as a check 
position.

[[Page 38735]]

    (b) The low tire pressure warning telltale need not be activated 
when a starter interlock is in operation.

    The agency has decided not to require that the TPMS perform a self-
check. The agency agrees with RMA's comment that drivers will rely on 
the TPMS for tire inflation maintenance and check their tire pressure 
less often. However, NHTSA only requires a self-check for air bag and 
brake systems, i.e., major safety systems. Moreover, the agency is 
uncertain of the costs and benefits of requiring a self-check.\74\ 
According to TPMS manufacturer comments, the TPMSs in service to date 
have shown outstanding reliability, so there appears to be little need 
for a requirement in this area.
---------------------------------------------------------------------------

    \74\ The cost of a self-check for air bag and brake systems was 
included in the cost of the electronic control units for those 
systems. The agency was unable to separately estimate the cost of a 
self-check for those systems. Similarly, in its tear-down study of 
TPMSs to estimate their costs, the agency was unable to separately 
estimate the cost of a self-check for TPMSs.
---------------------------------------------------------------------------

i. General Written Instructions for All TPMSs
    In the NPRM, the agency proposed that the vehicle owner's manual 
provide an image of the TPMS warning telltale and the following 
information, in English:

    When the TPMS warning light is lit, one of your tires is 
significantly under-inflated. You should stop and check your tires 
as soon as possible, and inflate them to the proper pressure as 
indicated on the vehicle's tire inflation placard. Driving on an 
under-inflated tire causes the tire to overheat and can eventually 
lead to tire failure. Under-inflation also reduces fuel efficiency 
and tire tread life, and may affect the vehicle's handling and 
stopping ability.

    The agency also proposed to allow each vehicle manufacturer, at its 
discretion, to provide additional information about the significance of 
the low tire pressure warning telltale and description of corrective 
action that should be undertaken.
    The Alliance stated that it was not opposed to the language the 
agency proposed. However, the Alliance recommended that the agency 
include additional language addressing inherent system limitations, 
owner/driver responsibility, and replacement tires and rims. The 
Alliance did not recommend any specific language.
    Advocates recommended that the agency change the first sentence to 
read: ``When the TPMS warning light is lit, one or more of your tires 
are seriously under-inflated.'' Advocates also recommended that the 
agency remove the word ``eventually'' from the third sentence to 
encourage drivers to take immediate action.
    RMA recommended that the written instructions be revised to read as 
follows:

    When the TPMS warning light is lit, one of your tires is 
significantly under-inflated. You should stop and check your tires 
as soon as possible, and inflate them to the proper pressure as 
indicated on the vehicle's tire inflation placard. If checking air 
pressure when the tire is hot from driving, never ``bleed'' or 
reduce air pressure, as it is normal for pressures to increase above 
recommended cold pressures. Driving on a significantly under-
inflated tire causes the tire to overheat and can eventually lead to 
tire failure. Under-inflation also reduces fuel efficiency and tire 
tread life, and may affect the vehicle's handling and stopping 
ability. Each tire, including the spare, should be checked monthly 
when cold and set to the recommended inflation pressure as specified 
on the vehicle placard and owner's manual.

    The agency is accepting Advocates' recommendation to add the words 
``or more'' to the first sentence and remove the word ``eventually'' 
from the third sentence. The agency notes that activation of the low 
tire pressure warning telltale could signify that more than one tire is 
significantly under-inflated. The agency also notes that the word 
``eventually'' could lead drivers to believe that a significantly 
under-inflated tire is not a potentially dangerous condition.
    The agency also is accepting the last sentence of RMA's recommended 
instructions. The agency has no objection to this information being 
added and believes it may be useful in encouraging drivers to check 
their tire pressure more often.
    The agency is not adopting Advocates' recommendation to change the 
word ``significantly'' in the first sentence to ``seriously.'' The 
standard does not define either term. However, Section 13 of the TREAD 
Act refers to ``significant'' rather than ``serious'' under-inflation. 
Moreover, in the NPRM the agency discussed ``significant'' rather than 
``serious'' under-inflation. For the sake of consistency, the agency 
believes the phrase ``significantly under-inflated'' should be used in 
the written instructions. The agency also is not adopting the third 
sentence of RMA's recommended language. The agency notes that if the 
low tire pressure warning telltale is lit, then one or more of the 
vehicle's tires is significantly under-inflated. The agency does not 
believe that drivers will respond to the warning telltale by reducing 
air pressure. Thus, that sentence is unnecessary.
    As noted above, the agency is accepting the Alliance's 
recommendation to add language concerning the inherent limitations of 
TPMSs. The agency specified the additional information vehicles 
certified to the one-tire, 30 percent compliance option must include in 
the owner's manual. That information must follow the general written 
instructions specified below.
    As for the Alliance's recommendation for additional language on 
driver responsibility and replacement tires, the agency is allowing 
manufacturers, at their discretion, to add additional information 
regarding the particular TPMS installed in the vehicle. This should 
allow manufacturers to add information concerning the limitations of 
the particular TPMS, driver responsibility, replacement tires, whether 
the TPMS works with the vehicle's spare tire, and how to use the reset 
button, if one is provided. However, any additional language should be 
placed after the written instructions the agency is requiring. The 
written instructions specified by the agency should be placed in the 
owner's manual, in English, as specified below:

    When the TPMS warning light is lit, one or more of your tires is 
significantly under-inflated. You should stop and check your tires 
as soon as possible, and inflate them to the proper pressure as 
indicated on the vehicle's tire information placard. 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. Each tire, including the spare, 
should be checked monthly when cold and set to the recommended 
inflation pressure as specified in the vehicle placard and owner's 
manual.

j. Test Conditions
    In the NPRM, the agency proposed that each vehicle be tested at its 
GVWR and its lightly loaded vehicle weight (LLVW), defined as unloaded 
vehicle weight plus up to 400 pounds (including test driver and 
instrumentation). The ambient temperature would be between 0 degrees C 
(32 degrees F) and 40 degrees C (104 degrees F). The test road surface 
would be dry and smooth. The vehicle would be tested at speeds between 
50 km/h (31.1 mph) and 100 km/h (62.2 mph).
    Advocates supported these proposed test conditions. RMA recommended 
that vehicles be tested at speeds up to 120 km/h (75 mph) to reflect 
real-world driving conditions. RMA argued that drivers typically travel 
on interstate highways at speeds of 75 mph and higher for extended 
periods of time. Thus, TPMSs should be tested to ensure

[[Page 38736]]

that they function properly at highway speeds.
    The Alliance recommended several changes to the proposed test 
conditions. The Alliance recommended separate test conditions for 
direct and indirect TPMSs as follows:
    Test Conditions for Indirect TPMS:
    S5.1  Ambient temperature. The ambient temperature is between 
0 deg.C (32 deg.F) and 40 deg.C (104 deg.F). The ambient temperature 
during the test procedure must not change more than +/-1.5 deg.C (+/
-2.5 deg.F).
    S5.2  Road test surface.
    S5.2.1  Test Surface Description. Tests are conducted on a dry, 
smooth level roadway.
    S5.2.2  Radius of Curvature. Minimum radius of curvature of 1600 
mm.
    S5.2.3  Longitudinal Acceleration. Maximum longitudinal 
acceleration generated +/-0.05 g at the test speeds indicated.
    S5.2.4  Gradient. The test surface has no more than a 1% gradient 
in the direction of testing and no more than a 2% gradient 
perpendicular to the direction of testing.
    S5.2.5  Pavement Friction. The road test surface produces a peak 
friction of coefficient of 0.9 when measured using an American Society 
of Testing Materials (ASTM) E1136 standard reference test tire, in 
accordance with ASTM Method E 1337-90, at a speed of 64.4 km/h (40 
mph), without water delivery.
    S5.3  Altitude. Tests are conducted at an altitude between 0 to 500 
m (0 to 1640 ft) above sea level.
    S5.4  Vehicle conditions.
    S5.4.1  Test weight. The vehicle is tested at its lightly loaded 
vehicle weight and at its gross vehicle weight rating without exceeding 
any of its gross axle weight ratings. The weights should also be evenly 
distributed between the left and right sides. The difference between 
the left and right side static corner weights should be less than 3% of 
the total vehicle weight.
    S5.4.2  Vehicle speed. The vehicle is tested at a speed between 50 
km/h (31.1 mph) and 100 km/h (62.2 mph).
    Test Conditions for Direct TPMSs:
    The Alliance's recommended test conditions for direct TPMSs are the 
same as those for indirect TPMSs, with the following additions:
    S5.4  Barometric Pressure. Barometric Pressure will be recorded and 
the measured significantly under-inflated tire pressure threshold will 
be corrected using the following equation: P (adjusted threshold) = P 
(significantly under-inflated) = 1 Atmosphere - Barometric Pressure. 
Note: 1 atmosphere = 101.3kpa (14.7 psi).
    NHTSA is not adopting the additional conditions recommended by the 
Alliance. The agency notes that specifications regarding radius of 
curvature, longitudinal acceleration, gradient, and pavement friction 
are useful in braking tests, but have little relevance to the testing 
of TPMSs. The agency also notes that changes in altitude and barometric 
pressure should make little difference, if any, in the outcome of these 
tests. The agency also does not see the need to specify that the 
vehicle weights should be evenly distributed and that the difference 
between the left and right side static corner should be less than 3 
percent of the total vehicle weight. NHTSA does not specify this for 
braking or any other tests that need a high degree of precision and 
specificity.
    NHTSA also is not adopting RMA's recommended test speed. While 
passenger vehicles are regularly driven on interstate highways at 
speeds of 75 mph, those vehicles are also regularly driven at even 
higher speeds. The point of the test speeds is not to test the speed 
capability of the vehicle. Instead, the test speeds must cover a 
sufficient variety of driving speeds to reflect real-world usage. The 
agency believes that the proposed test speeds do that.
    NHTSA has decided to revise the definition of ``lightly loaded 
vehicle weight'' to make it consistent with Standard No. 135, 
``Passenger car brake systems.'' The definition now reads as follows:

    Lightly loaded vehicle weight means unloaded vehicle weight plus 
the weight of a mass of 180 kg (396 pounds), including test driver 
and instrumentation.

    These test conditions are the same for both the four-tire, 25 
percent and one-tire, 30 percent compliance options.
k. Test Procedures
    In the NPRM, the agency proposed that the vehicle's tires be 
inflated to the placard pressure. Then the vehicle would be driven 
between 50 km/h (31.1 mph) and 100 km/h (62.2 mph) for up to 20 
minutes. While driving at that speed, any combination of tires (from 
one to four for the first alternative and from one to three for the 
second) would be deflated until it was significantly under-inflated. 
Then the elapsed time between the time that the vehicle's tire or 
combination of tires became significantly under-inflated and the time 
the low tire pressure warning telltale was illuminated would be 
recorded. After the telltale illuminates, pressure would be added to 
the tire or combination of tires that was deflated such that the tire 
or each of the tires was one psi below the level of significant under-
inflation. Then the warning telltale would be checked to see if it 
remained illuminated. If the telltale remained illuminated, a manual 
reset would be attempted. These test procedures were to be repeated for 
each tire and rim combination recommended for the vehicle by the 
vehicle manufacturer.
    The Alliance claimed that the proposed test procedures would not 
allow for fair and adequate assessments of both direct and indirect 
TPMS performance. The Alliance recommended separate test procedures for 
indirect and direct TPMSs as follows:
    Test Procedures for Indirect TPMSs:
    (a) Inflate the vehicle's tires to the vehicle manufacturer's 
recommended cold inflation pressure.
    (b) If applicable, initiate a TPMS reset and calibration using the 
specified vehicle manufacturer's instructions. Record all the tire 
pressure values.
    (c) While driving within the speed range specified in paragraph 
S5.4.2 of this standard, deflate any single tire at a rate of 10 kPa/
min +/-5 kPa/min (1.5 psi/min +/-0.7 psi/min) until that tire is 
significantly under-inflated.
    (d) Continue to drive within the speed range specified in paragraph 
S5.4.2 of this standard. Monitor the tire pressures and adjust 
pressures (if necessary) to remain significantly under-inflated. Record 
the elapsed time and cumulative driving distance at a constant speed 
(maximum longitudinal acceleration  +/-0.05 g) and straight (lateral 
acceleration  +/-0.05 g) until the low tire pressure warning telltale 
is illuminated or 10 miles of straight, constant speed driving has 
accumulated, whichever happens first.
    (e) Turn the ignition off and let the vehicle sit for 5 minutes. 
Turn the key back on to confirm that the warning telltale re-
illuminates. If the warning telltale does not re-illuminate, repeat 
step 6(d) to verify that the warning telltale does re-illuminate. This 
completes the test.
    (f) To test a single tire deflation at other tire locations on the 
vehicle using the same tire and rim combination:
    (1) Record all the tire pressure values and re-inflate the low tire 
to the matching tire on the opposite side of the same axle.
    (2) Initiate a system reset of the warning telltale per the 
manufacturer's instructions.
    (3) Repeat steps S6(b) through (e).
    (g) To test a single tire deflation using another tire and rim 
combination, which is recommended by the vehicle

[[Page 38737]]

manufacturer, repeat steps 6(a) through (e).
    Test Procedures for Direct TPMSs:
    (a) Inflate the vehicle's tires to the vehicle manufacturer's 
recommended cold inflation pressure.
    (b) If applicable, initiate a TPMS reset. Drive the vehicle to 
precondition the tires using the specified vehicle manufacturer's 
instructions. Record all the tire pressure values.
    (c) While driving within the speed range specified in paragraph 
S5.4.2 of this standard, deflate any tire or combination of tires at a 
rate of 10 kPa/min +/-5 kPa/min (1.5 psi/min +/-0.7 psi/min) until the 
tire(s) is (are) significantly under-inflated to threshold P (adjusted 
threshold).
    (d) Continue to drive within the speed range specified in paragraph 
S5.4.2 of this standard. Monitor the tire pressures and adjust 
pressures (if necessary) to remain significantly under-inflated. Record 
the elapsed time and cumulative driving distance at a constant speed 
(maximum longitudinal acceleration  +/-0.05 g) and straight (lateral 
acceleration  +/-0.05 g) until the low tire pressure warning telltale 
is illuminated or 10 miles of straight, constant speed driving has 
accumulated, whichever happens first.
    (e) Turn the ignition off and let the vehicle sit for 5 minutes. 
Turn the key back on to confirm that the warning telltale re-
illuminates. If the warning telltale does not re-illuminate, repeat 
step 6(d) to verify that the warning telltale does re-illuminate. This 
completes the test.
    (f) To test other combinations of tire deflations for this tire and 
rim combination:
    (1) Re-inflate the tires to the tire pressure value recorded in 
step S6(b).
    (2) Initiate a system reset of the warning telltale per the 
manufacturer's instructions.
    (3) Repeat steps S6(b) through (e).
    (g) To test a single tire deflation using another tire and rim 
combination, which is recommended by the vehicle manufacturer, reset 
the warning telltale per the manufacturer's instructions and repeat 
steps 6(a) through (e).
    NHTSA is not adopting the Alliance's recommended test procedures. 
The agency believes that the test procedures contained in this final 
rule adequately test both direct and indirect TPMSs under conditions 
similar to real-world conditions. The test procedures are as follows:
    S6. Test procedures.
    (a) Inflate the vehicle's tires to the vehicle manufacturer's 
recommended cold inflation pressure for the applicable vehicle load 
conditions specified in paragraph S5.3.1 of this standard. If the 
vehicle manufacturer has not recommended an inflation pressure for the 
lightly loaded condition, the inflation pressure specified by the 
vehicle manufacturer for the gross vehicle weight rating is used.
    (b) With the vehicle stationary and the key locking system in the 
``Lock'' or ``Off'' position, turn the key locking system to the ``On'' 
or ``Run'' position. The tire pressure monitoring system must perform a 
check of telltale lamp function as specified in paragraph S4.3.3 of 
this standard.
    (c) If applicable, reset the tire pressure monitoring system in 
accordance with the instructions specified in the vehicle owner's 
manual.
    (d) Drive the vehicle at any speed specified in paragraph S5.3.2 of 
this standard for 20 minutes.
    (e)(1) For vehicles complying with S4.2.1, 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 low 
tire pressure monitoring system is required to activate the low tire 
pressure warning telltale for that vehicle.
    (2) For vehicles complying with S4.2.2, stop the vehicle \75\ and 
deflate any one tire until the deflated tire is at 7 kPa (1 psi) below 
the inflation pressure at which the low tire pressure monitoring system 
is required to activate the low tire pressure warning telltale for that 
vehicle.
---------------------------------------------------------------------------

    \75\ Upon stopping the vehicle, the agency may deflate the 
tire(s) immediately or wait until the tire(s) cool to the ambient 
temperature, or any time in between, e.g., when the tire(s) reach 
their original cold inflation pressure. The agency recognizes that 
deflating the tires while they are still hot would be a less 
stringent test than if the tires were allowed to cool down before 
being deflated. All vehicles must comply when the tires are warm or 
cold.
---------------------------------------------------------------------------

    (f) Drive the vehicle at any speed specified in paragraph S5.3.2 of 
this standard. Record the time from when the vehicle speed reaches 50 
km/h until the time the low tire pressure warning telltale illuminates. 
The telltale must illuminate within 10 minutes as required in paragraph 
S4.2.1(a) or S4.2.2(a) of this standard.
    (g) Stop the vehicle and turn the key locking system to the ``Off'' 
or ``Lock'' position. After a 5-minute period, turn the vehicle's key 
locking system to the ``On'' or ``Run'' position. The telltale must 
remain illuminated.
    (h) Keep the vehicle stationary for a period of one hour.
    (i) Inflate all of the vehicle's tires to the vehicle 
manufacturer's recommended cold inflation pressure. If the vehicle's 
tire pressure monitoring system has a manual reset feature, reset the 
system in accordance with the instructions specified in the vehicle 
owner's manual.
    (j) Drive the vehicle at any speed specified in paragraph S5.3.2 of 
this standard. The telltale must extinguish as specified in paragraph 
S4.2.1(b) or S4.2.2(b).
    (k)(1) For vehicles complying with S4.2.1, if additional 
combinations of tires are tested, repeat the test procedures in 
paragraphs S6(a) through (j).
    (2) For vehicles complying with S4.2.2, if the other individual 
tires are tested, repeat the test procedures in paragraphs S6(a) 
through (j).
    (l) Utilizing the existing vehicle rims, repeat the test procedures 
in paragraphs S6(a) through (k) for each tire size recommended for the 
vehicle by the vehicle manufacturer. Note: If a different rim size is 
required, OEM rim and tire assemblies appropriate for the tire pressure 
monitoring system are used for testing.
    The test procedures recommended by the Alliance are similar to the 
procedures the agency is specifying in this final rule. The agency 
notes that separate test procedures for the two compliance options are 
necessary because the performance requirements are different for each 
option. For example, the agency must be able to test multiple 
combinations of under-inflated tires, including all four tires, when 
testing vehicles that are certified to the four-tire, 25 percent 
option.
6. Lead Time
    In the NPRM, the agency noted that the TREAD Act requires that the 
agency publish this final rule by November 1, 2001, and that the final 
rule take effect not more than two years after the final rule. The 
agency was concerned that TPMS manufacturers would not have the 
production capacity to supply TPMSs to equip 16 million vehicles 
annually, and that vehicle manufacturers would not have adequate time 
to develop TPMSs for all their vehicle applications. Thus, the agency 
indicated that it would consider a phase-in with a compliance schedule 
of 35 percent for the first year (2003), 65 percent the second year, 
and 100 percent in the third year.
    No commenter opposed a phase-in of the TPMS requirements for light 
vehicles.
    The Alliance stated that the phase-in proposed by the agency is too 
aggressive to allow for orderly and cost-effective implementation of 
the requirements. The Alliance stated that the agency

[[Page 38738]]

phase-in would jeopardize vehicle development programs, which allow for 
sufficient ``prove-out'' and implementation of new technology. The 
Alliance argued that TPMS technology is still relatively new and needs 
to be properly proved-out to avoid customer complaints and/or recalls.
    For these reasons, the Alliance recommended a four-year phase-in as 
follows: 15 percent of a manufacturer's affected products to be 
equipped with a semi- or fully-compliant TPMS in the first year; 35 
percent in the second year; and 70 percent in the third year; and, in 
the final year, 100 percent of a manufacturer's affected products to be 
equipped with a fully-compliant TPMS.The Alliance noted that a semi-
compliant TPMS is one that meets all but specified interface 
requirements, and would only be allowed during the phase-in period but 
not in the final year of the phase-in. The Alliance claimed that 
allowing semi-compliant TPMSs during the phase-in would reduce the cost 
of compliance considerably, as cluster and display alterations are very 
expensive and require a long lead time to implement. Delaying these 
interface requirements would allow manufacturers who have already 
designed and/or implemented TPMSs to receive credit for those systems 
before and during the phase-in.
    The agency agrees with the Alliance's comments about the pace of 
the phase-in. TPMS technology is still relatively new. While it has 
been used on a few high-end models for several years, it has not been 
widely implemented. Moreover, the agency remains concerned that TPMS 
manufacturers will not be able to produce enough systems and parts to 
supply 16 million vehicles annually.
    Accordingly, the agency is implementing a four-year phase-in period 
as follows: 10 percent of a vehicle manufacturer's affected vehicles 
must be equipped with a TPMS that complies with either the four-tire, 
25 percent or the one-tire, 30 percent option in the first year (i.e., 
November 1, 2003 to October 31, 2004); 35 percent in the second year 
(i.e., November 1, 2004 to October 31, 2005); 65 percent in the third 
year (i.e., November 1, 2005 to October 31, 2006). After October 31, 
2006, 100 percent of a vehicle manufacturer's affected vehicles must be 
equipped with a TPMS that complies with the requirements set forth in 
the second part of this final rule. As noted above, the agency will 
publish the second part of this final rule by March 1, 2005, in order 
to give manufacturers sufficient lead time.
    The agency believes this phase-in period allows for a sufficient 
prove-out of TPMS technology before widespread implementation in the 
first two years, followed by the last two years of aggressive 
implementation. The agency notes that the final rule requires fewer 
vehicles to comply in the first year of the phase-in (10 percent) than 
the Alliance recommended (15 percent). NHTSA is lowering the number of 
vehicles that will have to comply because the agency was unable to meet 
the statutory deadline of November 1, 2001.
    NHTSA also notes that since the agency is permitting manufacturers 
to comply with the one-tire, 30 percent option until at least October 
31, 2006, manufacturers will be able to comply with current indirect 
TPMSs while working to improve the performance of indirect TPMSs.
    The agency is allowing carry-forward credits, but only for vehicles 
that are manufactured during the phase-in and comply with the four-
tire, 25 percent option of the first part of this final rule. Vehicles 
that comply with the one-tire, 30 percent option cannot be counted for 
purposes of carry-forward credits.
    While the agency is not adopting the Alliance's particular 
recommendation to allow semi-compliant TPMSs during the phase-in, it 
has decided to allow compliance with an alternative set of requirements 
during that period. The agency believes the addition of the one-tire, 
30 percent option to the first part of this final rule will provide 
ample time for manufacturers to complete any development needed to 
enable them to install either direct, improved indirect, or hybrid 
TPMSs in their vehicles by the time the second part of this final rule 
takes effect on November 1, 2006.
    The agency is adopting VSC's suggestion that the agency give small 
volume manufacturers until the end of the phase-in period to comply 
with the TPMS requirements. The agency has done this in the past when 
implementing a major rule.
    As with previous phase-ins, NHTSA is adopting reporting 
requirements to monitor the implementation of the phase-in. The agency 
is including the reporting requirements in 49 CFR Part 590, which 
currently specifies back door latch, hinge, and lock phase-in reporting 
requirements. Since the phase-in currently addressed by Part 590 was 
completed December 31, 1999, the agency is replacing the existing 
language with regulatory text addressing the phase-in of Standard No. 
138's requirements for TPMS.

C. Study of Effects of TPMSs That Do Not Meet a Four-Tire, 25 Percent 
Under-Inflation Requirement

    To help provide additional data on the performance and 
effectiveness of TPMSs, NHTSA plans to conduct a study comparing the 
tire pressures of vehicles without a TPMS to the tire pressures of 
vehicles equipped with a TPMS that does not meet a four-tire, 25 
percent compliance option. The agency will arrange for a peer review of 
the study methodology and of the study results, including the safety 
significance of any differences in tire pressure between the two groups 
of vehicles. If sufficient data are available, the agency also will 
assess the performance and effectiveness of TPMSs that do meet a four-
tire, 25 percent option. The study, which will be completed by March 1, 
2004, has the following two purposes.
1. Effect on Tire Pressure
    The study will give the agency additional information regarding the 
extent to which vehicles equipped with a TPMS that does not meet a 
four-tire, 25 percent option have tire pressures closer to the 
vehicle's manufacturer's recommended inflation pressure than vehicles 
without a TPMS.
2. Effect on Number of Significantly Under-Inflated Tires
    The study also will give the agency additional information 
regarding the extent to which vehicles equipped with a TPMS that does 
not meet a four-tire, 25 percent option have fewer significantly under-
inflated tires than vehicles without a TPMS.

D. Part Two of the Final Rule--November 2006 and Thereafter

    Based on the record compiled to this date, the results of the 
study, and any other new information (including, for example, 
information on the overall safety benefits of ABS) submitted to the 
agency, NHTSA will issue the second part of this final rule. The second 
part will be issued by March 1, 2005, to ensure vehicle manufacturers 
have sufficient lead time before November 1, 2006, when all new light 
vehicles must be equipped with a TPMS.
    Based on the record now before the agency, NHTSA tentatively 
believes that a four-tire, 25 percent requirement would best meet the 
TPMS mandate in the TREAD Act. Nevertheless, it is possible that the 
new information may be sufficient to justify a continuation of the 
requirements in the first part of this final rule, or even some other 
alternative.

[[Page 38739]]

VIII. Benefits

    Following is a summary of the benefits associated with this final 
rule. For a more detailed analysis, see the agency's Final Economic 
Assessment (FEA). A copy of the FEA has been placed in the docket. In 
the following discussion, the agency analyzes the benefits and costs of 
both the four-tire, 25 percent and one-tire, 30 percent options.
    For purposes of this analysis, the agency assumes that 95 percent 
of drivers will respond to a low tire pressure warning by re-inflating 
their tires to the placard pressure. OMB questioned this assumption in 
its return letter. NHTSA has little hard evidence supporting this 
assumption. As discussed in the FEA, a recent study indicated that 97 
percent of respondents stated they would respond to a dashboard warning 
light informing them that their tire pressure was low.\76\ However, the 
agency has some concerns, such as the sample of respondents and the 
question format, with this study. The agency has attempted to find 
other studies with data on response rates to similar warning lights, 
but has been unable to do so.
---------------------------------------------------------------------------

    \76\ ``Examining the Need for Cycloid's Pump: An Analysis of 
Attitudes and a Study of Tire Pressure and Temperature 
Relationships,'' University of Pittsburgh, Departments of Mechanical 
and Industrial Engineering, December 7, 2001. A copy of this study 
has been placed in the docket. (Docket No. NHTSA-2000-8572-209.
---------------------------------------------------------------------------

    However, as part of the new study to be completed by March 1, 2004, 
the agency plans to ask owners of vehicles equipped with a TPMS whether 
their low tire pressure telltale has ever illuminated, and, if so, how 
they reacted to it. This should provide useful data for the agency's 
decision on the requirements for the second part of this final rule.
    Under-inflation affects many different types of crashes. These 
include crashes which result from:
    (1) Skidding and/or losing control of the vehicle in a curve, such 
as a highway off-ramp, or in a lane-change maneuver;
    (2) hydroplaning on a wet surface, which can cause increases in 
stopping distance and skidding or loss of control;
    (3) increases in stopping distance; and
    (4) flat tires and blowouts; and
    (5) overloading the vehicle.
    The agency was able to identify target populations for skidding and 
loss of control crashes, stopping distance (which involves any vehicle 
that brakes during a crash sequence), flat tires, and blowouts. The 
agency was not able to identify, from crash files and other reports, a 
target population for crashes caused by hydroplaning and overloading 
the vehicle.

A. Tire Safety Benefits

1. Skidding/Loss of Control
    Under-inflation reduces tire stiffness, which causes the tire to 
generate lower cornering force. When a tire is under-inflated, the 
vehicle requires a greater steering angle to generate the same 
cornering force in a curve or in a lane-change maneuver. This can 
result in skidding or loss of control of the vehicle in a tight curve 
or a quick lane-change maneuver.
    The agency estimates that if all light vehicles meet the four-tire, 
25 percent compliance option, 46 fatalities will be prevented and 4,345 
injuries will be prevented or reduced in severity per year due to 
reductions in these types of crashes. If all light vehicles meet the 
one-tire, 30 percent compliance option, 30 fatalities will be prevented 
and 2,817 injuries will be prevented or reduced in severity per year 
due to reductions in these types of crashes.
2. Stopping Distance
    As explained in greater detail above in section III.D.1., ``Reduced 
Vehicle Safety--Tire Failures and Increases in Stopping Distance,'' 
tires are designed to maximize their performance capabilities at a 
specific inflation pressure. When a tire is under-inflated, the shape 
of its footprint and the pressure it exerts on the road surface are 
both altered. This degrades the tire's ability to transmit braking 
force to the road surface, and increases a vehicle's stopping distance, 
especially on wet surfaces.
    Decreasing stopping distance is beneficial in several ways. Some 
crashes can be completely avoided. Other crashes will still occur, but 
at a lower impact speed because the vehicle is able to decelerate more 
quickly.\77\
---------------------------------------------------------------------------

    \77\ The FEA divides the benefits from reductions in stopping 
distance into fatalities and injuries reduced as a result of 
reductions in crashes on dry surfaces and on wet surfaces. As noted 
above, under-inflated tires have a greater impact on stopping 
distance when a vehicle is on a wet surface than when a vehicle is 
on a dry surface. However, most crashes occur on dry surfaces. Thus, 
the agency estimates that more fatalities and injuries will be 
reduced as a result of reductions in crashes that occur on dry 
surfaces than crashes that occur on wet surfaces.
---------------------------------------------------------------------------

    The agency estimates that if all light vehicles meet the four-tire, 
25 percent compliance option, 39 fatalities will be prevented and 3,410 
injuries will be prevented or reduced in severity per year due to 
reductions in vehicles' stopping distances. If all light vehicles meet 
the one-tire, 30 percent compliance option, 17 fatalities will be 
prevented and 1,562 injuries will be prevented or reduced in severity 
per year due to reductions in vehicles' stopping distances.
3. Flat Tires and Blowouts
    Under-inflation, along with high speed and overloading, can cause 
tire blowouts. A blowout in one of the front tires can cause the 
vehicle to veer off the road or into oncoming traffic. A blowout in one 
of the rear tires can cause spinning and loss of control of the 
vehicle.
    The agency estimates that if all light vehicles meet the four-tire, 
25 percent compliance option, 39 fatalities will be prevented and 967 
injuries will be prevented or reduced in severity per year due to 
reductions in crashes involving blowouts and flat tires. If all light 
vehicles meet the one-tire, 30 percent compliance option, 32 fatalities 
will be prevented and 797 injuries will be prevented or reduced in 
severity per year due to reductions in crashes involving blowouts and 
flat tires.
4. Unquantified Benefits
    The agency cannot quantify the benefits from a reduction in crashes 
associated with hydroplaning and overloading vehicles. The primary 
reason that the agency has been unable to quantify these benefits is 
the lack of crash data indicating tire pressure and how often these 
conditions are the cause or contributing factors in a crash. The agency 
does not collect tire pressure in its crash investigations. NHTSA also 
has not been able to quantify the benefits associated with reductions 
in property damage and travel delays that will result from fewer 
crashes or reductions in the severity of crashes.

B. Non-Tire Safety Benefits

    In its return letter, OMB stated that issuing a final rule that 
allowed current indirect TPMSs to comply would encourage vehicle 
manufacturers to install ABS on additional vehicles. OMB recommended 
that NHTSA consider the potential safety benefits of additional 
vehicles being equipped with ABS.
    However, as noted above in section VI., ``Response to Issues Raised 
in OMB Return Letter About Preliminary Determination,'' there is no 
reliable basis for concluding that permitting current indirect TPMSs to 
comply would lead to a significant increase in installation of ABS in 
light vehicles. Moreover, there is no statistically reliable basis for 
concluding that ABS reduces fatalities in light vehicles. Thus, the 
agency does not believe that, even if vehicle manufacturers install ABS 
on

[[Page 38740]]

additional vehicles, additional safety benefits would be experienced.

C. Total Quantified Safety Benefits

    The agency estimates that the total quantified safety benefits from 
reductions in crashes due to skidding/loss of control, stopping 
distance, and flat tires and blowouts, therefore, will be 124 
fatalities prevented and 8,722 injuries prevented or reduced in 
severity each year, if all light vehicles meet the four-tire, 25 
percent compliance option; and 79 fatalities prevented and 5,176 
injuries prevented or reduced in severity each year, if all light 
vehicles meet the one-tire, 30 percent compliance option.

D. Economic Benefits

1. Fuel Economy
    Correct tire pressure improves a vehicle's fuel economy. Recent 
data provided by Goodyear indicate that a vehicle's fuel efficiency is 
reduced by one percent for every 2.96 psi that its tires are below the 
placard pressure. The agency estimates that if all light vehicles meet 
the four-tire, 25 percent compliance option, vehicles' higher fuel 
economy will translate into an average discounted value of $16.43 per 
vehicle over the lifetime of the vehicle. If all light vehicles meet 
the one-tire, 30 percent compliance option, vehicles' higher fuel 
economy will translate into an average discounted value of $2.06 per 
vehicle over the lifetime of the vehicle.
2. Tread Life
    Correct tire pressure also increases a tire's tread life. Data from 
Goodyear indicate that for every 1 psi drop in tire pressure, tread 
life decreases by 1.78 percent. NHTSA estimates that if all light 
vehicles meet the four-tire, 25 percent compliance option, average 
tread life will increase by 1,143 miles. If all light vehicles meet the 
one-tire, 30 percent compliance option, average tread life will 
increase by 15 miles. This will delay new tire purchases. The agency 
estimates that the average discounted value of these delays in tire 
purchases will be $5.09, if all light vehicles meet the four-tire, 25 
percent compliance option; and $0.65 if all light vehicles meet the 
one-tire, 30 percent compliance option.

IX. Costs

A. Indirect TPMSs

    NHTSA estimates that the cost of an indirect TPMS that will meet 
the one-tire, 30 percent compliance option will be $13.29 per vehicle, 
if the vehicle already has a four-wheel, four-channel (four wheel-speed 
sensors) ABS. In the 2000 model year, about 67 percent of all new light 
vehicles were equipped with a four-wheel ABS. However, about 31 percent 
of these vehicles only had a three-channel system. A three-channel 
system has one wheel speed sensor for each front wheel and one for the 
rear axle. Thus, in order to meet the requirement that the TPMS be able 
to detect when any tire is significantly under-inflated, a vehicle with 
a three-channel ABS must be redesigned from having one wheel speed 
sensor for the rear axle to a wheel speed sensor for each rear wheel. 
The agency estimates that this will cost $25 per vehicle. Accordingly, 
the agency estimates that the average cost of providing an indirect 
TPMS to a vehicle already equipped with ABS will be $21.13 ($13.29 + 
$25 * .3135) per vehicle.
    For vehicles not currently equipped with ABS, manufacturers would 
have to install either four wheel speed sensors at a cost of $130 per 
vehicle, or ABS at a cost of $240 per vehicle, in addition to an 
indirect TPMS. Thus, the average cost of providing an indirect TPMS to 
a vehicle not already equipped with ABS will be $143.29 ($130 + $13.29) 
if the manufacturer installs four-wheel speed sensors, or $253.29 ($240 
+ $13.29) per vehicle if the manufacturer installs ABS.

B. Direct TPMSs

    NHTSA estimates that the cost of a direct TPMS that will meet the 
four-tire, 25 percent compliance option will be $70.35 per vehicle, if 
the manufacturer chooses to install an individual tire pressure 
display. This includes $7.50 for each tire pressure sensor ($30 per 
vehicle), $19 for the control module, $3.85 for an individual tire 
pressure display, $6 for four valves, and $11.50 for the combination of 
an instrument panel telltale, assembly, and miscellaneous wiring. The 
agency assumes that about one percent of vehicles currently comply. 
Thus, the agency estimates that the incremental cost will be $69.65 per 
vehicle ($70.35 * 99 percent) if manufacturers install an individual 
tire pressure display.\78\ If manufacturers install only a warning 
telltale, the agency estimates that the incremental cost will be $65.84 
($70.35 - $3.85 (the cost of a individual tire pressure display) * 99 
percent).
---------------------------------------------------------------------------

    \78\ The agency estimates that one percent of vehicles are 
currently equipped with a TPMS that complies with the requirements 
of the standard.
---------------------------------------------------------------------------

C. Hybrid TPMSs

    A hybrid TPMS consists of an indirect TPMS for vehicles equipped 
with an ABS and two direct pressure sensors and a radio frequency 
receiver. As noted above, insofar as NHTSA is aware, no manufacturer is 
currently planning to produce a hybrid TPMS. If a manufacturer were to 
produce a hybrid TPMS, the agency believes that such a system would be 
able to detect when one to four tires are 25 percent or more below 
placard. TRW estimated that the cost of such a system would be about 60 
percent of the cost of a direct TPMS. Since the hybrid TPMS would not 
be able to tell drivers the inflation pressure in all four tires, the 
agency assumes that this type of TPMS would not be accompanied by a 
display system that would allow the driver to see the pressure for each 
tire.
    Consequently, the agency estimates that the cost of a hybrid TPMS 
that would meet the four-tire, 25 percent compliance option would be 
$39.90 ($70.35 - $3.85 (the cost of an individual tire pressure 
display) * .60).

D. Vehicle Cost

    If all light vehicles meet the four-tire, 25 percent compliance 
option, the agency assumes that manufacturers will install hybrid TPMSs 
on the 67 percent of vehicles that are currently equipped with an ABS 
and direct TPMSs on the 33 percent of vehicles that are not so 
equipped. Thus, the agency estimates that the average incremental cost 
if all vehicles meet the four-tire, 25 percent compliance option will 
be $48.19 per vehicle [$39.90 x .67 + $66.50 x .33] x .99 (to account 
for one percent current compliance)). Since approximately 16 million 
vehicles are produced for sale in the U.S. each year, the total annual 
vehicle cost will be about $771 million per year.
    If all light vehicles meet the one-tire, 30 percent compliance 
option, the agency assumes that manufacturers will install an indirect 
TPMS on vehicles currently equipped with ABS (about 67 percent of new 
light vehicles), and a direct TPMS on vehicles not equipped with ABS 
(about 33 percent of new light vehicles). The agency also assumes that 
about five percent of vehicles currently meet the one-tire, 30 percent 
compliance option. Thus, the average incremental cost if all vehicles 
meet the one-tire, 30 percent compliance option will be $33.34 [($21.13 
* .67) + ($66.50 \79\* .33) * .95]. Since approximately 16 million 
vehicles are produced for sale in the U.S. each year, the total annual 
vehicle cost will be about $533 million per year.
---------------------------------------------------------------------------

    \79\ $66.50 is the cost of a direct TPMS with only a warning 
telltale.

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

[[Page 38741]]

E. Maintenance Costs

    Each pressure sensor in direct TPMSs needs a battery. Currently, 
these batteries last five to ten years. Thus, they will have to be 
replaced to keep the system functioning over the full life of a 
vehicle. At this time, all tire pressure sensors are enclosed packages 
that do not open so that the battery can be replaced. Thus, when the 
battery is depleted, the entire sensor must be replaced.
    To estimate the present discounted value of this cost, the agency 
is making the following assumptions. First, the agency assumes that the 
pressure sensors will be replaced the second time the vehicle's tires 
are changed, in the 90,000 to 100,000 mile range. The agency multiplied 
the cost of the sensor ($7.50 each, or $30 for the vehicle) by three to 
account for typical aftermarket markups. After applying discount 
factors, the agency estimates that the maintenance costs for direct 
TPMSs will be $40.91 per vehicle. For hybrid TPMSs, with direct 
pressure sensors in two wheels, the agency estimates the average 
maintenance costs will be half the maintenance costs of direct TPMSs, 
or $20.45.
    Thus, the agency estimates that if all light vehicles meet the 
four-tire, 25 percent compliance option, the present discounted value 
of the maintenance costs will be $27.20 ($20.45  x  .67 + $40.91  x  
.33) per vehicle. Since approximately 16 million vehicles are produced 
for sale in the Unites States each year, the total annual maintenance 
costs will be about $435 million.
    NHTSA notes that the maintenance costs associated with direct and 
hybrid TPMSs may decrease significantly in the future if manufacturers 
are able to mass produce a pressure sensor that does not require a 
battery. One TPMS manufacturer, IQ-mobil Electronics of Germany, 
commented that it has developed a ``batteryless transponder chip'' that 
``costs half as much as the battery transmitter it replaces.''
    Indirect TPMSs do not need a battery, and are assumed to have no 
maintenance costs for purposes of this analysis. If all light vehicles 
meet the one-tire, 30 percent compliance option, the agency assumes 
that manufacturers will install an indirect TPMS on vehicles currently 
equipped with ABS (about 67 percent of new light vehicles), and a 
direct TPMS on vehicles not equipped with ABS (about 33 percent of new 
light vehicles). Thus, the agency estimates that if all light vehicles 
meet the one-tire, 30 percent compliance option, the present discounted 
value of the maintenance costs will be $13.50 ($40.91  x  .33) per 
vehicle.

F. Testing Costs

    The agency estimates that the man-hours required to complete the 
necessary compliance testing will be 6 hours for a manager, 30 hours 
for a test engineer, and 30 hours for a technician/driver. The agency 
estimates that the labor costs will be $75 per hour for a manager, $53 
per hour for a test engineer, and $31 per hour for a technician/driver. 
Thus, the agency estimates that the total costs will be $2,970 per 
vehicle model under both compliance options.

G. Unquantified Costs

    The agency anticipates that there may be other maintenance costs 
for both direct and indirect TPMS. For example, with indirect TPMSs, 
there may be problems with wheel speed sensors and component failures. 
With direct TPMSs, the pressure sensors may be broken off when tires 
are changed. The agency requested comments on this issue in the NPRM, 
but received none. Without estimates of these maintenance problems and 
costs, the agency is unable to quantify their impact.
    The agency also notes that in order to benefit from the TPMS, 
drivers must respond to a warning by re-inflating their tires. To 
accomplish this, most drivers will either make a separate trip to a 
service station or take additional time to inflate their tires when 
they are at a service station for fuel. The process of checking and re-
inflating tires is relatively simple, and probably would take from 
three to five minutes. The time it would take to make a separate trip 
to a service station would vary depending on the driver's proximity to 
a station at the time he or she was notified.
    It is likely that drivers who take the time to re-inflate their 
tires would consider this extra time to be fairly trivial. Since the 
action is voluntary, by definition, they would consider it to be worth 
the potential benefits they will derive from properly inflated tires. 
However, when tallied across the entire driving population, the total 
effort involved in terms of man-hours may be significant. NHTSA has no 
data to indicate what portion of drivers would make a separate trip or 
wait to re-inflate their tires when they next visited a service 
station. Thus, the agency has not been able to quantify this cost.

H. ABS Costs

    As noted above, the agency estimates that the average cost of 
equipping a vehicle with ABS is $240.

I. Net Costs and Costs per Equivalent Life Saved

    The agency estimates that if all light vehicles meet the four-tire, 
25 percent compliance option, the net cost [vehicle cost + maintenance 
costs - (fuel savings + tread life savings)] will be $53.87 [$48.19 + 
$27.20 - ($16.43 + $5.09)]. As noted above, the agency estimates the 
total annual cost will be about $771 million. The agency estimates the 
total annual net cost will be about $862 million [$771 million + $435 
million - ($263 million + $81 million)]. NHTSA estimates that the net 
cost per equivalent life saved will be about $4.3 million.
    The agency estimates that if all light vehicles meet the one-tire, 
30 percent compliance option, the net cost will be $44.13 [$33.34 + 
$13.50 - ($2.06 + $0.65)]. The agency estimates that the total annual 
cost will be about $533 million per year, and the total annual net cost 
will be about $706 million [$533 million + $216 million - ($33 million 
+ $10 million)]. NHTSA estimates that the net cost per equivalent life 
saved will be about $5.8 million.

X. Rulemaking Analyses and Notices

A. 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:
    (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.
    This final rule is economically significant. Accordingly, it was 
reviewed under Executive Order 12866. The rule is also significant 
within the meaning of the Department of

[[Page 38742]]

Transportation's Regulatory Policies and Procedures. The agency has 
estimated that, under the first compliance option, compliance with this 
rule will cost $771 million per year, and under the second compliance 
option, compliance with this rule will cost $533 million, since 
approximately 16 million vehicles are produced for the United States 
market each year. Thus, this rule will have greater than a $100 million 
effect.
    Because this rule is significant, the agency has prepared a Final 
Economic Assessment (FEA). The Assessment is summarized above in 
section VIII., ``Benefits,'' and section IX., ``Costs.'' The FEA is 
available in the docket and has been placed on the agency's website 
along with the final rule itself.

B. Regulatory Flexibility Act

    Pursuant to the Regulatory Flexibility Act (5 U.S.C. 601 et seq., 
as amended by the Small Business Regulatory Enforcement Fairness Act 
(SBREFA) of 1996), whenever an agency is required to publish a notice 
of rulemaking for any proposed or final rule, it must prepare and make 
available for public comment a regulatory flexibility analysis that 
describes the effect of the rule on small entities (i.e., small 
businesses, small organizations, and small governmental jurisdictions). 
The Small Business Administration's regulations at 13 CFR part 121 
define a small business, in part, as a business entity ``which operates 
primarily within the United States.'' (13 CFR 121.105(a)). No 
regulatory flexibility analysis is required if the head of an agency 
certifies the rule will not have a significant economic impact on a 
substantial number of small entities. SBREFA amended the Regulatory 
Flexibility Act to require Federal agencies to provide a statement of 
the factual basis for certifying that a rule will not have a 
significant economic impact on a substantial number of small entities.
    NHTSA has considered the effects of this final rule under the 
Regulatory Flexibility Act. I certify that this final rule will not 
have a significant economic impact on a substantial number of small 
entities. The rationale for this certification is that currently there 
are only four small motor vehicle manufacturers (i.e., only four with 
fewer than 1,000 employees) in the United States that will have to 
comply with this final rule. These manufacturers will have to rely on 
suppliers to provide the TPMS hardware, and then they will have to 
integrate the TPMS into their vehicles.
    There are a few small manufacturers that manufacture recreational 
vehicles that will have to comply with this final rule. However, most 
of these manufacturers use van chassis supplied by the larger 
manufacturers, e.g., GM, Ford, or DaimlerChrysler, and could use the 
TPMSs supplied with the chassis. These manufacturers should not have to 
test the TPMS for compliance with this final rule since they should be 
able to rely upon the chassis manufacturer's incomplete vehicle 
documentation.
    The agency has eliminated the most significant potential impact on 
small businesses by deciding not to require TPMSs to function when the 
vehicle's original rims are replaced with aftermarket wheels and rims 
that are not identical to the original wheels and rims.

C. 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 rule will not have any significant impact on the 
quality of the human environment.

D. Executive Order 13132 (Federalism)

    Executive Order 13132 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'' is 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 
regulation. NHTSA also may not issue a regulation with Federalism 
implications and that preempts State law unless the agency consults 
with State and local officials early in the process of developing the 
regulation.
    The agency has analyzed this final rule in accordance with the 
principles and criteria set forth in Executive Order 13132 and has 
determined that it will not have sufficient federalism implications to 
warrant consultation with State and local officials or the preparation 
of a federalism summary impact statement. The final rule will not have 
any substantial effects on the States, or on the current Federal-State 
relationship, or on the current distribution of power and 
responsibilities among the various local officials. While the agency is 
providing compliance options, it is not seeking to give each of those 
options pre-emptive effect.

E. Civil Justice Reform

    This final rule will 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 suit in court.

F. 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. The 
Department of Transportation is submitting the following information 
collection request to OMB for review and clearance under the PRA.
    Agency: National Highway Traffic Safety Administration (NHTSA).
    Title: Phase-In Production Reporting Requirements for Tire Pressure 
Monitoring Systems.
    Type of Request: Routine.
    OMB Clearance Number: 2127-New.
    Form Number: This collection of information will not use any 
standard forms.
    Affected Public: The respondents are manufacturers of passenger 
cars, multipurpose passenger vehicles, trucks, and buses having a gross 
vehicle weight rating of 10,000 pounds or less. The agency estimates 
that there are about 21 such manufacturers.
    Estimate of the Total Annual Reporting and Recordkeeping Burden 
Resulting from the Collection of Information: NHTSA estimates that the 
total annual hour burden is 42 hours.

[[Page 38743]]

    Estimated Costs: NHTSA estimates that the total annual cost burden, 
in U.S. dollars, will be $0. No additional resources will be expended 
by vehicle manufacturers to gather annual production information 
because they already compile this data for their own uses.
    Summary of Collection of Information: This collection will require 
manufacturers of passenger cars, multipurpose passenger vehicles, 
trucks, and buses with a gross vehicle weight rating of 10,000 pounds 
or less, except those vehicles with dual wheels on an axle, to provide 
motor vehicle production data for the following three years: November 
1, 2003 to October 31, 2004; November 1, 2004 to October 31, 2005; and 
November 1, 2005 to October 31, 2006.
    Description of the Need for the Information and the Proposed Use of 
the Information: The purpose of the reporting requirements will be to 
aid NHTSA in determining whether a manufacturer has complied with the 
requirements of Federal Motor Vehicle Safety Standard No. 138, Tire 
pressure monitoring systems, during the phase-in of those requirements. 
NHTSA requests comments on the agency's estimates of the total annual 
hour and cost burdens resulting from this collection of information. 
These comments must be received on or before August 5, 2002.

G. National Technology Transfer and Advancement Act

    Section 12(d) of the National Technology Transfer and Advancement 
Act of 1995 (NTTAA), Public Law 104-113, section 12(d) (15 U.S.C. 272) 
directs NHTSA to use voluntary consensus standards in its regulatory 
activities unless doing so would be inconsistent with applicable law or 
otherwise impractical. Voluntary consensus standards are technical 
standards (e.g., materials specifications, test methods, sampling 
procedures, and business practices) that are developed or adopted by 
voluntary consensus standards bodies, such as the Society of Automotive 
Engineers (SAE). The NTTAA directs NHTSA to provide Congress, through 
OMB, explanations when the agency decides not to use available and 
applicable voluntary consensus standards. The NTTAA does not apply to 
symbols.
    There are no voluntary consensus standards available at this time. 
However, NHTSA will consider any such standards when they become 
available.

H. 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 in any one year (adjusted for inflation with base 
year of 1995). Before promulgating a rule for which a written statement 
is needed, section 205 of the UMRA generally requires NHTSA 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 NHTSA 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 why that 
alternative was not adopted.
    This final rule will not result in the expenditure by State, local, 
or tribal governments, in the aggregate, of more than $100 million 
annually, but it will result in the expenditure of that magnitude by 
vehicle manufacturers and/or their suppliers. In the NPRM, the agency 
requested comments on two alternatives for achieving the purposes of 
the TREAD Act mandate. In the final rule, the agency has chosen two 
compliance options that will provide the manufacturers with broad 
flexibility to minimize their costs of compliance with the Standard 
during the phase-in period.

I. Regulation 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.

List of Subjects in 49 CFR Parts 571 and 590

    Imports, Motor vehicle safety, Reporting and recordkeeping 
requirements, Tires.
    In consideration of the foregoing, NHTSA is amending 49 CFR parts 
571 and 590 as follows:

PART 571--FEDERAL MOTOR VEHICLE SAFETY STANDARDS

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

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


    2. In Sec. 571.101, paragraph S5.2.3 and Table 2 are revised to 
read as follows:


Sec. 571.101  Standard No. 101; Controls and displays.

* * * * *
    S5.2.3 Except for the Low Tire Pressure Telltale (that does not 
identify which tire has low pressure), any display located within the 
passenger compartment and listed in column 1 of Table 2 that has a 
symbol designated in column 4 of that table shall be identified by 
either the symbol designated in column 4 (or symbol substantially 
similar in form to that shown in column 4) or the word or abbreviation 
shown in column 3. The Low Tire Pressure Telltale (that does not 
identify which tire has low tire pressure) shall be identified by 
either the symbol designated in column 4, or the symbol and the words 
designated in column 4 and column 3, respectively. Additional words or 
symbols may be used at the manufacturer's discretion for the purpose of 
clarity. Any telltales used in conjunction with a gauge need not be 
identified. The identification required or permitted by this section 
shall be placed on or adjacent to the display that it identifies. The 
identification of any display shall, under the conditions of S6, be 
visible to the driver and appear to the driver perceptually upright.
* * * * *
BILLING CODE 4910-59-P

[[Page 38744]]

[GRAPHIC] [TIFF OMITTED] TR05JN02.001


[[Page 38745]]


[GRAPHIC] [TIFF OMITTED] TR05JN02.002

BILLING CODE 4910-59-C

[[Page 38746]]


    3. Section 571.138 is added to read as follows:


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

    S1.  Purpose and scope. This standard specifies performance 
requirements for tire pressure monitoring systems to prevent 
significant under-inflation of tires and the resulting safety problems.
    S2.  Application. This standard applies to passenger cars, 
multipurpose passenger vehicles, trucks, and buses that have a gross 
vehicle weight rating of 4,536 kilograms (10,000 pounds) or less, 
except those vehicles with dual wheels on an axle, according to the 
phase-in schedule specified in S7 of this standard.
    S3.  Definitions. The following definitions apply to this standard:
    Lightly loaded vehicle weight means unloaded vehicle weight plus 
the weight of a mass of 180 kg (396 pounds), including test driver and 
instrumentation.
    Tire pressure monitoring system means a system that detects when 
one or more of a vehicle's tires are under-inflated and illuminates a 
low tire pressure warning telltale.
    S4.  Requirements.
    S4.1  General. To the extent provided in S7.1 through S7.3, each 
vehicle must be equipped with a tire pressure monitoring system that 
meets the requirements specified in S4 under the test procedures 
specified in S6 of this standard. Prior to November 1, 2006, each tire 
pressure monitoring system must conform, at the manufacturer's option, 
to either S4.2.1 or S4.2.2 of this standard. The manufacturer must 
select the option by the time it certifies the vehicle and may not 
thereafter select a different option for the vehicle.
    S4.2  Tire pressure monitoring systems: vehicles manufactured after 
October 31, 2003 and before November 1, 2006.
    S4.2.1  Option 1: Four tires; 25 percent under-inflation. The tire 
pressure monitoring system must:
    (a) Illuminate a low tire pressure warning telltale not more than 
10 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 this standard for the corresponding type of tire, whichever 
is higher; and
    (b) Continue to illuminate the low tire pressure warning telltale 
as long as the pressure in any of the vehicle's tires is equal to or 
less than the pressure specified in (a), and the key locking system is 
in the ``On'' (``Run'') position, whether or not the engine is running, 
or until manually reset in accordance with the vehicle manufacturer's 
instructions.
    S4.2.2  Option 2: One tire; 30 percent under-inflation. The tire 
pressure monitoring system must:
    (a) Illuminate a low tire pressure warning telltale not more than 
10 minutes after the inflation pressure in one of the vehicle's tires 
is equal to or less than either the pressure 30 percent below the 
vehicle manufacturer's recommended cold inflation pressure, or the 
pressure specified in the 3rd column of Table 1 of this standard for 
the corresponding type of tire, whichever is higher; and
    (b) Continue to illuminate the low tire pressure warning telltale 
as long as the pressure in that tire is equal to or less than the 
pressure specified in (a), and the key locking system is in the ``On'' 
(``Run'') position, whether or not the engine is running, or until 
manually reset in accordance with the vehicle manufacturer's 
instructions.
    S4.3  Low tire pressure warning telltale.
    S4.3.1  Each tire pressure monitoring system must include a low 
tire pressure warning telltale that:
    (a) Is mounted inside the occupant compartment in front of and in 
clear view of the driver;
    (b) Is identified by one of the symbols shown for the ``Low Tire 
Pressure Telltale'' in Table 2 of Standard No. 101 (Sec. 571.101); and
    (c) Is illuminated under the conditions specified in S4.2.1 or 
S4.2.2.
    S4.3.2  In the case of a telltale that identifies which tire(s) is 
(are) under-inflated, each tire in the symbol for that telltale must 
illuminate when the tire it represents is under-inflated to the extent 
specified in either S4.2.1 or S4.2.2.
    S4.3.3  (a) Except as provided in paragraph (b) of this section, 
each low tire pressure warning telltale must be activated as a check of 
lamp function either when the key locking system is turned to the 
``On'' (``Run'') position when the engine is not running, or when the 
key locking system is in a position between ``On'' (``Run'') and 
``Start'' that is designated by the manufacturer as a check position.
    (b) The low tire pressure warning telltale need not be activated 
when a starter interlock is in operation.
    S4.4  Replacement tires. Each tire pressure monitoring system must 
continue to meet the requirements of this standard when the vehicle's 
original tires are replaced with tires of any optional or replacement 
size(s) recommended for the vehicle by the vehicle manufacturer.
    S4.5  Written instructions.
    S4.5.1  Vehicles certified to Option 1: Four tires; 25 percent 
under-inflation. The owner's manual in each vehicle certified as 
complying with S4.2.1 must provide an image of the Low Tire Pressure 
Telltale symbol with the following statement, in English: ``When the 
tire pressure monitoring system warning light is lit, one or more of 
your tires is significantly under-inflated. You should stop and check 
your tires as soon as possible, and inflate them to the proper pressure 
as indicated on the vehicle's tire information placard. 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. Each tire, including the spare, should be checked monthly when 
cold and set to the recommended inflation pressure as specified in the 
vehicle placard and owner's manual.'' Each vehicle manufacturer may, at 
its discretion, provide additional information about the significance 
of the low tire pressure warning telltale illuminating, description of 
corrective action to be undertaken, whether the tire pressure 
monitoring system functions with the vehicle's spare tire, and how to 
use the reset button, if one is provided.
    S4.5.2  Vehicles manufactured after October 31, 2003 and before 
November 1, 2006, and certified to Option 2: One tire; 30 percent 
under-inflation. The owner's manual in each vehicle certified as 
complying with S4.2.2 must comply with S4.5.1 and provide the following 
statement, in English:

    ``Note:
    The tire pressure monitoring system on your vehicle will warn 
you when one of your tires is significantly under-inflated and when 
some combinations of your tires are significantly under-inflated. 
However, there are other combinations of significantly under-
inflated tires for which your tire pressure monitoring system may 
not warn you. These other combinations are relatively common, 
accounting for approximately half the instances in which vehicles 
have significantly under-inflated tires. For example, your system 
may not warn you when both tires on the same side or on the same 
axle of your vehicle are significantly under-inflated. It is 
particularly important, therefore, for you to check the tire 
pressure in all of your tires regularly and maintain proper 
pressure.''

    S5.  Test conditions.
    S5.1  Ambient temperature. The ambient temperature is between 
0 deg.C (32 deg.F) and 40 deg.C (104 deg.F).
    S5.2  Road test surface. Road tests are conducted on a dry, smooth 
roadway.

[[Page 38747]]

    S5.3  Vehicle conditions.
    S5.3.1  Test weight. The vehicle is tested at its lightly loaded 
vehicle weight and at its gross vehicle weight rating without exceeding 
any of its gross axle weight ratings.
    S5.3.2  Vehicle speed. The vehicle is tested at a speed between 50 
km/h (31.1 mph) and 100 km/h (62.2 mph).
    S6.  Test procedures.
    (a) Inflate the vehicle's tires to the vehicle manufacturer's 
recommended cold inflation pressure for the applicable vehicle load 
conditions specified in paragraph S5.3.1 of this standard. If the 
vehicle manufacturer has not recommended an inflation pressure for the 
lightly loaded condition, the inflation pressure specified by the 
vehicle manufacturer for the gross vehicle weight rating is used.
    (b) With the vehicle stationary and the key locking system in the 
``Lock'' or ``Off'' position, turn the key locking system to the ``On'' 
or ``Run'' position. The tire pressure monitoring system must perform a 
check of telltale lamp function as specified in paragraph S4.3.3 of 
this standard.
    (c) If applicable, reset the tire pressure monitoring system in 
accordance with the instructions specified in the vehicle owner's 
manual.
    (d) Drive the vehicle at any speed specified in paragraph S5.3.2 of 
this standard for 20 minutes.
    (e)(1) For vehicles complying with S4.2.1, 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 low 
tire pressure monitoring system is required to activate the low tire 
pressure warning telltale for that vehicle.
    (2) For vehicles complying with S4.2.2, stop the vehicle and 
deflate any one tire until the deflated tire is at 7 kPa (1 psi) below 
the inflation pressure at which the low tire pressure monitoring system 
is required to activate the low tire pressure warning telltale for that 
vehicle.
    (f) Drive the vehicle at any speed specified in paragraph S5.3.2 of 
this standard. Record the time from when the vehicle speed reaches 50 
km/h until the time the low tire pressure warning telltale illuminates. 
The telltale must illuminate within 10 minutes as required in paragraph 
S4.2.1(a) or S4.2.2(a) of this standard.
    (g) Stop the vehicle and turn the key locking system to the ``Off'' 
or ``Lock'' position. After a 5 minute period, turn the vehicle's key 
locking system to the ``On'' or ``Run'' position. The telltale must 
remain illuminated.
    (h) Keep the vehicle stationary for a period of one hour.
    (i) Inflate all of the vehicle's tires to the vehicle 
manufacturer's recommended cold inflation pressure. If the vehicle's 
tire pressure monitoring system has a manual reset feature, reset the 
system in accordance with the instructions specified in the vehicle 
owner's manual.
    (j) Drive the vehicle at any speed specified in paragraph S5.3.2 of 
this standard. The telltale must extinguish as specified in paragraph 
S4.2.1(b) or S4.2.2(b).
    (k)(1) For vehicles complying with S4.2.1, if additional 
combinations of tires are tested, repeat the test procedures in 
paragraphs S6(a) through (j).
    (2) For vehicles complying with S4.2.2, if the other individual 
tires are tested, repeat the test procedures in paragraphs S6(a) 
through (j).
    (l) Utilizing the existing vehicle rims, repeat the test procedures 
in paragraphs S6(a) through (k) for each tire size recommended for the 
vehicle by the vehicle manufacturer. Note: If a different rim size is 
required, OEM rim and tire assemblies appropriate for the tire pressure 
monitoring system are used for testing.
    S7.  Phase-In Schedule.
    S7.1  Vehicles manufactured on or after November 1, 2003, and 
before November 1, 2004. For vehicles manufactured on or after November 
1, 2003, and before November 1, 2004, the number of vehicles complying 
with this standard must not be less than 10 percent of:
    (a) The manufacturer's average annual production of vehicles 
manufactured on or after November 1, 2000, and before November 1, 2003; 
or
    (b) The manufacturer's production on or after November 1, 2003, and 
before November 1, 2004.
    S7.2  Vehicles manufactured on or after November 1, 2004, and 
before November 1, 2005. For vehicles manufactured on or after November 
1, 2004, and before November 1, 2005, the number of vehicles complying 
with this standard must not be less than 35 percent of:
    (a) The manufacturer's average annual production of vehicles 
manufactured on or after November 1, 2001, and before November 1, 2004; 
or
    (b) The manufacturer's production on or after November 1, 2004, and 
before November 1, 2005.
    S7.3  Vehicles manufactured on or after November 1, 2005, and 
before November 1, 2006. For vehicles manufactured on or after November 
1, 2005, and before November 1, 2006, the number of vehicles complying 
with this standard must not be less than 65 percent of:
    (a) The manufacturer's average annual production of vehicles 
manufactured on or after November 1, 2002, and before November 1, 2005; 
or
    (b) The manufacturer's production on or after November 1, 2005, and 
before November 1, 2006.
    S7.4  Calculation of complying vehicles.
    (a) For purposes of complying with S7.1, a manufacturer may count a 
vehicle if it:
    (1) Is manufactured on or after November 1, 2003, but before 
November 1, 2004; or
    (2) Complies with S4.2.1 or S4.2.2 of this standard.
    (b) For purposes of complying with S7.2, a manufacturer may count a 
vehicle if it:
    (1)
    (i) Is manufactured on or after November 1, 2003, but before 
November 1, 2005;
    (ii) Is not counted toward compliance with S7.1; and
    (iii) Complies with S4.2.1 of this standard, or
    (2)
    (i) Is manufactured on or after November 1, 2004, but before 
November 1, 2005; and
    (ii) Complies with S4.2.2 of this standard.
    (c) For purposes of complying with S7.3, a manufacturer may count a 
vehicle if it:
    (i) Is manufactured on or after November 1, 2003, but before 
November 1, 2006;
    (ii) Is not counted toward compliance with S7.1 or S7.2; and
    (iii) Complies with S4.2.1 of this standard, or
    (2)
    (i) Is manufactured on or after November 1, 2005, but before 
November 1, 2006; and
    (ii) Complies with S4.2.2 of this standard.
    S7.5  Vehicles produced by more than one manufacturer.
    S7.5.1  For the purpose of calculating average annual production of 
vehicles for each manufacturer and the number of vehicles manufactured 
by each manufacturer under S7.1 through S7.3, a vehicle produced by 
more than one manufacturer must be attributed to a single manufacturer 
as follows, subject to 7.5.2:
    (a) A vehicle that is imported must be attributed to the importer.
    (b) A vehicle manufactured in the United States by more than one 
manufacturer, one of which also

[[Page 38748]]

markets the vehicle, must be attributed to the manufacturer that 
markets the vehicle.
    S7.5.2  A vehicle produced by more than one manufacturer must be 
attributed to any one of the vehicle's manufacturers specified by an 
express written contract, reported to the National Highway Traffic 
Safety Administration under 49 CFR Part 590, between the manufacturer 
so specified and the manufacturer to which the vehicle would otherwise 
be attributed under S7.5.1.
    S7.6  Small volume manufacturers. Vehicles manufactured during any 
of the three years of the November 1, 2003 to October 31, 2006 phase-in 
by a manufacturer that produces fewer than 5,000 vehicles worldwide 
during that year are not required to comply with the standard.
    Tables to Sec. 571.138

                    Table 1.--Low Tire Pressure Warning Telltale--Minimum Activation Pressure
----------------------------------------------------------------------------------------------------------------
                                             Maximum or rated inflation pressure           Minimum activation
                                     --------------------------------------------------         pressure
              Tire type                                                                -------------------------
                                               (kPa)                    (psi)              (kPa)        (psi)
----------------------------------------------------------------------------------------------------------------
P-metric--Standard Load.............  240, 300, or 350.......  35, 44, or 51..........          140           20
P-metric--Extra Load................  280 or 340.............  41 or 49...............          160           23
Load Range C........................  350....................  51.....................          200           29
Load Range D........................  450....................  65.....................          260           38
Load Range E........................  550....................  80.....................          320           46
----------------------------------------------------------------------------------------------------------------


    4. Part 590 is revised to read as follows:

PART 590--TIRE PRESSURE MONITORING SYSTEM PHASE-IN REPORTING 
REQUIREMENTS

Sec.
590.1   Scope.
590.2   Purpose.
590.3   Applicability.
590.4   Definitions.
590.5   Response to inquiries.
590.6   Reporting requirements.
590.7   Records.
590.8   Petition to extend period to file report.

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


Sec. 590.1  Scope.

    This part establishes requirements for manufacturers 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, to submit a report, 
and maintain records related to the report, concerning the number of 
such vehicles that meet the requirements of Standard No. 138, Tire 
pressure monitoring systems (49 CFR 571.138).


Sec. 590.2  Purpose.

    The purpose of these reporting requirements is to assist the 
National Highway Traffic Safety Administration in determining whether a 
manufacturer has complied with Standard No. 138 (49 CFR 571.138).


Sec. 590.3  Applicability.

    This part applies to manufacturers 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.


Sec. 590.4  Definitions.

    (a) All terms defined in 49 U.S.C. 30102 are used in their 
statutory meaning.
    (b) Bus, gross vehicle weight rating, multipurpose passenger 
vehicle, passenger car, and trucks are used as defined in 49 CFR 571.3.
    (c) Production year means the 12-month period between November 1 of 
one year and October 31 of the following year, inclusive.


Sec. 590.5  Response to inquiries.

    At any time during the production years ending October 31, 2004, 
October 31, 2005, and October 31, 2006, each manufacturer must, upon 
request from the Office of Vehicle Safety Compliance, provide 
information identifying the vehicles (by make, model, and vehicle 
identification number) that have been certified as complying with 
Standard No. 138. The manufacturer's designation of a vehicle as a 
certified vehicle is irrevocable.


Sec. 590.6  Reporting requirements.

    (a) General reporting requirements. Within 60 days after the end of 
the production years ending October 31, 2004, October 31, 2005, and 
October 31, 2006, each manufacturer must submit a report to the 
National Highway Traffic Safety Administration concerning its 
compliance with Standard No. 138 (49 CFR 571.138) for its passenger 
cars, multipurpose passenger vehicles, trucks, and buses with a gross 
vehicle weight rating of less than 4,536 kilograms (10,000 pounds) 
produced in that year. Each report must--
    (1) Identify the manufacturer;
    (2) State the full name, title, and address of the official 
responsible for preparing the report;
    (3) Identify the production year being reported on;
    (4) Contain a statement regarding whether or not the manufacturer 
complied with the requirements of Standard No. 138 (49 CFR 571.138) for 
the period covered by the report and the basis for that statement;
    (5) Provide the information specified in paragraph (b) of this 
section;
    (6) Be written in the English language; and
    (7) Be submitted to: Administrator, National Highway Traffic Safety 
Administration, 400 Seventh Street, SW., Washington, DC 20590.
    (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 of the three 
previous production years, or, at the manufacturer's option, for the 
current production year. 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 current production 
year.
    (2) Production. Each manufacturer must report for the production 
year for which the report is filed: 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 that meet 
Standard No. 138 (49 CFR 571.138).

[[Page 38749]]

    (3) Vehicles produced by more than one manufacturer. Each 
manufacturer whose reporting of information is affected by one or more 
of the express written contracts permitted by S7.5(c)(3) of Standard 
No. 138 (49 CFR 571.138) must:
    (i) Report the existence of each contract, including the names of 
all parties to the contract, and explain how the contract affects the 
report being submitted.
    (ii) Report the actual number of vehicles covered by each contract.


Sec. 590.7  Records.

    Each manufacturer must maintain records of the Vehicle 
Identification Number for each vehicle for which information is 
reported under Sec. 590.6(b)(2) until December 31, 2008.


Sec. 590.8  Petition to extend period to file report.

    A manufacturer may petition for extension of time to submit a 
report under this Part. A petition will be granted only if the 
petitioner shows good cause for the extension and if the extension is 
consistent with the public interest. The petition must be received not 
later than 15 days before expiration of the time stated in 
Sec. 590.6(a). The filing of a petition does not automatically extend 
the time for filing a report. The petition must be submitted to: 
Administrator, National Highway Traffic Safety Administration, 400 
Seventh Street, SW., Washington, DC 20590.

    Issued: May 30, 2002.
Jeffrey W. Runge,
Administrator.
[FR Doc. 02-13915 Filed 5-30-02; 2:30 pm]
BILLING CODE 4910-59-P