Federal Register, Volume 71 Issue 180 (Monday, September 18, 2006)

[Federal Register Volume 71, Number 180 (Monday, September 18, 2006)]
[Proposed Rules]
[Pages 54712-54753]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 06-7598]

[[Page 54711]]

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Part II

Department of Transportation

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National Highway Traffic Safety Administration

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49 CFR Parts 571 and 585

Federal Motor Vehicle Safety Standards; Electronic Stability Control
Systems; Proposed Rule

Federal Register / Vol. 71, No. 180 / Monday, September 18, 2006 /
Proposed Rules

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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Parts 571 and 585

[Docket No. NHTSA-2006-25801]
RIN 2127-AJ77

Federal Motor Vehicle Safety Standards; Electronic Stability
Control Systems

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

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: As part of a comprehensive plan for reducing the serious risk
of rollover crashes and the risk of death and serious injury in those
crashes, this document proposes to establish a new Federal motor
vehicle safety standard (FMVSS) No. 126 to require electronic stability
control (ESC) systems on passenger cars, multipurpose vehicles, trucks
and buses with a gross vehicle weight rating of 4,536 Kg (10,000
pounds) or less. ESC systems use automatic computer-controlled braking
of individual wheels to assist the driver in maintaining control in
critical driving situations in which the vehicle is beginning to lose
directional stability at the rear wheels (spin out) or directional
control at the front wheels (plow out).
Based on our own crash data studies, NHTSA estimates that the
installation of ESC will reduce single-vehicle crashes of passenger
cars by 34 percent and single vehicle crashes of sport utility vehicles
(SUVs) by 59 percent, with a much greater reduction of rollover
crashes.
Preventing single-vehicle loss-of-control crashes is the most
effective way to reduce deaths resulting from rollover crashes. This is
because most loss of control crashes culminate in the vehicle leaving
the roadway, which dramatically increases the probability of a
rollover. NHTSA estimates that ESC has the potential to prevent 71
percent of passenger car rollovers and 84 percent of SUV rollovers in
single-vehicle crashes.
NHTSA estimates that ESC would save 5,300 to 10,300 lives and
prevent 168,000 to 252,000 injuries in all types of crashes annually if
all light vehicles on the road were equipped with ESC systems. ESC
systems would substantially reduce (by 4,200 to 5,400) of the more than
10,000 deaths each year on American roads resulting from rollover
crashes.
About 29 percent of model year (MY) 2006 light vehicles sold in the
U.S. were equipped with ESC, and manufacturers intend to increase the
number of ESC installations in light vehicles to 71 percent by MY 2011.
This rule would require a 100 percent installation rate for ESC by MY
2012 (with exceptions for some vehicles manufactured in stages or by
small volume manufacturers). Of the overall projected annual 5,300 to
10,300 highway deaths and 168,000 to 252,000 injuries prevented, we
would attribute 1,536 to 2,211 prevented fatalities (including 1,161 to
1,445 involving rollover) to this proposed rulemaking, in addition to
the prevention of 50,594 to 69,630 injuries.

DATES: You should submit your comments early enough to ensure that
Docket Management receives them not later than November 17, 2006.

ADDRESSES: You may submit comments identified by DOT DMS Docket Number
above by any of the following methods:
Web Site: http://dms.dot.gov. Follow the instructions for
submitting comments on the DOT electronic docket site.
Fax: 1-202-493-2251.
Mail: Docket Management Facility; U.S. Department of
Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401,
Washington, DC 20590
Hand Delivery: Room PL-401 on the plaza level of the
Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9
a.m. and 5 p.m., Monday through Friday, except Federal Holidays.
Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the online instructions for submitting
comments.
Instructions: All submissions must include the agency name and
docket number or Regulatory Identification Number (RIN) for this
rulemaking. For detailed instructions on submitting comments and
additional information on the rulemaking process, see the Public
Participation heading of the Supplementary Information section of this
document. Note that all comments received will be posted without change
to http://dms.dot.gov, including any personal information provided.
Please see the Privacy Act heading under Regulatory Notices.
Docket: For access to the docket to read background documents or
comments received, go to http://dms.dot.gov at any time or to Room PL-
401 on the plaza level of the Nassif Building, 400 Seventh Street, SW.,
Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday,
except Federal Holidays.

FOR FURTHER INFORMATION CONTACT: For non-legal issues, you may call Mr.
Patrick Boyd, Office of Crash Avoidance Standards at (202) 366-2272.
His FAX number is (202) 366-7002.
For legal issues, you may call Mr. Eric Stas, Office of the Chief
Counsel at (202) 366-2992. His FAX number is (202) 366-3820.
You may send mail to both of these officials at National Highway
Traffic Safety Administration, 400 Seventh Street, SW., Washington, DC
20590.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Executive Summary
II. Safety Problems Addressed by the Proposed Standard
A. Single-Vehicle Crash and Rollover Statistics
B. The Agency's Comprehensive Response to Rollover
III. Electronic Stability Control Systems
A. How ESC Prevents Loss of Vehicle Control
B. Additional Features of Some ESC Systems
IV. Effectiveness of ESC
A. Human Factors Study on the Effectiveness of ESC
B. Crash Data Studies of ESC Effectiveness
V. Agency Proposal
A. Definition of ESC
B. Performance Test of ESC Oversteer Intervention and Stability
Criteria
C. Responsiveness Criteria
D. Other Issues
1. ESC Off Switches
2. ESC Activation and Malfunction Symbols and Telltale
3. ESC Off Switch Symbol and Telltale
E. Alternatives to the Agency Proposal
VI. Leadtime
VII. Benefits and Costs
A. Summary
B. ESC Benefits
C. ESC Costs
VIII. Public Participation
IX. Regulatory Analyses and Notices

I. Executive Summary

As part of a comprehensive plan for reducing the serious risk of
rollover crashes and the risk of death and serious injury in those
crashes, this rule proposes to establish Federal Motor Vehicle Safety
Standard (FMVSS) No. 126, Electronic Stability Control Systems, which
would require passenger cars, multipurpose passenger vehicles (MPVs),
trucks, and buses that have a gross vehicle weight rating (GVWR) of
4,536 kg (10,000 pounds) or less to be equipped with an ESC system that
meets the requirements of the standard. ESC systems use automatic,
computer-controlled braking of individual wheels to assist the driver
in maintaining control (and the vehicle's intended heading) in
situations where the vehicle is beginning to lose directional stability
(e.g., where the driver misjudges the severity of a curve

[[Page 54713]]

or over-corrects in an emergency situation). In such situations (which
occur with considerable frequency), intervention by the ESC system can
assist the driver in preventing the vehicle from leaving the roadway,
thereby preventing fatalities and injuries associated with crashes
involving vehicle rollover or collision with various objects (e.g.,
trees, highway infrastructure, other vehicles).
Based upon current estimates regarding the effectiveness of ESC
systems, we believe that an ESC standard could save thousands of lives
each year, providing potentially the greatest safety benefits produced
by any safety device since the introduction of seat belts. The
following discussion highlights the research and regulatory efforts
that have culminated in the present proposal.
Since the early 1990's, NHTSA has been actively engaged in finding
ways to address the problem of vehicle rollover, because crashes
involving rollover are responsible for a disproportionate number of
fatalities and serious injuries (over 10,000 of the 33,000 fatalities
of vehicle occupants in 2004). Although various options were explored,
the agency ultimately chose to add a rollover resistance component to
its New Car Assessment Program (NCAP) consumer information program in
2001. In response to NCAP's market-based incentives, vehicle
manufacturers made modifications to their product lines to increase
their vehicles' geometric stability and rollover resistance by
utilizing wider track widths (typically associated with passenger cars)
on many of their newer sport utility vehicles (SUVs) and by making
other improvements to truck-based SUVs during major redesigns (e.g.,
introduction of roll stability control). This approach was successful
in terms of reducing the much higher rollover rate of SUVs and other
high-center-of-gravity vehicles, as compared to passenger cars.
However, manipulating vehicle configuration alone cannot entirely
resolve the rollover problem (particularly when consumers continue to
demand vehicles with greater carrying capacity and higher ground
clearance).
Accordingly, the agency began exploring technologies that could
confront the issue of vehicle rollover from a different perspective or
line of inquiry, which led to today's proposal. We believe that our
proposed ESC requirement offers a complementary approach that would
provide substantial benefits to drivers of both passenger cars and LTVs
(light trucks/vans). Undoubtedly, keeping vehicles from leaving the
roadway is the best way to prevent deaths and injuries associated with
rollover, as well as other types of crashes. Based on its crash data
studies, NHTSA estimates that the installation of ESC systems will
reduce single vehicle crashes of passenger cars by 34 percent and
single vehicle crashes of sport utility vehicles (SUVs) by 59 percent.
Its effectiveness is especially great for single-vehicle crashes
resulting in rollover, where ESC systems were estimated to prevent 71
percent of passenger car rollovers and 84 percent of SUV rollovers in
single vehicle crashes (see section VII).
In short, we believe that preventing single-vehicle loss-of-control
crashes is the most effective way to reduce rollover deaths, and we
believe that ESC offers considerable promise in terms of meeting this
important safety objective while maintaining a broad range of vehicle
choice for consumers. In fact, among the agency's ongoing and planned
rulemakings, it is the single most effective way of reducing the total
number of traffic deaths. It is also the most cost-effective of those
rulemakings.
We note that this proposal is consistent with recent congressional
legislation contained in section 10301 of the Safe, Accountable,
Flexible, Efficient Transportation Equity Act: A Legacy for Users of
2005 (SAFETEA-LU).\1\ That provision requires the Secretary of
Transportation to ``establish performance criteria to reduce the
occurrence of rollovers consistent with stability enhancing
technologies'' and to ``issue a proposed rule * * * by October 1, 2006,
and a final rule by April 1, 2009.''
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\1\ Pub. L. 109-59, 119 Stat. 1144 (2005).
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The balance of this notice explains in detail: (1) The size of the
safety problem (see section II); (2) how ESC systems would act to
mitigate that safety problem (see section II); (3) the basics of ESC
operation (see section III); (4) findings from ESC-related research
(see section IV);(5) the specifics of our regulatory proposal (see
section V); (6) lead time and phase-in requirements (see section VI),
and (7) costs and benefits associated with this proposal (see section
VII). The following section summarizes the key points of the proposal.

A. Proposed Requirements for ESC Systems

Consistent with the congressional mandate in section 10301 of
SAFETEA-LU, NHTSA is proposing to require all light vehicles to be
equipped with an ESC system with, at the minimum, the capabilities of
current production systems. We believe that a requirement for such ESC
systems would be practicable in terms of both ensuring technological
feasibility and providing the desired safety benefits in a cost-
effective manner. Although vehicle manufacturers have been increasing
the share of the light vehicle fleet equipped with ESC, we believe that
given the relatively high cost of this technology, a mandatory standard
is necessary to maximize the safety benefits associated with electronic
stability control, and is consistent with the mandate arising out of
SAFETEA-LU.
In order to realize these benefits, we have tentatively decided to
require vehicles both to be equipped with an ESC system meeting
definitional requirements and to pass a dynamic test. The definitional
requirements specify the necessary elements of a stability control
system that would be capable of both effective oversteer and understeer
intervention. These requirements are necessary due to the extreme
difficulty in establishing a test adequate to ensure the desired level
of ESC functionality.\2\ The test is necessary to ensure that the ESC
system is robust and meets a level of performance at least comparable
to that of current ESC systems. These requirements are summarized
below.
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\2\ Without an equipment requirement, it would be almost
impossible to devise a single performance test that could not be met
through some action by the manufacturer other than providing an ESC
system. Even a battery of performance tests still might not achieve
our intended results, because although it might necessitate
installation of an ESC system, we expect that it would be unduly
cumbersome for both the agency and the regulated community.
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Consistent with the industry consensus definition of ESC
contained in the Society of Automotive Engineers (SAE) Surface Vehicle
Information Report J2564 (rev. June 2004), we are proposing to require
vehicles covered under the standard to be equipped with an ESC system
that:
(1) Augments vehicle directional stability by applying and
adjusting the vehicle's brakes individually to induce correcting yaw
torques to a vehicle;
(2) Is computer-controlled, with the computer using a closed-loop
algorithm \3\ to limit vehicle oversteer and to limit vehicle
understeer when appropriate;
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\3\ A ``closed-loop algorithm'' is a cycle of operations
followed by a computer that includes automatic adjustments based on
the result of previous operations or other changing conditions.

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(3) Has a means to determine vehicle yaw rate \4\ and to estimate
its sideslip \5\;
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\4\ ``Yaw rate'' means the rate of change of the vehicle's
heading angle measured in degrees/second of rotation about a
vertical axis through the vehicle's center of gravity.
\5\ ``Sideslip'' means the arctangent of the lateral velocity of
the center of gravity of the vehicle divided by the longitudinal
velocity of the center of gravity.
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(4) Has a means to monitor driver steering input, and
(5) Is operational over the full speed range of the vehicle (except
below a low-speed threshold where loss of control of the vehicle is
unlikely).
The proposed ESC system as defined above would also be
required to be capable of applying all four brakes individually and to
have an algorithm that utilizes this capability. The system would also
be required to be operational during all phases of driving, including
acceleration, coasting, and deceleration (including braking), and it
would be required to remain operational when the antilock brake system
or traction control system is activated.
We are also proposing to require vehicles covered under
the standard to meet a performance test that would satisfy the
standard's stability criteria and responsiveness criterion when
subjected to the Sine with Dwell steering maneuver test. This test
involves a vehicle coasting at an initial speed of 50 mph while a
steering machine steers the vehicle with a steering wheel pattern as
shown in Figure 2. The test maneuver is then repeated over a series of
increasing maximum steering angles. This test maneuver was selected
over a number of other alternatives, because we tentatively decided
that it has the most optimal set of characteristics, including severity
of the test, repeatability and reproducibility of results, and the
ability to address lateral stability and responsiveness (see section
V.B).
The maneuver is severe enough to produce spinout for most vehicles
without ESC. The stability criteria for the test measure how quickly
the vehicle stops turning after the steering wheel is returned to the
straight-ahead position. A vehicle that continues to turn for an
extended period after the driver steers straight is out of control,
which is what ESC is designed to prevent. The stability criteria are
expressed in terms of the percent of the peak yaw rate after maximum
steering that persists at a period of time after the steering wheel has
been returned to straight ahead. They require that the vehicle yaw rate
decrease to no more than 35 percent of the peak value after one second
and that it continues to drop to no more than 20 percent after 1.75
seconds. Since a vehicle that simply responds very little to steering
commands could meet the stability criteria, a minimum responsiveness
criterion is applied to the same test. It requires that the ESC-
equipped vehicle must move laterally at least 1.83 meters (half a 12
foot lane width) during the first 1.07 seconds after the initiation of
steering (a discontinuity in the steering pattern that is convenient
for timing a measurement).
Because the benefits of the ESC system can only be
realized if the system is functioning properly, we are proposing to
require a telltale be mounted inside the occupant compartment in front
of and in clear view of the driver and be identified by the symbol
shown for ``ESC Malfunction Telltale'' in Table 1 of FMVSS No. 101,
Controls and Displays. The ESC malfunction telltale would be required
to illuminate not more than two minutes after the occurrence of one or
more malfunctions that affect the generation or transmission of control
or response signals in the vehicle's ESC system. Such telltale must
remain continuously illuminated for as long as the malfunction(s)
exists, whenever the ignition locking system is in the ``On'' (``Run'')
position. (Vehicle manufacturers would be permitted to use the ESC
malfunction telltale in a flashing mode to indicate ESC operation.)
In certain circumstances, drivers may have legitimate
reasons to disengage the ESC system or limit its ability to intervene,
such as when the vehicle is stuck in sand/gravel or when the vehicle is
being run on a track for maximum performance. Accordingly, under this
proposal, vehicle manufacturers would be permitted to include a driver-
selectable switch that places the ESC system in a mode in which it
would not satisfy the performance requirements of the standard (e.g.,
``sport'' mode or full-off mode). However, if the vehicle manufacturer
chooses this option, it would be required to ensure that the ESC system
always returns to a mode that satisfies the requirements of the
standard at the initiation of each new ignition cycle, regardless of
the mode the driver had previously selected. The manufacturer would be
required to provide an ``ESC Off'' switch and a telltale that is
mounted inside the occupant compartment in front of and in clear view
of the driver and which is identified by the symbol shown for ``ESC
Off'' in Table 1 of FMVSS No. 101. Such telltale must remain
continuously illuminated for as long as the ESC is in a mode that
renders it unable to meet the performance requirements of the standard,
whenever the ignition locking system is in the ``On'' (``Run'')
position.
We are not proposing to require the ESC system to be
equipped with a roll stability control function (or a separate system
to that effect). Roll stability control systems involve relatively new
technology, and there is currently insufficient data to judge the
efficacy of such systems. However, the agency will continue to monitor
the development of roll stability control systems. Vehicle
manufacturers may supplement the ESC system we are proposing to require
with a roll stability control system/feature.

B. Leadtime and Phase-In

In order to provide the public with what are expected to be the
significant safety benefits of ESC systems as rapidly as possible,
NHTSA is proposing to require all light vehicles covered by this
standard to be equipped with a FMVSS No. 126-compliant ESC system by
September 1, 2011. We are proposing that compliance would commence on
September 1, 2008, which would mark the start of a three-year phase-in
period. Subject to the special provisions discussed below, the proposed
phase-in schedule for FMVSS No. 126 would be as follows: 30 percent of
a vehicle manufacturer's light vehicles manufactured during the period
from September 1, 2008 to August 31, 2009 would be required to comply
with the standard; 60 percent of those manufactured during the period
from September 1, 2009 to August 31, 2010; 90 percent of those
manufactured during the period from September 1, 2010 to August 31,
2011, and all light vehicles thereafter.
In general, we believe that it would be practicable for vehicle
manufacturers to meet the requirements of the phase-in discussed above.
We anticipate that vehicle manufacturers would be able to meet the
requirements of the proposed standard by installing ESC systems
currently in production, and most vehicle lines would likely experience
some level of redesign over the next four to five years, which would
provide an opportunity to incorporate an ESC system during the course
of the manufacturer's normal production cycle (see section VI for a
more complete discussion).
However, NHTSA is proposing to exclude multi-stage manufacturers
and alterers from the requirements of the phase-in and to extend by one
year the time for compliance by those manufacturers (i.e., until
September 1, 2012). This NPRM also proposes to exclude small volume
manufacturers

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(i.e., manufacturers producing less than 5,000 vehicles for sale in the
U.S. market in one year) from the phase-in, instead requiring such
manufacturers to fully comply with the standard on September 1, 2011.
Under our proposal, vehicle manufacturers would be permitted to
earn carry-forward credits for compliant vehicles, produced in excess
of the phase-in requirements, which are manufactured between the
effective date of the final rule and the conclusion of the phase-in
period.\6\
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\6\ We note that carry-forward credits would not be permitted to
be used to defer the mandatory compliance date of September 1, 2011
for all covered vehicles.
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C. Anticipated Impacts of the Proposal

As noted above, we believe that ESC has among the highest life-
saving potential of any vehicle safety device developed in the past
three decades, ranking with seatbelts and air bags in terms of
importance. NHTSA estimates that ESC would save 5,300 to 10,300 lives
and prevent 168,000 to 252,000 injuries in all types of crashes annuvly
if all light vehicles on the road were equipped with ESC systems. A
large portion of these savings would come from rollover crashes. ESC
systems would substantially reduce (by 4,200 to 5,400) of the more than
10,000 deaths each year on American roads resulting from rollover
crashes.
About 29 percent of model year (MY) 2006 light vehicles sold in the
U.S. were equipped with ESC, and manufacturers intend to increase the
number of ESC installations in light vehicles to 71 percent by MY
2011.\7\ This rule would require a 100 percent installation rate for
ESC by MY 2012 (with exceptions for some vehicles manufactured in
stages or by small volume manufacturers). As the discussion below
demonstrates, ESC has very significant life-saving and injury-
preventing potential in absolute terms, but it does so in a very cost-
effective manner vis-a-vis other agency rulemakings. ESC offers
consistently strong benefits and cost-effectiveness across all types of
light vehicles, including passenger cars, SUVs, vans, and pick-up
trucks.
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\7\ In April 2006, NHTSA sent letters to seven vehicle
manufacturers requesting voluntary submission of information
regarding their planned production of ESC-equipped vehicles for
model years 2007 to 2012. Manufacturers responded with product plans
containing confidential information. These agency letters and
manufacturer responses (with confidential information redacted) may
be found in the docket for this rulemaking.
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Of the 5,300 to 10,300 highway deaths and 168,000 to 252,000 MAIS
1-5 injuries which we project will be prevented annually for all types
of crashes once all light vehicles on the road are equipped with ESC,
we would attribute 1,536 to 2,211 prevented fatalities (including 1,161
to 1,445 involving rollover) to this proposed rulemaking, in addition
to the prevention of 50,594 to 69,630 injuries. This compares favorably
with the Regulatory Impact Analyses for other important rulemakings
such as FMVSS No. 208 mandatory air bags (1,964 to 3,670 lives saved),
FMVSS No. 214 side impact protection (690 to 1,030 lives saved), and
FMVSS No. 201 upper interior head impact protection (870 to 1,050 lives
saved). (See section VII, Benefits and Costs of this notice and the
Preliminary Regulatory Impact Analysis submitted to the docket for this
rulemaking). In addition, the agency estimates that property damage and
travel delay costs would be reduced by $260 to $453 million annually.
The agency estimates that the production-weighted, average cost per
vehicle to meet the proposed standard's requirements would be $58
($90.3 per passenger car and $29.2 per light truck). These are
incremental costs over the MY 2011 installation of ABS, which is
expected to be installed in almost 93 percent of the light vehicle
fleet, and ESC, which is expected to be installed in 71 percent of the
light vehicle fleet. Vehicle costs are estimated to be $368 (in 2005$)
for anti-lock brakes (ABS) and an additional $111 for ESC, for a total
system cost of $479 per vehicle. Currently, every vehicle that is
equipped with ESC, is also equipped with ABS and traction control.
However, the agency believes that traction control is a convenience
feature. Accordingly, it is not required by this proposal. We also
assumed an annual production of 17 million light vehicles (9 million
light trucks and 8 million passenger cars). Thus, the total annual
vehicle cost of this regulation, corresponding to ESC installation
beyond manufacturers' planned production, is expected to be
approximately $985 million.
In terms of cost-effectiveness, this proposal for passenger cars
and light trucks would save 1,536 to 2,211 lives and prevent 50,594 to
69,630 injuries at a cost of $0.19 to $0.32 million per equivalent life
saved at a 3 percent discount rate and $0.27 to $0.43 at a 7 percent
discount rate. Again, the cost-effectiveness for ESC compares favorably
with the Regulatory Impact Analyses for other important rulemakings
such as FMVSS No. 202 head restraints safety improvement ($2.61 million
per life saved), FMVSS No. 208 center seat shoulder belts ($3.39 to
$5.92 million per life saved), FMVSS No. 208 advanced air bags ($1.9 to
$9.0 million per life saved), and FMVSS No. 301 fuel system integrity
upgrade ($1.96 to $5.13 million per life saved).
We note that the costs for passenger cars are higher because a
greater portion of those vehicles require installation of ABS in
addition to ESC. Nevertheless, the proposal remains highly cost-
effective even when passenger cars are considered alone. The passenger
car portion of the proposal would save 956 lives and prevent 34,902
injuries at a cost of $0.35 million per equivalent life saved at a 3
percent discount rate and $0.47 at a 7 percent discount rate.
Therefore, the agency deemed it appropriate to make the proposed
standard applicable to all light vehicles, because such approach makes
sense from both a safety and cost standpoint.

II. Safety Problems Addressed by the Proposed Standard

Crash data studies conducted in the U.S., Europe and Japan indicate
that ESC is very effective in reducing single-vehicle crashes. Studies
of the behavior of ordinary drivers in critical situations using the
National Advanced Driving Simulator also show a very large reduction in
instances of loss of control when the vehicle is equipped with ESC.
Based on its crash data studies, NHTSA estimates that ESC will reduce
single vehicle crashes of passenger cars by 34 percent and single
vehicle crashes of SUVs by 59 percent. NHTSA's latest crash data study
also shows that ESC is most effective in reducing single-vehicle
crashes that result in rollover. ESC is estimated to prevent 71 percent
of passenger car rollovers and 84 percent of SUV rollovers in single
vehicle crashes. It is also estimated to reduce some multi-vehicle
crashes but at a much lower rate than its effect on single vehicle
crashes.

A. Single-Vehicle Crash and Rollover Statistics

About one in seven light vehicles involved in police-reported
crashes collide with something other than another vehicle. However, the
proportion of these single-vehicle crashes increases steadily with
increasing crash severity, and almost half of serious and fatal
injuries occur in single-vehicle crashes. We can describe the
relationship between crash severity and the number of vehicles involved
in the crash using information from the agency's crash data programs.
We limit our discussion here to light vehicles, which consist of (1)
passenger cars and (2) multipurpose passenger vehicles, trucks and
buses under 4,536

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kilograms (10,000 pounds) gross vehicle weight rating (GVWR).\8\
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\8\ For brevity, we use the term light trucks in this document
to refer to multipurpose passenger vehicles, such as vans, minivans,
and SUVs, trucks and buses under 4,536 kilograms (10,000 pounds)
GVWR.
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The 2000-2004 data from the National Automotive Sampling System
(NASS) Crashworthiness Data System (CDS) and 2004 data from the
Fatality Analysis Reporting System (FARS) were combined to estimate the
current target population for this rulemaking. It includes 28,252
people who were killed as occupants of light vehicles. Over half of
these (15,007) occurred in single-vehicle crashes. Of these, 8,460
occurred in rollovers. About 1.1 million injuries (AIS 1-5) occurred in
crashes that could be affected by ESC, almost 500,000 in single vehicle
crashes (of which almost half were in rollovers). Multi-vehicle crashes
that could be affected by ESC accounted for 13,245 fatalities and
almost 600,000 injuries.
Rollover crashes are complex events that reflect the interaction of
driver, road, vehicle, and environmental factors. We can describe the
relationship between these factors and the risk of rollover using
information from the agency's crash data programs.
According to 2004 data from FARS, 10,555 people were killed as
occupants in light vehicle rollover crashes, which represents 33
percent of all occupants killed that year in crashes. Of those, 8,567
were killed in single-vehicle rollover crashes. Seventy-four percent of
the people who died in single-vehicle rollover crashes were not using a
seat belt, and 61 percent were partially or completely ejected from the
vehicle (including 50 percent who were completely ejected). FARS shows
that 55 percent of light vehicle occupant fatalities in single-vehicle
crashes involved a rollover event.
Using data from the 2000-2004 NASS CDS files, we estimate that
280,000 light vehicles were towed from a police-reported rollover crash
each year (on average), and that 29,000 occupants of these vehicles
were seriously injured. Of these 280,000 light vehicle rollover
crashes, 230,000 were single-vehicle crashes. Sixty-two percent of
those people who suffered a serious injury in a single-vehicle tow-away
rollover crash were not using a seat belt, and 52 percent were
partially or completely ejected (including 41 percent who were
completely ejected). Estimates from NASS CDS indicate that 82 percent
of tow-away rollovers were single-vehicle crashes, and that 88 percent
(202,000) of the single-vehicle rollover crashes occurred after the
vehicle left the roadway. An audit of 1992-96 NASS CDS data showed that
about 95 percent of rollovers in single-vehicle crashes were tripped by
mechanisms such as curbs, soft soil, pot holes, guard rails, and wheel
rims digging into the pavement, rather than by tire/road interface
friction as in the case of untripped rollover events.

B. The Agency's Comprehensive Response to Rollover

As mentioned above, this proposal for ESC is part of the agency's
comprehensive plan to address the issue of vehicle rollover. The
following provides background on NHTSA's comprehensive plan to reduce
rollover crashes. In 2002, the agency formed an Integrated Project Team
(IPT) to examine the rollover problem and make recommendations on how
to reduce rollovers and improve safety when rollovers nevertheless
occur. In June 2003, based on the work of the team, the agency
published a report entitled, ``Initiatives to Address the Mitigation of
Vehicle Rollover.'' \9\ The report recommended improving vehicle
stability, ejection mitigation, roof crush resistance, as well as road
improvement and behavioral strategies aimed at consumer education.
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\9\ See Docket Number NHTSA 2003-14622-1.
---------------------------------------------------------------------------

Since then, the agency has been working to implement these
recommendations as part of it comprehensive agency plan for reducing
the serious risk of rollover crashes and the risk of death and serious
injury when rollover crashes do occur. It is evident that the most
effective way to reduce deaths and injuries in rollover crashes is to
prevent the rollover crash from occurring. This proposal to adopt a new
Federal motor vehicle safety standard for electronic stability control
systems is one part of that comprehensive agency plan.
Moreover, we note that the agency also published a notice of
proposed rulemaking in the Federal Register in August 2005, seeking to
upgrade our safety standard on roof crush resistance (FMVSS No. 216);
that notice, like the present one, contains an in-depth discussion of
the rollover problem and the countermeasures which the agency intends
to pursue as part of its comprehensive response to the rollover problem
(see 70 FR 49223 (August 23, 2005)).

III. Electronic Stability Control Systems

Although Electronic Stability Control (ESC) systems are known by
many different trade names such as Vehicle Stability Control (VSC),
Electronic Stability Program (ESP), StabiliTrak and Vehicle Stability
Enhancement (VSE), their function and performance are similar. They are
systems that uses computer control of individual wheel brakes to help
the driver maintain control of the vehicle during extreme maneuvers by
keeping the vehicle headed in the direction the driver is steering even
when the vehicle nears or reaches the limits of road traction.
When a driver attempts an ``extreme maneuver'' (e.g., one initiated
to avoid a crash or due to misjudgment of the severity of a curve), the
driver may lose control if the vehicle responds differently as it nears
the limits of road traction than it does during ordinary driving. The
driver's loss of control can result in either the rear of the vehicle
``spinning out'' or the front of the vehicle ``plowing out.'' As long
as there is sufficient road traction, a highly skilled driver may be
able to maintain control in many extreme maneuvers using
countersteering (i.e., momentarily turning away from the intended
direction) and other techniques. However, average drivers in a panic
situation in which the vehicle beginning to spin out would be unlikely
to countersteer to regain control.
ESC uses automatic braking of individual wheels to adjust the
vehicle's heading if it departs from the direction the driver is
steering. Thus, it prevents the heading from changing too quickly
(spinning out) or not quickly enough (plowing out). Although it cannot
increase the available traction, ESC affords the driver the maximum
possibility of keeping the vehicle under control and on the road in an
emergency maneuver using just the natural reaction of steering in the
intended direction.
Keeping the vehicle on the road prevents single-vehicle crashes,
which are the circumstances that lead to most rollovers. However, if
the speed is simply too great for the available road traction, even a
vehicle with ESC will unavoidably drift off the road (but not spin
out). Furthermore, ESC cannot prevent road departures due to driver
inattention or drowsiness rather than loss of control.

A. How ESC Prevents Loss of Vehicle Control

The following explanation of ESC operation illustrates the basic
principle of yaw stability control, but it does not attempt to explain
advanced refinements of the yaw control strategy described below that
use vehicle sideslip (lateral sliding that may not alter yaw rate) to
optimize performance on slippery pavements.

[[Page 54717]]

An ESC system maintains what is known as ``yaw'' (or heading)
control by determining the driver's intended heading, measuring the
vehicle's actual response, and automatically turning the vehicle if its
response does not match the driver's intention. However, with ESC,
turning is accomplished by applying counter torques from the braking
system rather than from steering input.
Speed and steering angle measurements are used to determine the
driver's intended heading. The vehicle response is measured in terms of
lateral acceleration and yaw rate by onboard sensors. If the vehicle is
responding in a manner corresponding to driver input, the yaw rate will
be in balance with the speed and lateral acceleration.
The concept of ``yaw rate'' can be illustrated by imaging the view
from above of a car following a large circle painted on a parking lot.
One is looking at the top of the roof of the vehicle and seeing the
circle. If the car starts in a heading pointed north and drives half
way around circle, its new heading is south. Its yaw angle has changed
180 degrees. If it takes 10 seconds to go half way around the circle,
the ``yaw rate'' is 180 degrees per 10 seconds or 18 deg/sec. If the
speed stays the same, the car is constantly rotating at a rate of 18
deg/sec around a vertical axis that can be imagined as piercing its
roof. If the speed is doubled, the yaw rate increases to 36 deg/sec.
While driving in a circle, the driver notices that he must hold the
steering wheel tightly to avoid sliding toward the passenger seat. The
bracing force is necessary to overcome the lateral acceleration that is
caused by the car following the curve. The lateral acceleration is also
measured by the ESC system. When the speed is doubled the lateral
acceleration increases by a factor of four if the vehicle follows the
same circle. There is a fixed physical relationship between the car's
speed, the radius of its circular path, and its lateral acceleration.
The ESC system uses this information as follows: Since the ESC
system measures the car's speed and its lateral acceleration, it can
compute the radius of the circle. Since it then has the radius of the
circle and the car's speed, the ESC system can compute the correct yaw
rate for a car following the path. Of course, the system includes a yaw
rate sensor, and it compares the actual measured yaw rate of the car to
that computed for the path the car is following. If the computed and
measured yaw rates begin to diverge as the car that is trying to follow
the circle speeds up, it means the driver is beginning to lose control,
even if the driver cannot yet sense it. Soon, an unassisted vehicle
would have a heading significantly different from the desired path and
would be out of control either by oversteering (spinning out) or
understeering.
When the ESC system detects an imbalance between the measured yaw
rate of a vehicle and the path defined by the vehicle's speed and
lateral acceleration, the ESC system automatically intervenes to turn
the vehicle. The automatic turning of the vehicle is accomplished by
uneven brake application rather than by steering wheel movement. If
only one wheel is braked, the uneven brake force will cause the
vehicle's heading to change. Figure 1 shows the action of ESC using
single wheel braking to correct the onset of oversteering or
understeering. (Please note that all Figures discussed in this preamble
may be found at the end of the preamble, immediately preceding the
proposed regulatory text.)
Oversteering. In Figure 1 (bottom panel), the vehicle has
entered a left curve that is extreme for the speed it is traveling. The
rear of the vehicle begins to slide which would lead to a vehicle
without ESC turning sideways (or ``spinning out'') unless the driver
expertly countersteers. In a vehicle equipped with ESC, the system
immediately detects that the vehicle's heading is changing more quickly
than appropriate for the driver's intended path (i.e., the yaw rate is
too high). It momentarily applies the right front brake to turn the
heading of the vehicle back to the correct path. The action happens
quickly so that the driver does not perceive the need for steering
corrections. Even if the driver brakes because the curve is sharper
than anticipated, the system is still capable of generating uneven
braking if necessary to correct the heading.
Understeering. Figure 1 (top panel) shows a similar
situation faced by a vehicle whose response as it nears the limits of
road traction is to slide at the front (``plowing out'' or
understeering) rather than oversteering. In this situation, the ESC
system rapidly detects that the vehicle's heading is changing less
quickly than appropriate for the driver's intended path (i.e., the yaw
rate is too low). It momentarily applies the left rear brake to turn
the heading of the vehicle back to the correct path.
While Figure 1 may suggest that particular vehicles go out of
control as either vehicles prone to oversteer or vehicles prone to
understeer, it is just as likely that a given vehicle could require
both understeer and oversteer interventions during progressive phases
of a complex avoidance maneuver such as a double lane change.
Although ESC cannot change the tire/road friction conditions the
driver is confronted with in a critical situation, there are clear
reasons to expect it to reduce loss-of-control crashes, as discussed
below.
In vehicles without ESC, the response of the vehicle to steering
inputs changes as the vehicle nears the limits of road traction. All of
the experience of the average driver is in operating the vehicle in its
``linear range'', i.e., the range of lateral acceleration in which a
given steering wheel movement produces a proportional change in the
vehicle's heading. The driver merely turns the wheel the expected
amount to produce the desired heading. Adjustments in heading are easy
to achieve because the vehicle's response is proportional to the
driver's steering input, and there is very little lag time between
input and response. The car is traveling in the direction it is
pointed, and the driver feels in control. However, at lateral
accelerations above about one-half ``g'' on dry pavement for ordinary
vehicles, the relationship between the driver's steering input and the
vehicle's response changes (toward oversteer or understeer), and the
lag time of the vehicle response can lengthen. When a driver encounters
these changes during a panic situation, it adds to the likelihood that
the driver will loose control and crash because the familiar actions
learned by driving in the linear range would not be the correct
steering actions.
However, ordinary linear range driving skills are much more likely
to be adequate for a driver of a vehicle with ESC to avoid loss of
control in a panic situation. By monitoring yaw rate and sideslip, ESC
can intervene early in the impending loss-of-control situation with the
appropriate brake forces necessary to restore yaw stability before the
driver would attempt an over correction or other error. The net effect
of ESC is that the driver's ordinary driving actions learned in linear
range driving are the correct actions to control the vehicle in an
emergency. Also, the vehicle will not change its heading from the
desired path in a way that would induce further panic in a driver
facing a critical situation. Studies using a driving simulator,
discussed in Section IV, demonstrate that ordinary drivers are much
less likely to lose control of a vehicle with ESC when faced with a
critical situation.
Besides allowing drivers to cope with emergency maneuvers and
slippery pavement using only ``linear range'' skills, ESC provides more
powerful

[[Page 54718]]

control interventions than those available to even expert drivers of
non-ESC vehicles. For all practical purposes, the yaw control actions
with non-ESC vehicles are limited to steering. However, as the tires
approach the maximum lateral force sustainable under the available
pavement friction, the yaw moment generated by a given increment of
steering angle is much less than at the low lateral forces occurring in
regular driving.\10\. This means that as the vehicle approaches its
maximum cornering capability, the ability of the steering system to
turn the vehicle is greatly diminished, even in the hands of an expert
driver. ESC creates the yaw moment to turn the vehicle using braking at
an individual wheel rather than the steering system. This intervention
remains powerful even at limits of tire traction because both the
braking force of the individual tire and the reduction of lateral force
that accompanies the braking force act to create the desired yaw
moment. Therefore, ESC can be especially beneficial on slippery
surfaces. While a vehicle's possibility of staying on the road in a
critical maneuver ultimately is limited by the tire/pavement friction,
ESC maximizes an ordinary driver's ability to use the available
friction.
---------------------------------------------------------------------------

\10\ Liebemann et al., (2005) Safety and Performance
Enhancement: The Bosch Electronic Stability Control (ESP), 19th
International Technical Conference on the Enhanced Safety of
Vehicles (ESV), Washington, DC.
---------------------------------------------------------------------------

B. Additional Features of Some ESC Systems

In addition to the basic operation of ``yaw stability control'',
many ESC systems include additional features. For example, most systems
reduce engine power during intervention to slow the vehicle and give it
a better chance of being able to stay on the intended path after its
heading has been corrected.
Other ESC systems may go further by performing high deceleration
automatic braking at all four wheels. Of course, such braking would be
performed unevenly side to side so that the same net yaw torque or
``turning force'' would be applied to the vehicle as in the basic case
of single-wheel braking.
ESC systems used on vehicles with a high center of gravity (c.g.),
such as SUVs, are often programmed to perform an additional function
known as ``roll stability control.'' Roll stability control (RSC) is a
direct countermeasure for on-pavement rollover crashes of high c.g.
vehicles. Some RSC systems measure the roll angle of the vehicle using
an additional roll rate sensor to determine if the vehicle is in danger
of tipping up. Other systems rely on the existing ESC sensors for
steering angle, speed, and lateral acceleration, along with knowledge
of vehicle-specific characteristics to estimate whether the vehicle is
in danger of tipping up.
Regardless of the method used to detect the risk of tip-up, the
various types of roll stability control intervene in the same way.
Specifically, they intervene by reducing lateral acceleration which is
the cause of the roll motion of the vehicle on its suspension, thus
preventing the possibility of it rolling so much that the inside wheels
may lift off the pavement. The intervention is performed the same way
as the oversteer intervention shown in the Figure 1. The outside front
brake is applied heavily to turn the vehicle toward a path of less
curvature and, therefore, less lateral acceleration.
The difference between a roll stability control intervention and an
oversteer intervention by the ESC system operating in the basic yaw
stability control mode is the triggering circumstance. The oversteer
intervention occurs when the vehicle's excessive yaw rate indicates
that its heading is departing from the driver's intended path, but the
roll stability control intervention occurs when there is a risk the
vehicle could roll over. Thus, the roll stability control intervention
occurs when the vehicle is still following the driver's intended path.
The obvious trade-off of roll stability control is that the vehicle
must depart to some extent from the driver's intended path in order to
reduce the lateral acceleration from the level that could cause tip-up.
If the determination of impending rollover that triggers the roll
stability intervention is very certain, then the possibility of the
vehicle leaving the roadway as a result of the roll stability
intervention represents a lower relative risk to the driver. Obviously,
systems that intervene only when absolutely necessary and then with the
minimum loss of lateral acceleration to prevent rollover are the most
effective. However, roll stability control is a new technology that is
still evolving. Roll stability control is not a subject of this
rulemaking because it is too soon for actual crash statistics to
illuminate its practical effect on crash reduction.

IV. Effectiveness of ESC

Electronic stability control can directly reduce a vehicle's
susceptibility to on-road untripped rollovers as measured by the
``fishhook'' test that is part of NHTSA's NCAP rollover rating program.
The direct effect is mostly limited to untripped rollovers on paved
surfaces. However, untripped on-road rollovers are a relatively
infrequent type of rollover crash. In contrast, the vast majority of
rollover crashes occur when a vehicle runs off the road and strikes a
tripping mechanism such as soft soil, a ditch, a curb or a guardrail.
We expect that requiring ESC to be installed on light trucks and
passenger cars would result in a large reduction in the number of
rollover crashes by greatly reducing the number of single-vehicle
crashes. As noted previously, over 80 percent of rollovers are the
result of a single-vehicle crash. The purpose of ESC is to assist the
driver in keeping the vehicle on the road during impending loss-of-
control situations. In this way, it can prevent the exposure of
vehicles to off-road tripping mechanisms. We note, however, that this
yaw stability function of ESC is not direct ``rollover resistance'' and
cannot be measured by the NCAP rollover resistance rating.
Although ESC is an indirect countermeasure to prevent rollover
crashes, we believe it is the most powerful countermeasure available to
address this serious risk. Effectiveness studies by NHTSA and others
worldwide \11\ estimate that ESC reduces single vehicle crashes by at
least a third in passenger cars and perhaps reduces loss-of-control
crashes (e.g., road departures leading to rollovers) by an even greater
amount. In fact, NHTSA's latest data study that is discussed in this
section found a reduction in single-vehicle crashes leading to rollover
of 71 percent for passenger cars and 84 percent for SUVs. Thus, ESC can
reduce the numbers of rollovers of all vehicles, including lower center
of gravity vehicles (e.g., passenger cars, minivans and two-wheel drive
pickup trucks), as well as of the higher center of gravity vehicle
types (e.g., SUVs and four-wheel drive pickup trucks). ESC can affect
both crashes that would have resulted in rollover as well as other
types of crashes

[[Page 54719]]

(e.g., road departures resulting in impacts) that result in deaths and
injuries.

A. Human Factors Study on the Effectiveness of ESC
---------------------------------------------------------------------------

\11\ Aga M, Okada A. (2003) Analysis of Vehicle Stability
Control (VSC)'s Effectiveness from Accident Data, 18th International
Technical Conference on the Enhanced Safety of Vehicles (ESV),
Nagoya.
Dang, J. (2004) Preliminary Results Analyzing Effectiveness of
Electronic Stability Control (ESC) Systems, Report No. DOT HS 809
790. U.S. Dept. of Transportation, Washington, DC.
Farmer, C. (2004) Effect of Electronic Stability Control on
Automobile Crash Risk, Traffic Injury Prevention Vol 5:317-325.
Kreiss J-P, et al. (2005) The Effectiveness of Primary Safety
Features in Passenger Cars in Germany. 19th International Technical
Conference on the Enhanced Safety of Vehicles (ESV), Washington, DC
Lie A., et al. (2005) The Effectiveness of ESC (Electronic
Stability Control) in Reducing Real Life Crashes and Injuries. 19th
International Technical Conference on the Enhanced Safety of
Vehicles (ESV), Washington, DC.
---------------------------------------------------------------------------

A study by the University of Iowa using the National Advanced
Driving Simulator demonstrated the effect of ESC on the ability of
ordinary drivers to maintain control in critical situations.\12\ A
sample of 120 drivers equally divided between men and women and between
three age groups (18-25, 30-40, and 55-65) was subjected to the
following three critical driving scenarios. The ``Incursion Scenario''
forced drivers to attempt a double lane change at high speed (65 mph
speed limit signs) by presenting them first with a vehicle that
suddenly backs into their lane from a driveway and then with another
vehicle driving toward them in the left lane. The ``Curve Departure
Scenario'' presented drivers with a constant radius curve that was
uneventful at the posted speed limit of 65 mph followed by another
curve that appeared to be similar but that had a decreasing radius that
was not evident upon entry. The ``Wind Gust Scenario'' presented
drivers with a sudden lateral wind gust of short duration that pushed
the drivers toward a lane of oncoming traffic. The 120 drivers were
further divided evenly between two vehicles, a SUV and a midsize sedan.
Half the drivers of each vehicle drove with ESC enabled, and half drove
with ESC disabled.
---------------------------------------------------------------------------

\12\ Papelis et al. (2004) Study of ESC Assisted Driver
Performance Using a Driving Simulator, Report No. N04-003-PR,
University of Iowa.
---------------------------------------------------------------------------

In 50 of the 179 test runs performed in a vehicle without ESC, the
driver lost control. In contrast, in only six of the 179 test runs
performed in a vehicle with ESC, did the driver lose control. One test
run in each ESC status had to be aborted. These results demonstrate an
88 percent reduction in loss-of-control crashes when ESC was engaged.
The study also concluded that the presence of an ESC system helped
reduce loss of control regardless of age or gender, and that the
benefit was substantially the same for the different driver subgroups
in the study. Because of the obvious danger to participants, an
experiment like this cannot be performed safely with real vehicles on
real roads. However, the National Advanced Driver Simulator provides
extraordinary verisimilitude with the driver sitting in a real vehicle,
seeing a 360-degree scene and experiencing the linear and angular
accelerations and sounds that would occur in actual driving of the
specific vehicle.

B. Crash Data Studies of ESC Effectiveness

There have been a number of studies of ESC effectiveness in Europe
and Japan beginning in 2003 \13\. All of them have shown large
potential reductions in single vehicle crashes as a result of ESC.
However, the sample sizes of crashes of vehicles new enough to have ESC
tended to be small in these studies. A preliminary NHTSA study
published in September 2004 \14\ of crash data from 1997-2003 found ESC
to be effective in reducing single-vehicle crashes, including rollover.
Among vehicles in the study, the results suggested that ESC reduced
single vehicle crashes in passenger cars by 35 percent and in SUVs by
67 percent. In October 2004, the Insurance Institute for Highway Safety
(IIHS) released the results of a study of the effectiveness of ESC in
preventing crashes of cars and SUVs. The IIHS found that ESC is most
effective in reducing fatal single-vehicle crashes, reducing such
crashes by 56 percent. NHTSA's later peer-reviewed study \15\ of ESC
effectiveness found that that ESC reduced single vehicle crashes in
passenger cars by 34 percent and in SUVs by 59 percent, and that its
effectiveness was greatest in reducing single vehicle crashes resulting
in rollover (71 percent reduction for passenger cars and an 84 percent
reduction for SUVs). It also found reductions in fatal single-vehicle
crashes and fatal single-vehicle rollover crashes that were
commensurate with the overall crash reductions cited. ESC reduced fatal
single-vehicle crashes in passenger cars by 35 percent and in SUVs by
67 percent and reduced fatal single-vehicle crashes involving rollover
by 69 percent in passenger cars and 88 percent in SUVs.
---------------------------------------------------------------------------

\13\ See Footnote 10.
\14\ Dang, J. (2004) Preliminary Results Analyzing Effectiveness
of Electronic Stability Control (ESC) Systems, Report No. DOT HS 809
790. U.S. Dept. of Transportation, Washington, DC.
\15\ Dang, J. (2006) Statistical Analysis of The Effectiveness
of Electronic Stability Control (ESC) Systems, U.S. Dept. of
Transportation, Washington, DC (publication pending peer review). A
draft version of this report, as supplied to peer reviewers, has
been placed in the docket for this rulemaking.
---------------------------------------------------------------------------

(a) NHTSA's Preliminary Study
In September, 2004, NHTSA issued an evaluation note on the
Preliminary Results Analyzing the Effectiveness of Electronic Stability
Control (ESC) Systems. The study evaluated the effectiveness of ESC in
reducing single vehicle crashes in various domestic and imported cars
and SUVs. It was based on Fatality Analysis Reporting System (FARS)
data from calendar years 1997-2003 and crash data from five States that
reported partial Vehicle Identification Number (VIN) information in
their data files (Florida, Illinois, Maryland, Missouri, and Utah) from
calendar years 1997-2002. The data were limited to mostly luxury
vehicles because ESC first became available in 1997 in luxury vehicles
such as Mercedes-Benz and BMW. The analysis compared specific make/
models of passenger cars and SUVs with ESC versus earlier versions of
the same make/models, using multi-vehicle crash involvements as a
control group.
The passenger car sample consisted of mainly Mercedes-Benz and BMW
models (61 percent). Mercedes-Benz installed ESC in certain luxury
models in 1997 and had made it standard equipment in all their models
(except one) by 2000. BMW also installed ESC in certain 5, 7, and 8
series models as early as 1997 and had made it standard equipment in
all their models by 2001. The passenger car sample also included some
luxury GM cars, which constituted 23 percent of the sample, and a few
cars from other manufacturers. GM cars where ESC was offered as
standard equipment are the Buick Park Avenue Ultra, the Cadillac
DeVille, Seville STS and SLS, the Oldsmobile Aurora, the Pontiac
Bonneville SSE and SSEi, and the Chevrolet Corvette. The SUV make/
models in the study with ESC include Mercedes-Benz (ML320, ML350,
ML430, ML500, G500, G55 AMG), Toyota (4Runner, Landcruiser), and Lexus
(RX300, LX470).
The first set of analyses used multi-vehicle crash involvements as
a control group, essentially assuming that ESC has no effect on multi-
vehicle crashes. Specific make/models with ESC were compared with
earlier versions of similar make/models using multi-vehicle crash
involvements as a control group, creating 2x2 contingency tables as
shown in Tables 1 and 2. The study found that single vehicle crashes
were reduced by

1 - {(699/1483)/(14090/19444){time} = 35 percent

for passenger cars and by 67 percent for SUVs (Table 1). Similarly,
fatal single vehicle crashes were reduced by 30 percent in cars and by
63 percent in SUVs (Table 2). Reductions of single vehicle crashes in
passenger cars and SUVs were statistically significant at the .01
level, as evidenced by chi-square statistics exceeding 6.64 in each 2x2
contingency table (Table 1). Reductions of fatal single vehicle crashes
are statistically significant at the .01 level in SUVs and at the .05
level in passenger

[[Page 54720]]

cars with chi-square statistic greater than 3.84 (Table 2).

Table 1.--Effectiveness of ESC in Reducing Single Vehicle Crashes in
Passenger Cars and SUVs
[Preliminary Study with 1997-2002 crash data from five States]
------------------------------------------------------------------------
Multi-Vehicle
Single Vehicle Crashes
Crashes (control
group)
------------------------------------------------------------------------
Passenger Cars:
No ESC....................... 1483................. 19444
ESC.......................... 699.................. 14090
Percent reduction in single 35%.................. ..............
vehicle crashes in passenger
cars with ESC.
Approximate 95 percent 29% to 41%........... ..............
confidence bounds.
Chi-square value............. 84.1................. ..............
SUVs:
No ESC....................... 512.................. 6510
ESC.......................... 95................... 3661
Percent reduction in single 67%.................. ..............
vehicle crashes in SUVs with
ESC.
Approximate 95 percent 60% to 74%........... ..............
confidence bounds.
Chi-square value............. 104.4................ ..............
------------------------------------------------------------------------

Table 2.--Effectiveness of ESC in Reducing Fatal Single Vehicle Crashes
in Passenger Cars and SUVs
[Preliminary Study with 1997-2003 FARS data]
------------------------------------------------------------------------
Fatal Multi-
Vehicle
Fatal Single Vehicle Crashes
Crashes (control
group)
------------------------------------------------------------------------
Passenger Cars:
No ESC....................... 186.................. 330
ESC.......................... 110.................. 278
Percent reduction in fatal 30%.................. ..............
single vehicle crashes in
passenger cars with ESC.
Approximate 95 percent 10% to 50%........... ..............
confidence bounds.
Chi-square value............. 6.0.................. ..............
SUVs:
No ESC....................... 129.................. 199
ESC.......................... 25................... 103
Percent reduction in fatal 63%.................. ..............
single vehicle crashes in
SUVs with ESC.
Approximate 95 percent 44% to 81%........... ..............
confidence bounds.
Chi-square value............. 16.1................. ..............
------------------------------------------------------------------------

(b) NHTSA's Updated Study
NHTSA has now updated and modified last year's report, extending it
to model year 1997-2004 vehicles--and to calendar year 2004 for the
FARS analysis and calendar year 2003 for the State data analysis.
Nevertheless, even as of 2004, a large proportion of the vehicles
equipped with ESC were still luxury vehicles. Moreover, only passenger
cars and SUVs had been equipped with ESC--no pickup trucks or minivans.
The state databases included crash cases from California (2001-
2003), Florida (1997-2003), Illinois (1997-2002), Kentucky (1997-2002),
Missouri (1997-2003), Pennsylvania (1997-2001, 2003), and Wisconsin
(1997-2003). The FARS database included fatal crash involvements from
calendar years 1997 to 2004. The extra year of exposure and the
availability of data from more states significantly increased the
sample size of crashes of vehicles with ESC. In the preliminary study,
the state crash database contained 699 single-vehicle crashes of cars
with ESC and 95 single-vehicle crashes of SUVs with ESC. The FARS
database contained 110 single-vehicle crashes of cars with ESC and 25
single-vehicle crashes of SUVs with ESC. For the updated study, the
state crash database contains 2,251 single-vehicle crashes of cars with
ESC and 553 single-vehicle crashes of SUVs with ESC, and the FARS
database of fatal single-vehicle crashes contains 157 and 47 crashes
respectively, for passenger cars and SUVs with ESC.
The larger sample of crashes in the updated study facilitated a new
analysis of the effectiveness of ESC on specific subsets of single-
vehicle crashes (SV run-off-road crashes and SV crashes resulting in
rollover). It also facilitated the use of a more focused control group
of crashes that were unlikely to be affected by ESC so that a new
analysis of the effect of ESC on multi-vehicle crashes could be
undertaken.
The basic analytical approach was to estimate the reduction of
crash involvements of the types that are most likely to have benefited
from ESC--relative to a control group of other types of crashes where
ESC is unlikely to have made a difference in the vehicle's involvement.
Crash types taken as the new control group (non-relevant involvements
because ESC would in almost all cases not have prevented the crash)
were crash involvements in which a vehicle:
(1) Was stopped, parked, backing up, or entering/leaving a parking
space prior to the crash,
(2) Traveled at a speed less than 10 mph,
(3) Was struck in the rear by another vehicle, or
(4) Was a non-culpable party in a multi-vehicle crash on a dry
road.
The types of crash involvements where ESC would likely or at least
possibly have an effect are:

[[Page 54721]]

(1) All single vehicle crashes, except those with pedestrians,
bicycles, or animals (SV crashes).
(2) Single vehicles crashes in which a vehicle ran off the road (SV
ROR) and hit a fixed object and/or rolled over.
(3) Single vehicles crashes in which a vehicle rolled over (SV
Rollover), mostly a subset of SV ROR.
(4) Involvements as a culpable party in a multi-vehicle crash on a
dry or wet road (MV Culpable).
(5) Collisions with pedestrians, bicycles, or animals (Ped, Bike,
Animal).
In the updated study we performed the state data analysis
separately for each state. Then we used the median of the estimates
from the seven states as the best indicator of the central tendency of
the data, and the variation of the seven states as a basis for judging
statistical significance and estimating confidence bounds. The results
of this analysis are presented in Table 3.

Table 3.--Updated Study--Mean Effectiveness of ESC in Reducing Crashes in Passenger Cars and SUVs Based on Separate Analyses of 1997-2003 Crash Data
From Seven States
--------------------------------------------------------------------------------------------------------------------------------------------------------
SV crashes SV ROR SV rollover MV culpable Ped, bike, animal
--------------------------------------------------------------------------------------------------------------------------------------------------------
Passenger Cars:
Mean percent reduction of 34%............. 46%............. 71%............. 11%............. 34%
listed crash type in
passenger cars with ESC.
Approximate 90 percent 20% to 46%...... 35% to 55%...... 60% to 78%...... 4% to 18%....... 5% to 55%.
confidence bounds.
SUVs:
Mean percent reduction of 59%............. 75%............. 84%............. 16%............. -4% not statistically significant.
listed crash type in SUVs
with ESC.
Approximate 90 percent 47% to 68%...... 68% to 80%...... 75% to 90%...... 7% to 24%....... -28% to 15%.
confidence bounds.
--------------------------------------------------------------------------------------------------------------------------------------------------------

Fatal crashes were analyzed separately using the FARS database as
was done in the preliminary study, but larger sample sizes were
possible because of an additional year of data. The results are given
in Table 4.

Table 4.--Updated Study-Effectiveness of ESC in Reducing Fatal Crashes of Passenger Cars and SUVs Based on 1997-2004 FARS Data
--------------------------------------------------------------------------------------------------------------------------------------------------------
SV crashes SV ROR SV rollover MV culpable Ped, bike, animal Control group
--------------------------------------------------------------------------------------------------------------------------------------------------------
Passenger Cars:
No ESC..................... 223................. 217................. 36.................. 176.............. 46............... 166
ESC........................ 157................. 154................. 12.................. 156.............. 69............... 181
Percent reduction of listed 35%................. 36%................. 69%................. 19% not -38% not ...............
crash type in passenger statistically statistically
cars with ESC. significant. significant.
Approximate 90 percent 20% to 51%.......... 19% to 51%.......... 52% to 87%.......... -2% to 39%....... -87% to 12%...... ...............
confidence bounds.
Chi-square value........... 8.58................ 8.17................ 12.45............... 1.82............. 2.14............. ...............
SUVs:
No ESC..................... 197................. 191................. 106................. 108.............. 56............... 153
ESC........................ 47.................. 38.................. 9................... 48............... 40............... 109
Percent reduction of listed 67%................. 72%................. 88%................. 38%.............. 0% not ...............
crash type in SUVs with statistically
ESC. significant.
Approximate 90 percent 55% to 78%.......... 62% to 82%.......... 81% to 95%.......... 16% to 60%....... -40% to 40%...... ...............
confidence bounds.
Chi-square................. 29.57............... 36.44............... 42.4................ 4.89............. 0.00............. ...............
--------------------------------------------------------------------------------------------------------------------------------------------------------

The effectiveness of ESC in reducing fatal single-vehicle crashes
is similar to the effectiveness in reducing single-vehicle crashes from
state data that included mostly non-fatal crashes. In the case of fatal
crashes as well, the effectiveness of ESC in reducing single-vehicle
rollover crashes was particularly high. The effectiveness of ESC in
reducing fatal culpable multi-vehicle crashes of SUVs was also higher
than in the analysis of state data, and the parallel analysis of multi-
vehicle crashes of passenger cars did not achieve statistical
significance.
The updated study of ESC effectiveness yielded robust results. The
analysis of state data and a separate analysis of fatal crashes both
reached similar conclusions on ESC effectiveness. ESC reduced single
vehicle crashes of passenger cars by 34 percent and single vehicle
crashes of SUVs by 59 percent. The separate analysis of only fatal
crashes supported the analysis of state data that included mostly non-
fatal crashes. Therefore, the overall crash reductions demonstrated a
significant life-saving potential for this technology. The
effectiveness of ESC in reducing SV crashes shown in the latest data
(Tables 3-4) is similar to the results of the preliminary analysis.

[[Page 54722]]

The effectiveness of ESC tended to be at least as great and
possibly even greater for more severe crashes. Furthermore, the
effectiveness of ESC in reducing the most severe type of crash in the
study, the single-vehicle rollover crash, was remarkable. ESC reduced
single-vehicle rollover crashes of passenger cars by 71 percent and of
SUVs by 84 percent. This high level of effectiveness also carried over
to fatal single-vehicle rollover crashes.
The benefits presented in Section VII were calculated on the basis
of the single-vehicle crash and single-vehicle rollover crash
effectiveness results of Table 3 for reductions in non-fatal crashes
and of Table 4 for reductions in fatal crashes. The single-vehicle
rollover crash effectiveness results were applied only to first harmful
event rollovers with the lower single-vehicle crash effectiveness
results applied to all other rollover crashes for a more conservative
benefit estimate.

V. Agency Proposal

As discussed in detail in section VII, NHTSA's crash data study
leads to the conclusion that an ESC requirement for light vehicles
would save 1,536 to 2,211 lives annually once all light vehicles have
ESC. The level of life saving associated with ESC would be second only
to seatbelts among the items of equipment or elements of design
regulated by the Federal motor vehicle safety standards. It is further
estimated that an ESC requirement would prevent between 50,594 and
69,630 MAIS 1-5 injuries annually. The life saving benefits of ESC are
considered very cost effective with a cost per equivalent fatality of
$0.19 million under the most favorable assumptions and $0.43 million
under the least favorable assumptions.
In order to capture these significant safety benefits NHTSA is
proposing to establish FMVSS No. 126, Electronic Stability Control
Systems, which would require passenger cars, light trucks and buses
that have a GVWR under 4,536 Kg (10,000 lbs) GVWR to be equipped with
an ESC system with a yaw stability control function equal to that of
vehicles in current production. The benefits demonstrated by NHTSA's
crash data studies and sought by the proposed safety standard are the
result of yaw stability control greatly reducing single-vehicle crashes
and reducing some multi-vehicle crashes as well. None of the study
vehicles was equipped with a roll stability control system. Thus, we
are proposing equipment requirements that are met by every ESC-equipped
vehicle in current production and performance requirements that we
believe are met by about 98 percent of ESC-equipped vehicles in current
production and will require nothing more than slight retuning of the
other two percent.
We are not proposing a roll stability control system because there
are no data currently available to determine the effect of roll
stability control on crashes. However, vehicle manufacturers may
supplement the proposed ESC systems with roll stability control.
As proposed, FMVSS No. 126 would incorporate both an equipment
requirement and a performance requirement. Specifically, we are
proposing an equipment requirement for ESC that would define the
necessary elements of a yaw stability control system capable of
effective oversteer and understeer interventions. The ESC equipment
requirement is augmented by a performance test of the system's
oversteer intervention. We believe that an equipment requirement is
necessary because establishing performance tests that would ensure that
the ESC system operates under all road conditions and phases of driving
is impractical. The number of tests would be immense, and many tests
(particularly those using slippery surfaces) would not be repeatable
enough for an objective regulation. A test requirement for understeer
mitigation is particularly problematic because the understeer
mitigation for many light trucks is programmed to occur only on
slippery surfaces to avoid potential roll instability.
The proposed standard includes a performance test of oversteer
intervention conducted with a single highly repeatable maneuver
performed on dry pavement over a range of steering angles with an
automated steering machine. It is designed to ensure that the
performance of the system is comparable to current production systems
under a limited set of conditions that are optimal for repeatable
testing, and it proves that the ESC system is programmed to perform its
most basic task under ideal conditions.
Most vehicles without ESC will spin out in this maneuver; so, a
vehicle that avoids spin-out according to our objective yaw rate decay
definition demonstrates that it has an ESC system typical of 2006
production vehicles. However, the maneuver is not so extreme that every
vehicle without ESC will actually spin out. A few non-ESC vehicles will
pass this particular maneuver test, however they would certainly spin
out on slippery surfaces. Therefore, the test without the definition
does not assure the safety benefits of ESC.
All model year 2006 vehicles with ESC systems would satisfy the
definitional requirements of the standard. Of the sixty-two ESC
vehicles tested by NHTSA or the Alliance of Automobile Manufacturers
(Alliance), whose test fleet supplemented NHTSA's, only one would need
minor reprogramming to pass the performance test.
Some of the older vehicles in NHTSA's crash data study would not
pass the proposed requirements (e.g., among the early ESC systems,
there were some that were not capable of understeer intervention).
Nevertheless, over 85 percent of the data in NHTSA's study represent
vehicles (1998-2003 model years) that we believe would satisfy the
proposed requirements of the new safety standard. The study vehicles
that did not satisfy the proposed standard had systems that were
beneficial but less effective than the average.

A. Definition of ESC

The Society of Automotive Engineers (SAE) Surface Vehicle
Information Report on Automotive Stability Enhancement Systems J2564
Rev JUN2004 provides an industry consensus definition of an ESC system.
The definition in paragraph 4.6 of SAE J2564 specifies that a ESC
system:

(a) Is computer controlled and the computer contains a closed-
loop algorithm \16\ designed to limit understeer and oversteer of
the vehicle.
---------------------------------------------------------------------------

\16\ A closed-loop algorithm is a cycle of operations followed
by a computer that includes automatic adjustments based on the
result of previous operations or other changing conditions.
---------------------------------------------------------------------------

(b) Has a means to determine vehicle yaw velocity and sideslip.
(c) Has a means to monitor driver steering input.
(d) Has a means of applying and adjusting the vehicle brakes to
induce correcting yaw torques to the vehicle.
(e) Is operational over the full speed range of the vehicle
(except below a low-speed threshold where loss of control is
unlikely).

We believe the SAE definition is a good basis for the proposed
equipment requirement but that it requires minor clarifications to
adequately describe current production systems. The definition that
NHTSA proposes contains changes in paragraphs (a) and (b). Paragraph
(a) has been changed to read: ``(a) is computer controlled with the
computer using a closed-loop algorithm to limit vehicle oversteer and
to limit vehicle understeer when appropriate.''

[[Page 54723]]

This change recognizes that while all current ESC systems
constantly limit oversteer, many of the systems used on vehicles with a
high center of gravity only limit understeer on slippery surfaces where
there is no danger that the understeer intervention could increase the
possibility of tip-up. We also changed the expression about the
``computer containing the algorithm'' to refer to the ``computer using
the algorithm'' to reduce ambiguity. Furthermore, we note that
``limiting'' understeer and oversteer means keeping those conditions
within bounds that allow ordinary drivers to maintain control of the
vehicle in critical situations. It does not mean reducing understeer
and oversteer to zero under all circumstances because that is an
impossibility, certainly not representative of production ESC systems.
Paragraph (b) has been changed to read: ``(b) has a means to
determine the vehicle's yaw rate and to estimate its side slip. A
distinction has been made between the ways yaw rate and side slip are
obtained.'' Current ESC systems use sensors to measure yaw rate,
constituting an actual determination of this crucial metric, but they
estimate rather than measure side slip.
Also, the term ``yaw velocity'' has been changed to ``yaw rate''
because that is the term used in our research reports. Both terms have
the same meaning.
The SAE document also defines four categories of ESC systems: Two
wheel and four wheel systems, each with or without engine control. The
minimum system capable of understeer and oversteer intervention is the
four-wheel system without engine control. SAE describes systems in this
category as having the following attributes:
(a) The system must have means to apply all four brakes
individually and a control algorithm, which utilizes this capability.
(b) The system must be operational during all phases of driving
including acceleration, coasting, and deceleration (including braking).
(c) The system must stay operational when ABS or Traction Control
are activated.
The proposed regulatory language would require an ESC system that
combines the SAE definition with the minor clarifications discussed and
the attributes of the four-wheel system without engine control. Nothing
in the regulatory language conflicts with systems that employ engine
control.
In addition, the proposed regulatory language supplements the ESC
equipment definition with a test of oversteer intervention which would
define the minimum intensity of the oversteer intervention under
certain test conditions. The test is performed with the vehicle
coasting on a dry pavement with a high coefficient of friction. The
test conditions are very narrow in comparison with the operational
conditions specified in the equipment definition, but they are
necessary to produce a practical test with the high level of
repeatability. The performance test specifies a severe steering regime
that would produce oversteer loss of control in nearly every vehicle
without a modern ESC system, and it specifies a maximum time for the
vehicle to cease its yaw motion after the steering returns to straight
ahead.
At this time, we cannot propose a similar test of the intensity of
the ESC system's understeer intervention. Typically, systems on
vehicles with high centers of gravity do not perform understeer
intervention on dry surfaces because that could increase the
possibility of an on-road untripped rollover. In such case, attempting
to maintain the driver's desired path would increase lateral
acceleration and roll moment. In fact, roll stability control works by
inducing high levels of understeer when required to prevent tip-up.
Therefore, tests of understeer intervention must be performed on low
coefficient surfaces to avoid prohibiting roll stability control
systems. Unfortunately, the regular methods of producing wet, slippery,
or icy conditions at automotive proving grounds are useful only for
such purposes as back-to-back comparisons of vehicles because
repeatable friction conditions cannot be maintained or precisely
reproduced. A practical test of understeer intervention is a topic of
ongoing research.

B. Performance Test of ESC Oversteer Intervention and Stability
Criteria

Selection of Maneuver
NHTSA performed research to define a practical, repeatable and
realistic maneuver test of ESC oversteer intervention. We also made use
of the results of testing performed by the Alliance on some candidate
maneuvers to supplement the agency's information. NHTSA's detailed
research report \17\ has been placed in the docket, and this section
represents a summary of its major points.
---------------------------------------------------------------------------

\17\ Forkenbrock, G. et al. (2005) Development of Criteria for
Electronic Stability Control Performance Evaluation, DOT HS 809 974.
---------------------------------------------------------------------------

The desired test should discriminate strongly between vehicles with
and without ESC. Vehicles with ESC disabled were used as non-ESC
vehicles in the research. It must also facilitate the evaluation of
both the lateral stability of the vehicle (prevention of spinout) and
its responsiveness in avoiding obstacles on the road, since stability
can be gained at the expense of responsiveness. The research program
consisted of two phases:
Phase 1: The evaluation of many maneuvers capable of quantifying
the performance of ESC oversteer intervention using a small sample of
diverse test vehicles.
Phase 2: Evaluation of many vehicles using a reduced suite of
candidate maneuvers.
Phase 1 testing occurred during the period of April through October
2004. In this effort, twelve maneuvers were evaluated using five test
vehicles. Maneuvers utilized automated and driver-based steering
inputs. If driver-based steering was required, multiple drivers were
used to assess input variability. To quantify the effects of ESC, each
vehicle was evaluated with ESC enabled and disabled. Dry and wet
surfaces were utilized; however, the wet surfaces introduced an
undesirable combination of test variability and sensor malfunctions.
Table 5 summarizes the Phase 1 test matrix. Additional details
pertaining to Phase 1, including more detailed maneuver descriptions
and details pertaining to test conduct, have been previously
documented.\18\
---------------------------------------------------------------------------

\18\ Forkenbrock et al (2005) NHTSA's Light Vehicle Handling and
ESC Effectiveness Research Program, 19th International Technical
Conference on the Enhanced Safety of Vehicles (ESV), Washington, DC.

[[Page 54724]]

Table 5.--NHTSA's 2004 Light Vehicle Handling/ESC Test Matrix
------------------------------------------------------------------------
Test group 1 Test group 2 Test group 3
------------------------------------------------------------------------
Slowly Increasing Steer .................. Closing
Radius Turn.
NHTSA J-Turn (Dry, Wet) Modified Pulse
ISO 3888-22. Steer (500 deg/s,
700 deg/s).
NHTSA Fishhook (Dry, Constant Sine
Wet). Radius Turn. Steer (0.5 Hz,
0.6 Hz, 0.7 Hz,
0.8 Hz).

Increasing
Amplitude Sine
Steer (0.5 Hz,
0.6 Hz, 0.7 Hz.
Sine with
Dwell (0.5 Hz,
0.7 Hz).
Yaw
Acceleration
Steering Reversal
(YASR) (500 deg/
s, 720 deg/s).

Increasing
Amplitude YASR
(500 deg/s, 720
deg/s).
------------------------------------------------------------------------

To determine whether a particular test maneuver was capable of
providing a good assessment of ESC performance, NHTSA considered the
extent to which it possessed three attributes:
1. A high level of severity that would exercise the oversteer
intervention of every vehicle's ESC system.
2. A high level of repeatability and reproducibility.
3. The ability to assess both lateral stability and responsiveness.
Phase 2 testing examined the four maneuvers that were considered
most promising from Phase 1: (1) Sine with Dwell; (2) Increasing
Amplitude Sine Steer; (3)Yaw Acceleration Steering Reversal (YASR); and
(4) YASR with Pause.\19\ The two yaw acceleration steering reversal
maneuvers were designed to overcome the possibility that fixed-
frequency steering maneuvers would discriminate on the basis of vehicle
properties other than ESC performance, such as wheelbase length. They
were more complex than the other maneuvers, requiring the automated
steering machines to trigger on yaw acceleration peaks. However, Phase
2 research revealed an absence of effects of yaw natural frequency.
Therefore, the YASR maneuvers were dropped from further consideration
because their increased complexity was not warranted in light of
equally effective but simpler alternatives, and their details will not
be discussed in this summary of NHTSA research. Additional detail on
the remaining maneuvers is presented below:
---------------------------------------------------------------------------

\19\ Ibid.

---------------------------------------------------------------------------
Sine With Dwell

As shown in Figure 2, the Sine with Dwell maneuver was based on a
single cycle of sinusoidal steering input. Although the peak magnitudes
of the first and second half-cycles were identical, the Sine with Dwell
maneuver included a 500 ms pause after completion of the third quarter-
cycle of the sinusoid. In Phase 1, frequencies of 0.5 and 0.7 Hz were
used. In Phase 2, only 0.7 Hz Sine with Dwell maneuvers were performed.
As described in NHTSA's report,\20\ the 0.7 Hz frequency was found to
be consistently more severe than its 0.5 Hz counterpart (in the context
of this research, severity was quantified by the amount of steering
wheel angle required to produce a spinout). In Phase 1, the 0.7 Hz Sine
with Dwell was able to produce spinouts with lower steering wheel
angles for four of the five vehicles evaluated, albeit by a small
margin (no more than 20 degrees of steering wheel angle for any
vehicle).
---------------------------------------------------------------------------

\20\ Forkenbrock, G. et al. (2005) Development of Criteria for
Electronic Stability Control Performance Evaluation, Dot HS 809 974.
---------------------------------------------------------------------------

In a presentation \21\ given to NHTSA on December 3, 2004, the
Alliance also reported that the 0.5 Hz Sine with Dwell did not
correlate as well with the responsiveness versus controllability
ratings made by its professional test drivers in a subjective
evaluation (the same vehicles evaluated with the Sine with Dwell
maneuvers were also driven by the test drivers), and it provided less
input energy than the 0.7 Hz Sine with Dwell.
---------------------------------------------------------------------------

\21\ Docketed at NHTSA-2004-19951, item 1.
---------------------------------------------------------------------------

Increasing Amplitude Sine

As shown in Figure 3, the Increasing Amplitude Sine maneuver was
also based on a single cycle of sinusoidal steering input. However, the
amplitude of the second half-cycle was 1.3 times greater than the first
half-cycle for this maneuver. In Phase 1, frequencies of 0.5, 0.6, and
0.7 Hz were used for the first half cycle; the duration of the second
half cycle was 1.3 times that of the first.
The Phase 1 vehicles were generally indifferent to the frequency
associated with the Increasing Amplitude Sine maneuver. Given our
desire to reduce the test matrix down from three maneuvers based on
three frequencies to one, NHTSA selected just the 0.7 Hz frequency
Increasing Amplitude Sine for use in Phase 2. In the previously
mentioned presentation given to NHTSA on December 3, 2004, the Alliance
also reported that the 0.6 Hz Increasing Amplitude Sine did not induce
vehicle responses significantly different than the 0.5 and 0.7 Hz
Increasing Amplitude Sine maneuvers.
To select the best overall maneuver from those used in Phase 2,
NHTSA considered three attributes: (1) Maneuver severity, (2) face
validity, and (2) performability. Of the two sinusoidal maneuvers used
in Phase 2, we determined that the Sine with Dwell was the best
candidate for evaluating the lateral stability component of ESC
effectiveness because of its relatively greater severity. Specifically,
it required a smaller steering angle to produce spinouts (for test
vehicles with ESC disabled). Also, the Increasing Amplitude Sine
maneuver produced the lowest yaw rate peak magnitudes in proportion to
the amount of steering, implying the maneuver was the least severe for
most vehicles evaluated by NHTSA in Phase 2.
The performability of the Sine with Dwell and Increasing Amplitude
Sine maneuvers is excellent. The maneuvers are very easy to program
into the steering machine, and their lack of rate or acceleration
feedback loops simplifies the instrumentation required to perform the
tests. As mentioned previously, Phase 2 testing revealed that the extra
complexity of YASR maneuvers was unnecessary because the tests were not
affected by yaw natural frequency differences between vehicles.
All Phase 2 maneuvers (including the YASR maneuvers) possess an
inherently high face validity because they are each comprised of
steering inputs similar to those capable of being produced by a human
driver in an emergency obstacle avoidance maneuver. However, the
Increasing Amplitude Sine maneuver may possess the best face validity.
Conceptually, the steering profile of this maneuver is the most similar
to that expected to be used by real drivers, and even with steering
wheel angles as large

[[Page 54725]]

as 300 degrees, the maneuver's maximum effective steering rate is a
very reasonable 650 deg/sec.
In light of the above, NHTSA is proposing to use the Sine with
Dwell maneuver to evaluate the performance of light vehicle ESC systems
in preventing spinout (oversteer loss of control). On the balance we
believe that it offers excellent face validity and performability, and
its greater severity makes it a more rigorous test while maintaining
steering rates within the capabilities of human drivers.
Spinout Criteria
The foregoing maneuver selection process required a definition of
``spinout.'' Spinout can be best explained in the context of the Sine
with Dwell maneuver. Figure 4 shows the steering wheel angle driven by
a robotic steering machine during three runs of the maneuver at
increasing steering amplitudes and the resulting measurements of the
yaw rate of an actual vehicle being tested. The maneuver is the same as
that shown in Figure 2, except that the first steering is to the left
in Figure 4 while it is to the right in Figure 2.
The test protocol requires the test to be performed at an entrance
speed of 50 mph (coasting) in both directions at increasing steering
amplitudes up to a preset maximum or to the point at which the vehicle
spins out (failing the test). The preset maximum steering angle is the
larger of either 270 degrees or an angle equal to 6.5 times the
steering angle that produces 0.3g steady state lateral acceleration for
the particular test vehicle. This specification of maximum test
steering angle takes into account differences in steering gear ratio,
wheelbase, and other factors between vehicles, but provides for testing
to a steering wheel angle of at least 270 degrees. This maximum
steering wheel angle is not achieved in the event that the test is
terminated by spinout at a lower steering wheel angle.
As shown in Figure 4, in the first run, the steering wheel is
turned 80 degrees to the left, then 80 degrees to the right following a
smooth 0.7 Hz sinusoidal pattern. It is held steady for a dwell time of
0.5 second at 80 degrees right, and then returned to zero (straight
ahead) also following a sinusoidal pattern. After a short lag, the
vehicle begins to yaw counter-clockwise in response to the left
steering. The absolute value of the yaw velocity increases with the
absolute value of the steering angle, and then the vehicle changes to
clockwise yaw velocity in response to right steering. At two seconds
after the beginning of steering, the steering wheel has been turned
back to straight ahead, and the yaw rate returns to zero after a
fraction of a second response time. At that point, the vehicle is being
steered straight ahead, and it is going straight ahead without any yaw
rotation. The vehicle is responding closely to the steering input, and
the driver is in control.
When the steering amplitude is increased to 120 degrees in the next
run, the vehicle achieves greater yaw velocity because it is following
a tighter path at the same speed, but it exhibits the same good
response to steering and remains in control.
However, when the steering amplitude is increased to 169 degrees,
the vehicle spins out, exhibiting oversteer loss of control. This
condition is identified in the yaw rate trace. When the steering is
straight ahead at time = 2 seconds, the yaw rate for this run is still
about 35 deg/sec. However, there is a time lag past the instant of
steering to straight ahead even for the previous runs where there was
no loss of control. What is different is that the yaw rate does not
swiftly decline to zero as it does with a vehicle under control. At
time = 3 seconds, the yaw rate is still the same, and it has actually
increased at time = 4 seconds in this example. The physical
interpretation of this graph is that the driver has turned the wheels
straight ahead and wants the vehicle to go straight, but the vehicle is
spinning clockwise about a vertical axis through its center of gravity.
It is out of control in a spinout. The driver's steering input is not
causing the vehicle to take the desired path and heading, and the
vehicle would depart the road surface sideways or even backward.
Figure 4 illustrates that the Sine with Dwell Maneuver is very
severe. It induced a dramatic spinout in this test vehicle with only
169 degrees of steering to one direction followed by 169 degrees to the
other. It is possible that steering angles below 169 degrees but above
120 degrees would also have caused spinout. Since the test is
predicated on steering angles up to (or possibly exceeding) 270
degrees, it would cause spinout in vehicles with far greater lateral
stability than this test vehicle.
Figure 5 shows another series of tests of the same vehicle but with
ESC enabled. The first two runs were at 80 and 120 degrees of steering
angle, and the vehicle's yaw rate declined to zero in a fraction of a
second after the steering command. This is the same good response to
steering exhibited by the vehicle with ESC disabled in the previous
figure. The third run was conducted at 180 degrees of steering angle.
This is greater than the 169 degrees that caused a severe loss of
control without ESC, but the yaw rate returned to zero with the
steering angle just as quickly as in the runs with less steering.
The final set of curves in Figure 5 represent a run conducted with
279 degrees of steering angle. This would be the left-right portion of
the performance test proposed for the ESC system of this vehicle since
279 degrees is 6.5 times the steering angle that produces 0.3g steady
state lateral acceleration for this example vehicle. In this case, the
yaw rate did not return to zero nearly instantaneously as it had at
lower steering angle. Instead, it steadily declined after the steering
was turned to straight ahead, and the vehicle was completely stable and
going straight in about 1.75 seconds. Clearly, the vehicle remained in
control compared to its behavior without ESC (see Figure 4) in which
turning the steering to straight ahead had no effect on the vehicle's
heading. However, the ESC system required some time to cause the
vehicle to stop turning in response to the driver's straight ahead
steering command because the preceding maneuver was so destabilizing.
The time it takes for the vehicle to stop rotating after it is steered
straight ahead in this maneuver is a measure of the aggressiveness of
the ESC oversteer intervention. Some of the early ESC systems were
tuned to be less aggressive than the example vehicle, and the lag time
for the vehicle to ``recover'' from the Sine with Dwell Maneuver would
be longer.
The first goal of an ESC system is to prevent spinout, but there is
no hard quantitative definition of spinout. Obviously, the example in
Figure 4 shows spinout. The vehicle turned nearly front to rear in four
seconds with the steering wheel straight ahead. In the example of
Figure 5, the vehicle always responded to steering, but some response
time was required for it to fully stabilize. In seeking to define
``spinout'', the agency believes that the question is: How long must
the response time be before the result would be considered a spinout in
the severe test maneuver?
NHTSA used an empirical definition of spinout based on observations
from vehicle maneuver testing as a rule of thumb. This empirically-
based criterion stipulates that in a symmetric steer maneuver, in which
the amount of right and left steering is equal, if the final heading
angle is more than 90 degrees from the initial heading, the vehicle has
spun out. If a symmetric steer maneuver is performed at a very low
speed that

[[Page 54726]]

eliminates tire slippage, the heading does not change at all. However,
a change of heading of about 20 degrees would occur even at low speed
in the Sine with Dwell Maneuver because of the asymmetric dwell
portion, making this empirical criterion more conservative. NHTSA's
research report \22\ contains a statistical study on how quickly an ESC
system would have to respond to prevent a heading change of more than
90 degrees during the Sine with Dwell Maneuver at 50 mph with full
steering using data from all 40 vehicles tested by NHTSA and the
Alliance.
---------------------------------------------------------------------------

\22\ Forkenbrock, g. et al. (2005) Development of Criteria for
Electronic Stability Control Performance Evaluation, DOT HS 809 974
---------------------------------------------------------------------------

Two measures of response time were considered: (1) The remaining
yaw rate (as a percent of peak) one second after the steering wheel was
turned straight ahead, and (2) the remaining percent of peak yaw rate
after 1.75 seconds. The peak yaw rate is the highest yaw rate during
the second part of the maneuver. In the example of Figure 5 (test run
with 279 degrees steering wheel angle) the steering returned to
straight ahead at 2 seconds. At 3 seconds (one second later), the
remaining yaw rate was about 30 percent of the peak value achieved at
about 1.2 seconds. At 3.75 seconds (1.75 seconds after zero steer), the
remaining yaw rate is zero percent. Statistical analyses performed by
NHTSA predict that, if the remaining yaw rate at one second after zero
steer was no more than 35 percent, there is a 95 percent (or greater)
probability that the heading change will not exceed 90 degrees (no
spinout by the empirical criterion). For the 1.75 second time interval,
a remaining yaw rate of no more than 20 percent leads to the same
prediction.
The heading change criterion and its statistical interpretation
provide a context in which to view the yaw rate data in the Sine with
Dwell tests conducted by NHTSA and by the Alliance on a large sample of
62 vehicles in production in 2005. Figure 6 illustrates the yaw rate
response (as a percent of the second yaw rate peak) versus time after
completion of steer (COS) input, for the 0.7 Hz Sine with Dwell
maneuver (left to right steering) for all vehicles tested by NHTSA and
the Alliance. The data represents the most severe yaw rate response
produced for each vehicle during a particular test series. The form of
the graph corresponds to the yaw rate curve (for the 169 degree test)
shown in Figure 4, except that the yaw rate has been normalized and the
time axis has been shifted by 2.0 seconds so as to focus on the yaw
rate response after COS. The cluster of curves at the top of Figure 6
represents the yaw rate response for vehicles with the ESC totally
disabled, and the cluster at the bottom are for vehicles with the ESC
fully enabled. Figure 7 shows data from the same vehicles but in a test
conducted with right-left steering rather than left-right as in Figure
6.
Figures 6 and 7 also show the proposed criteria for maximum yaw
rate at 1.0 second and 1.75 seconds after completion of steering. All
of the 62 current production vehicles tested met or exceeded the
proposed criteria with ESC enabled when tested in the left-right
sequence as shown in Figure 6. However, one of the vehicles did not
meet the criteria when tested in the right-left sequence as shown in
Figure 7. Nevertheless, we believe the proposed criteria reasonably
represent the minimum performance of the oversteer intervention for
present vehicles with ESC, and that the vehicle representing the single
exception to the rule can be tuned to operate as well in the right-left
steering as it did in the left-right test. NHTSA also tested a number
of the older vehicles whose crash data were used to evaluate the
effectiveness of ESC in crash reduction. We believe that over 85
percent of these vehicles have ESC systems that would pass the proposed
criteria. Therefore, the following proposed performance criteria for
the Sine with Dwell Maneuver test of ESC oversteer intervention is
associated with the high level of crash prevention benefits we expect
and is also typical of the minimum performance of the present fleet of
ESC vehicles:
[GRAPHIC] [TIFF OMITTED] TP18SE06.000

In both criteria,
[GRAPHIC] [TIFF OMITTED] TP18SE06.001

C. Responsiveness Criteria

NHTSA's track tests demonstrate dramatic improvements in yaw
stability provided by ESC. However, NHTSA believes these improvements
should not come at the expense of poor lateral displacement response to
the driver's steering inputs. An extreme example of this potential lack
of responsiveness would occur if an ESC system locked both front wheels
as the driver begins an abrupt obstacle avoidance maneuver. Assuming
the road is reasonably level, and the surface friction is uniform, it
is very likely the wheel lock would suppress any tendency for the
vehicle to spin out or tip up. However, having the wheels lock would
also prevent the

[[Page 54727]]

vehicle from responding to the driver's steering inputs. This would
cause the vehicle to plow straight ahead and collide with the obstacle
the driver was trying to avoid. Clearly this is not a desirable
compromise.
To ensure an acceptable balance between lateral stability and the
ability for the vehicle to respond to the driver's inputs, NHTSA
believes a ``responsiveness'' criterion must supplement the agency's
lateral stability criteria. We propose to use the same series of tests
with the Sine with Dwell maneuver to characterize both the
aggressiveness of the oversteer intervention and the lateral
responsiveness of the vehicle. This maneuver is severe enough to
exercise the ESC system on any vehicle and test its oversteer
intervention, and it is possible to measure other metrics during the
Sine with Dwell maneuver to characterize the vehicle's responsiveness
as well.
NHTSA considered a number of metrics to describe the ability of the
vehicle to react to the steering input, especially in the direction of
the first half sine of the steering pattern that would relate most
directly to obstacle avoidance. These metrics involved the lateral
movement of the vehicle, the lateral speed of the vehicle, the lateral
acceleration of the vehicle and lag times and distances between
steering inputs and the various types of responses.
The lateral movement of the vehicle has the most obvious and direct
bearing on obstacle avoidance. However, the measurement of lateral
movement appeared to introduce an undesirable degree of difficulty.
NHTSA has been measuring the path of vehicles during the development of
various rollover and handling test maneuvers using a differentially
corrected Global Positioning System (GPS) method. This method is
capable of measuring the lateral movement of the vehicle at its center
of gravity (a good way to compare vehicles of different sizes), but it
requires costly instruments both on the track and in the vehicle and
complex procedures. Instruments imbedded in the track would seem to be
a possible alternative, but they are also problematic. It is difficult
to place each test vehicle over the instrumented section of roadway
during the exact same position in the Sine with Dwell steering pattern,
and it is difficult to determine the lateral movement of the center of
gravity from roadway sensors when the vehicles approach at various side
slip angles.
However, during a briefing \23\ on September 7, 2005, the Alliance
presented a technique that would greatly simplify the measurement of
NHTSA's preferred responsiveness metric--lateral displacement in the
direction of the first steering of the Sine with Dwell maneuver. It
involves mathematical integration of the onboard lateral acceleration
measurement at the vehicle center of gravity to obtain lateral
velocity, and then a second integration of lateral velocity to obtain
lateral displacement. Double integration of acceleration to calculate
displacement is not used as a general measurement technique because
small errors in zero levels of acceleration and speed can produce large
errors in displacement over time. However, the idea presented by the
Alliance required double integration for only about one second, and the
resulting displacement calculations were in good agreement with the GPS
measurements for vehicles tested by NHTSA.
---------------------------------------------------------------------------

\23\ Docketed at NHTSA-2004-19951, item 21.
---------------------------------------------------------------------------

Figure 8 shows the typical lateral displacement as a function of
time for a vehicle performing the Sine with Dwell maneuver successfully
(without spinning out). Since the longitudinal travel is roughly
proportional to time, the bottom trace resembles the path of the
vehicle with the lateral travel exaggerated. Assuming the wheel is
first turned to the left, the figure shows that the maximum movement of
the vehicle to the left lags the maximum left steering angle by almost
two seconds in this example. Because this maneuver includes a very fast
steering reversal, the steering wheel has been turned sharply to the
right before the vehicle has achieved its maximum reaction to the
initial left steering.
We propose to use the lateral displacement at 1.07 seconds after
initiation of steering in the Sine with Dwell maneuver as the
responsiveness metric rather than the maximum lateral displacement for
the following reasons. The maximum lateral displacement occurs later in
the maneuver and occurs at different times for different vehicles.
Therefore, it is subject to greater potential error from the double
integration technique, and the errors could systematically affect some
types of vehicles more than others.
More importantly, since the interpretation of the metric is the
obstacle avoidance capability of the vehicle, it makes the most sense
to measure the lateral displacement of every vehicle the same distance
from the initiation of steering. This is equivalent to placing the same
size obstruction at the same place on the roadway for every vehicle.
Since steering is initiated at 50 mph for all tests, and not much speed
is scrubbed off in the first second (except for a few systems that
start automatic braking very early in the maneuver), lateral
displacement at a set time is roughly equivalent to lateral
displacement at a set distance. Certainly, the difference in distance
traveled among test vehicles is much less at 1.07 seconds into the
maneuver than at the point of maximum lateral displacement.
A set time of 1.07 seconds is desirable because it coincides with
an easily recognized discontinuity in the steering trace (the dwell
period); it is short enough to assure accuracy of the double
integration technique, and it is long enough to include a high percent
of the maximum lateral displacement. It is also important to note that
differences between vehicles in the lateral displacement metric at 1.07
seconds correlated well with the subjective evaluations of vehicle
responsiveness provided by expert drivers from several vehicle
manufacturers.
The choice of the criterion for this metric was based on the
responsiveness of the present fleet of cars and light trucks,
represented by a group of 61 vehicles in 107 vehicle configurations
(ESC on or ESC off). The group ranged from high-performance sports cars
to a 15-passenger van with ESC and several long wheelbase diesel pickup
trucks with GVWRs near 4,536 Kg (10,000 lb) and no ESC. Figure 9 shows
the range of responsiveness for this fleet, characterized by the
proposed metric. The least responsive vehicles were not the 15-
passenger van or large pickup trucks, but rather SUVs with roll
stability control. The highest criterion that can be used without
prohibiting these implementations of roll stability control is a
minimum lateral displacement of 1.83 m (half a 12-foot lane width),
1.07 seconds after initiation of steering in the Sine with Dwell
maneuver conducted with steering angles of 180 degrees or greater.
Therefore, we are proposing the test criterion for minimum vehicle
responsiveness described above because it is practical for all types of
light vehicles including 15-passenger vans, long wheelbase diesel
pickups and SUVs with roll stability control. All of the test vehicles
would satisfy this criterion, including nine SUVs with a roll stability
control function. However, we expect that manufacturers would make some
software alterations to the roll stability control programs of a few
SUVs to gain a greater margin of compliance.

[[Page 54728]]

D. Other Issues

1. ESC Off Switches
Many vehicles are equipped with ESC systems featuring driver-
selectable modes. These modes are generally subdivided into two groups:
(1) Systems in which the driver has the ability to fully disable the
ESC (i.e., throttle and brake intervention are both eliminated), and
(2) those in which the ESC may only be partially disabled. If the
option to fully disable the ESC exists, the manner in which it is
accomplished depends largely on the vehicle's make and model. For some
vehicles, disabling the ESC is accomplished by momentarily pushing an
on/off button typically located on the instrument panel, center
console, or dashboard. Other vehicles require the driver to push the
ESC on/off button for approximately three to five seconds before the
ESC can be fully disabled.
Regardless of which method the vehicle manufacturer has selected,
the action to manually disable ESC requires a conscious effort by the
driver. The default setting of every ESC system known to NHTSA is
``ESC-enabled.'' In other words, at the beginning of each ignition
cycle, the ESC is always fully enabled regardless of what mode the
driver had been operating the vehicle in during the previous ignition
cycle.
Although many contemporary vehicles are equipped with ESC on/off
switches, simply pushing the ESC on/off button does not necessarily
give the driver the ability to fully disable the vehicle's ESC. For
some vehicles, when the drivers select ``ESC off,'' they are actually
diminishing, but not fully removing, the aggressiveness of their
vehicles' ESC intervention.
Although the crash and test track data clearly demonstrate the
profound safety benefits of ESC, there are special circumstances in
which drivers may wish to partially or fully disable their vehicles'
ESC. Examples of such situations may include:
Attempting to ``rock'' a vehicle stuck in a deformable
surface such as snow or mud
Attempting to initiate movement on deep snow or ice
(especially if the vehicle is equipped with snow chains)
Driving through a deep, deformable surface such as mud or
sand
Driving with a compact spare tire, tires of mismatched
sizes or tires with chains.
To understand how ESC may hinder a driver's ability to operate his
vehicle in these special conditions, it is important to recall the
primary ways in which ESC attempts to improve stability: (1) Removal or
augmentation of drive torque, and (2) brake intervention. In each of
the examples provided above, the vehicle may require significant
longitudinal wheel slip in order to initiate or maintain forward
progress. If ESC remains fully enabled, it will endeavor to reduce what
it perceives as excessive wheel slip via throttle and/or brake
intervention. By reducing wheel slip, the vehicle's lateral stability
is improved; however, this may also inhibit forward progress to the
point that the vehicle may become (or remain) stuck. Not only can this
be frustrating for the driver (i.e., the vehicle is not responding to
their commands), but it may also introduce a potential safety problem
(e.g., the vehicle slows to a near stop while attempting to be driven
through a busy intersection).
Another reason a driver may wish to disable ESC has less to do with
mobility, and more to do with driving enjoyment. NHTSA acknowledges
there is a driver demographic that considers the automobile more than
just a means of transportation. These drivers enjoy participation in
activities such as motorsports competition and high-performance driving
schools. In these situations, it is quite possible the driver may not
wish to realize the improved lateral stability offered by a fully
enabled ESC, because the intervention providing improved lateral
stability is achieved by removing the driver's throttle inputs and
applying the brakes. In a controlled environment, such as the confines
of a racetrack, this can be frustrating for the driver because ESC
intervention will have the effect of slowing the vehicle and contradict
the driver's desire to achieve the lowest possible lap times. In other
words, aggressive intervention intended to improve safety on the public
roads may not be appropriate at a racetrack.
To accommodate these special situations, NHTSA believes vehicle
manufacturers should be allowed the freedom to install ESC on/off
switches on all vehicles. Furthermore, the agency is hopeful that this
provision will have a positive effect on ESC design philosophy. For
every ESC system presently in production, there exists a balance
between lateral stability and intervention magnitude. Generally
speaking, an ESC tuned to optimize lateral stability will require
intrusive interventions. Conversely, a vehicle equipped with an ESC
designed with transparent intervention which is not noticeable to the
driver (often associated with ``sport'' modes), will tend to exhibit
lower lateral stability. By giving vehicle manufacturers the freedom to
install ESC on/off switches, both intervention strategies can be
accommodated, with the more aggressive safety-biased tuning set as the
system default. The more sport-oriented, transparent interventions
could then be accessed via the same switch capable of fully disabling
the ESC. This provision should satisfy the demand for safe, versatile,
and enjoyable vehicles.
Vehicle and ESC manufacturers have expressed concern that if ESC
on/off switches were to be prohibited, there would exist a risk that
some drivers will fully disable their vehicle's ESC by other means,
such as disconnecting or removing sensors required by the ESC. By
opting to disable ESC in this manner, drivers might unknowingly disable
other important safety features such as the vehicle's antilock brakes.
In some cases, the vehicle's electronic brake proportioning may also be
adversely affected, thereby resulting in a significant reduction of the
vehicle's braking capability. Recognizing the diverse operating
conditions their vehicles may encounter, many vehicle manufacturers
presently equip their vehicles with ESC on/off switches.
In light of the above, we are proposing to permit installation of
ESC Off switches as a manufacturer option. However, in order to
preserve the safety benefits presently associated with ESC, NHTSA is
proposing to require a vehicle equipped with an ESC on/off switch to
satisfy three important criteria:
1. The vehicle's ESC must always be fully enabled at the initiation
of each new ignition cycle, regardless of what mode the driver had
previously specified.
2. When evaluated with its ESC fully enabled, the vehicle
performance must be in compliance with the minimum ESC oversteer
intervention and responsiveness test criteria.
3. The vehicle manufacturer must provide a telltale light that
illuminates to indicate when the vehicle has been put into a mode that
completely disables ESC or renders it unable to satisfy the ESC
oversteer intervention test criteria.
In summary, although there is no way to guarantee drivers will not
use ESC on/off switches to disable their vehicle's ESC during normal
driving, potentially negating the significant safety benefits such
systems offer, NHTSA cannot ignore the fact there are certain operating
conditions under which on/off switches are advantageous. Furthermore,
NHTSA anticipates that ESC developers will utilize this design
flexibility facilitated by the use of ESC on/off switches to maximize
the ESC effectiveness in its default, fully enabled mode.

[[Page 54729]]

2. ESC Activation and Malfunction Symbols and Telltale
Most current ESC systems provide an indication to the driver when
the ESC system is actively intervening to stabilize the vehicle and
provide a warning to the driver if ESC is unavailable due to a failure
in the system. When an ESC Off switch is provided, a telltale reminds
the driver when the ESC has been disabled.
We believe that there are safety benefits associated with certain
of these warnings. There is an obvious safety need to warn the driver
in case of an ESC malfunction so that the system can be repaired. The
safety need to remind the driver of a driver-selected ESC Off state is
also obvious because the driver should restore the ESC function as soon
as possible in order to realize the system's safety benefits. However,
the safety need for an ESC activation indicator to alert the driver
during an emergency situation that ESC is intervening is not obvious,
so the agency undertook research on this point as discussed below.
NHTSA conducted a study \24\ using the National Advanced Driving
Simulator (NADS) that included experiments to gain insight into the
various possibilities regarding ESC activation indicators. The NHTSA
study involved 200 participants in four age groups and simulated
driving on wet pavement. It used maneuvers similar to those described
in Section IV of the Papelis study \25\ also using the NADS. The
activation indicator experiments used road departures and eye glances
to the instrument panel as measures of driver performance. The NHTSA
study compared the performance of drivers given either no indication of
ESC activation, a steady-burning icon telltale, a flashing icon
telltale, or an auditory warning. The ESC telltale used in this study
was the ISO J.14 symbol with the text ``Active'' under it.
---------------------------------------------------------------------------

\24\ Mazzae, E. et al. (2005) The effectiveness of ESC and
related Telltales: NADS Wet Pavement Study, DOT HS 809 978.
\25\ Papelis et al. (2004) Study of ESC Assisted Driver
Performance Using a Driving Simulator, Report No. N)4-003-PR,
University of Iowa.
---------------------------------------------------------------------------

Participants presented with only auditory ESC activation
indications experienced significantly more road departures (15) than
participants receiving visual only indications (steady 8, flashing 8)
or no ESC activation indications (7). This finding was most evident for
the older driver group who experienced a statistically significant
increase in road departure events with the auditory ESC indication
compared to the other three conditions. Younger drivers also showed an
increased road departure rate with the auditory ESC indication,
although not at a statistically significant level. These results of the
road departure study are presented in Table 6.

Table 6.--Percent Road Departures by ESC Activation Indication and Age Group--ESC Trials Only
----------------------------------------------------------------------------------------------------------------
All age
groups Novice Younger Middle Older
combined (percent) (percent) (percent) (percent)
(percent)
----------------------------------------------------------------------------------------------------------------
None........................................... 7 8 8 6 6
Steady......................................... 8 10 4 6 10
Flashing....................................... 8 9 6 9 8
Auditory....................................... 15 6 14 10 30
----------------------------------------------------------------------------------------------------------------

Eye glance behavior was examined to determine whether providing
drivers with an indication of ESC activation would cause them to glance
at the instrument panel. Results show that participants presented with
a flashing ESC telltale glanced at the instrument panel significantly
more frequently (14, statistically significant) during the crash-
imminent event than did participants in the other three ESC conditions.
Participants presented with a flashing ESC telltale also glanced at the
instrument panel approximately twice during the crash-imminent event
versus once for participants in the other three ESC conditions.
However, average glance duration was approximately twice as long for
the auditory ESC indication condition than for the other three ESC
conditions (see Table 7), although this difference was not
statistically significant.

Table 7.--Effect of ESC Activation Indication on Eye Glance Behavior--ESC Trials Only
----------------------------------------------------------------------------------------------------------------
Percent Number of glances per Duration of glances(s)
trials with trial -------------------------
any glance --------------------------
to icon M SD M SD
----------------------------------------------------------------------------------------------------------------
None.......................................... 28 1.4 3.9 0.3 0.9
Steady........................................ 27 1.1 2.6 0.2 0.1
Flashing...................................... 41 2.3 4.7 0.3 0.8
Auditory...................................... 27 1 2.6 0.6 1.6
----------------------------------------------------------------------------------------------------------------

Overall, the significant finding was that the drivers who received
various ESC activation indicators did not perform better than drivers
given no indicator. Therefore, there does not appear to be a safety
need to propose a requirement for an ESC activation indicator as part
of this rulemaking, and none is proposed. In fact, presentation of an
auditory indication of ESC activation was shown to increase the
likelihood of road departure, particularly for older drivers. As a
result, use of an auditory indication of ESC activation presented
during the ESC activation is not recommended.
The flashing indicator was associated with a greater number of
glances to the instrument panel during the critical driving maneuvers.
Therefore, flashing would not seem to be a desirable feature, but there
was no measurable consequence in road departures. The current practice
for many vehicles is to

[[Page 54730]]

use the same ESC telltale for both activation and malfunction. It
flashes to indicate activation and stays on continuously in a steady
burning mode to indicate ESC malfunction. Since NHTSA is proposing to
not regulate the activation mode, the current practice need not be
affected.
The threshold of ESC intervention that would trigger an indication
of activation is likely to vary with the philosophy of the
manufacturer. Some manufacturers would also favor displaying the
activation signal to the driver shortly after the critical driving
maneuver has ended. This idea may be more intuitively appealing because
the driver would be warned of slippery road conditions while avoiding
potential distraction during the critical maneuver. This rulemaking
does not propose regulation in this area.
NHTSA believes that the symbol used to identify ESC malfunction
(and activation if the telltale is shared) should be standardized. This
is not the case for presently available systems. There are three main
types of identifiers for ESC activation and malfunction. One type of
icon shows the rear of a vehicle trailed by a pair of ``S'' shaped skid
marks. This is the ISO ESC symbol (designated J.14 in ISO standard
2575). We observed seven variations of this icon in production
vehicles. The second type is based on a triangle surrounding an
exclamation mark, which is also used to indicate ABS and traction
control activation on some vehicles. A variation of this type adds an
outer counterclockwise semicircular arrow to indicate rotation. The
third type includes English language phrases and acronyms often
referring to trade names for specific ESC systems.
To the extent possible, NHTSA favors symbols over English
abbreviations to promote harmonization. Also, acronyms for different
trade names for ESC would only serve to confuse drivers who operate
different vehicles produced by different manufacturers.
NHTSA collected data on the recognition of various identifiers
related to ESC and other vehicle systems by administration of an icon
comprehension test. A total of 20 members of the general public
participated in this data collection effort. Gender was balanced. Each
participant was first presented with an instructional sheet describing
the procedure for the icon test. The instructions included the
following statement: ``You are driving down the road and this image
illuminates on your vehicle's instrument panel * * * ''. Participants
were then given the test, which consisted of a hand-sized packet
containing the 20 icons, each on a different page. Each page contained
two separate questions to ensure that responses were sufficiently
detailed. The questions were: ``What system or part of the car is the
light referring to?'' and ``What is the light telling you about that
part or system?'' A fill-in-the-blank line for participant response
followed each question.
Responses for ESC-related symbols were given full credit as correct
if they contained the words ``stability control'' or ``ESC.'' ESC icon
responses containing the word ``traction'' were given partial credit.
Selected results of the comprehension test are presented in Figure 10.
While few people knew what ``ESC'' meant, the ISO J.14 icon was the
most successful in communicating to people a message relating to
traction. The icon consisting of a counterclockwise, circular arrow
surrounding a triangle containing an exclamation point, while present
in a number of current vehicles, was not meaningful to any of the 20
respondents, and there was little recognition of the triangle without
the arrow.
Based upon the results of this albeit limited study, the ISO J.14
symbol appears to be the best choice of the identifiers in use for a
standard symbol for ESC. As with any symbol, drivers will have to learn
its precise meaning, but we believe that, to some extent, it correctly
evokes an association with skidding. Also, the ISO J.14 symbol and
close variations were the symbols used presently by the greatest number
of vehicle manufacturers that used an ESC symbol. Therefore, NHTSA is
proposing the ISO J.14 symbol as the required ESC symbol in FMVSS No.
126.
3. ESC Off Switch Symbol and Telltale
There is an obvious safety need to prevent drivers from
misunderstanding the operation of the ESC Off switch. Drivers usually
encounter vehicle dashboard switches as a means of turning on vehicle
functions that are off when the vehicle is started. However, an ESC Off
switch presents the opposite situation, because full ESC operation is
the default condition of the vehicle following each ignition cycle.
Therefore, we believe that the switch must be labeled unambiguously.
The ISO convention is to draw a slash through a symbol to signify
negation--the disabling or turning off of a vehicle function. However,
Table 8, which examines potential symbols to indicate when the ESC
system is off, shows that this convention applied to the ISO J.14 ESC
symbol does not create an unambiguous symbol for ESC off.
[GRAPHIC] [TIFF OMITTED] TP18SE06.002

Once again, the ISO J.14 symbol is desirable because it connoted
the idea of traction and skidding even to people who had not heard of
electronic stability control. However, the literal meaning of the
symbol of a vehicle skidding with a slash through it is the negation of
skidding, which could be assumed to mean ESC on. The problem with the
slash symbol is not just that a driver will not understand it and have
to consult the owner's manual, but that the driver could reasonably
understand it to have the opposite meaning and believe it is not
necessary to consult the owner's manual. Therefore, a purely
pictographic approach to adapting the ESC symbol for the off switch is
not feasible. NHTSA believes it is necessary to make the identification
of when ESC is turned off explicit by using the English word ``OFF,''
as shown in the right hand box of Table 8.
The same situation occurs for the telltale indicating what the
current state of ESC system is. The off switch toggles the ESC system
between the on and off states. Even someone who understands that the
ESC Off switch is not required to use ESC normally must be certain of
the ESC state after he has touched the switch. Therefore, the slash
symbol cannot be used for the telltale either because it leads to the
same ambiguity regarding the state of the ESC system

[[Page 54731]]

when the telltale is lighted. Also, even though it is used for
malfunction indication, the ISO J.14 symbol alone would create
ambiguity about the on/off state of ESC if it were used with the Off
switch. Therefore, the symbol with the English word ``OFF'' is also
proposed for the telltale that will be required for the ESC Off switch.

E. Alternatives to the Agency Proposal

Section 10301 of the Safe, Accountable, Flexible, Efficient
Transportation Equity Act: A Legacy for Users of 2005 \26\ (SAFETEA-LU)
requires that the Secretary ``establish performance criteria to reduce
the occurrence of rollovers consistent with stability enhancing
technologies'' and ``issue a proposed rule * * * by October 1, 2006,
and a final rule by April 1, 2009.'' NHTSA has long been concerned
about the number of rollover fatalities and injuries, and it has
pursued a number of actions in the past to reduce rollovers that were
alternatives to the present proposal.
---------------------------------------------------------------------------

\26\ Pub. L. 109-59, 119 stat. 1144 (2005).
---------------------------------------------------------------------------

One of the past alternatives sought to require higher rollover
resistance for light trucks. NHTSA published an Advance Notice of
Proposed Rulemaking in 1992 \27\ which explored the idea of setting a
minimum level of rollover resistance based on the track width and
height of the center of gravity. These are the primary components of
``geometric stability'' which can be expressed by metrics such as
Static Stability Factor (SSF) or Tilt Table Ratio which is a related
measurement using a ``tilt table'' to measure how far a vehicle on a
platform could be tilted laterally before tipping over.
---------------------------------------------------------------------------

\27\ 57 FR 242 (Jan. 3, 1992).
---------------------------------------------------------------------------

However, the contemplated approach of regulating the geometric
stability of vehicles did not lead to a mandatory standard. Its effect
would have been crash mitigation by reducing the number of single-
vehicle crashes that turn into rollovers rather than crash prevention.
In order to produce life saving benefits, the proposed geometric
stability level would have had to be placed above that of almost all
contemporary SUVs, pickup trucks with four-wheel drive, and full size
vans. A regulation of this type would have made classes of vehicles
with high ground clearance unavailable to consumers.
Rather than pursue such a rulemaking, NHTSA chose instead to add
rollover resistance to the NCAP consumer information program in 2001.
In this way, persons needing vehicles with high ground clearance (which
have poorer rollover resistance) could make an informed choice about
the tradeoffs, but consumers would be encouraged to choose vehicles
with greater rollover resistance. The NCAP program uses market-based
incentives to encourage manufacturers to maximize rollover resistance
within the limitations of the vehicle class. Manufacturers responded to
these NCAP ratings with improvements in rollover resistance resulting
from the generally wider track widths of newer SUVs derived from
passenger car platforms and also improvements where possible in truck-
based SUVs during major redesigns. A recent trend in improving the
rollover resistance of SUVs has been the addition of roll stability
control. This feature prevents tip-up in the maneuver test that was
added to NCAP in the 2004 model year, resulting in a small reduction in
the predicted rollover rate.
We believe the NCAP approach has been a successful way to address
the dilemma of higher rollover resistance being at odds with some of
the features that draw consumers to light trucks. Despite the recent
trend of improvement, SUVs cannot match passenger cars in geometric
stability because taller bodies and higher ground clearance are the
features that distinguish SUVs from passenger cars. Nevertheless, the
rollover resistance of SUVs has substantially improved since the
establishment of NCAP ratings, and consumers are in a better position
to make vehicle decisions for themselves and for young drivers in their
family.
While the use of ESC to prevent single vehicle crashes is a better
way of reducing rollovers than any countermeasures previously
available, there are alternatives in terms of how NHTSA could regulate
ESC systems. The agency considered two alternatives to the proposal.
The first was to limit the ESC standard's applicability only to LTVs.
The second alternative was to not require a 4-wheel system, which would
allow a 2-wheel system to be used by manufacturers.
The agency considered the first alternative for two reasons: (a)
The ESC effectiveness rates for LTVs against single-vehicle crashes
were almost twice as high of the effectiveness rates for passenger cars
(PCs), and (b) LTVs generally had a higher propensity for rollover than
PCs. The alternative would address the core rollover issue and target
the high-risk rollover vehicle population. However, after examining the
safety impact and the cost-effectiveness of the alternative, the agency
determined that an excellent opportunity to reduce passenger car
crashes would be lost if PCs were excluded from the proposal.
We examined this alternative by looking at the impacts of requiring
ESC for passenger cars. Requiring ESC for passenger cars would save 956
lives and reduce 34,902 non-fatal injuries. Following this analysis
through the cost-effectiveness equations, the cost-effectiveness
analysis shows that ESC is highly cost-effective for PCs alone. For
PCs, the cost per equivalent life saved is estimated to be $0.35
million at a 3 percent discount rate and $0.47 million at a 7 percent
discount rate. The benefit-cost would be $4.8 billion at a 3 percent
discount rate and $3.8 billion at a 7 percent discount rate.
Given the fact that ESC is highly cost-effective and that extending
the ESC applicability to PCs would save a large number of additional
lives (956) and reduce a large number of additional injuries (34,902),
the agency is not proposing this alternative.
The second alternative considered was to require only that ESC
operate on the two front wheels. General Motors has utilized a 2-wheel
ESC system in many of its ESC-equipped passenger cars through MY 2005,
but it is using 4-wheel ESC systems exclusively in MY 2006. All other
manufacturers have utilized a 4-wheel ESC system in their vehicles.
Only 4-wheel systems are capable of both understeer and oversteer
mitigation.
Statistical analyses comparing 2-wheel to 4-wheel ESC systems were
performed.\28\ The effectiveness estimates show a potentially enhanced
benefit of 4-wheel ESC systems over 2-wheel ESC systems in reducing
single-vehicle run-off-road crashes (significant at the 0.05 level or
better), although the benefit could not have been shown in a separate
analysis of fatal-only crashes likely due to the small sample size.
---------------------------------------------------------------------------

\28\ Dang, J. (2006) Statistical Analysis of The Effectiveness
of Electronic Stability Control (ESC) Systems, U.S. Dept. of
Transportation, Washington, DC (publication pending peer review). A
draft version of this report, as supplied to peer reviewers, has
been placed in the docket for this rulemaking.
---------------------------------------------------------------------------

The agency's contractor performed a teardown study to determine the
difference in costs between a 2-wheel and 4-wheel system, and it found
that the 2-wheel system is about $10.00 less expensive. However, it is
not intuitively obvious that the difference need be this much, and with
a sample size of one, it is possible that other changes in design may
be affecting this estimate.
Since the industry has moved away from the 2-wheel system on its
own, and it appears that the difference in cost of $10 or less will be
insignificant compared to the additional benefits

[[Page 54732]]

achieved with 4-wheel ESC, we are not providing a full analysis of this
alternative at this time.
Based on the available information, the agency is proposing the 4-
wheel system. The agency's decision is based on our and the industry's
engineering judgment that the 4-wheel system is more effective, the
effectiveness study showing that the 4-wheel system is more effective
than the 2-wheel system in reducing crashes, the industry trend towards
installing the 4-wheel system in their vehicles, and the minimal cost
differences between 2-wheel and 4-wheel ESC systems.
We have also examined the possibility that there may be alternative
approaches to achieving the benefits of ESC that could involve simpler
or less costly technology. To answer this question we first identified
the basic functional requirements of a vehicle control system that
would maintain vehicle path control in both oversteer and understeer
situations. The first functional requirement is a means of predicting
what the driver's intended path, i.e., where the driver wants the
vehicle to go. The second functional requirement is to be able to
determine the current actual path of the vehicle, i.e., its current
dynamic state. The final requirement is to determine how the intended
and actual paths deviate and then to exercise automatic control to
minimize or eliminate this deviation. The basic question then is
whether there exists another fundamentally different technological
approach to achieving the three key functional requirements identified
above, than those employed in current ESC systems.
Functional Requirement No. 1: One may infer the desired path from a
knowledge of the driver's instantaneous steering, throttle, and braking
commands as well as the current dynamic state of the vehicle. This
requires that sensors be installed to determine the values of each of
these control inputs. Although specific sensor technology and costs may
vary from one manufacturer to another, there is no known alternative to
acquiring knowledge of the driver's intent other than through this
system of vehicle sensors.
Functional Requirement No. 2: Once the intended path is
established, the next requirement is determine the vehicle's actual
path. Here again a range of sensor information is needed to establish
the vehicle's dynamic state. Among the state variables that must be
determined, the two most critical are lateral acceleration and yaw
velocity. Acquiring information of these quantities requires special
vehicle dynamic sensors. Again, though sensor technology and cost may
vary, we are not aware of any alternative approach to acquiring this
essential information.
Functional Requirement No. 3: With information on the driver's
desired path and the actual vehicle path, a means of comparing the two
and eliminating or minimizing deviations is needed. This requires an
electronic comparator and error generator. A means of altering the
actual vehicle path so as to bring it into alignment with the desired
path is the third critical function. The vehicle path can only be
changed as a result of forces generated between the tire and roadway.
Drivers intuitively rely on lateral tire forces generated through
steering inputs to change the vehicle heading and path. Though not
comprehended by most drivers, the heading (and consequently the path)
can also be changed by means of unbalanced braking forces, which is the
approach used by ESC. We do not believe that an approach that would
assume control of the driver's steering authority as an alternative
method of correcting the vehicle path would be acceptable to most
drivers. Also, braking intervention at individual wheels is much more
likely to produce the necessary yaw torque on slippery surfaces than
steering intervention, and steering intervention would have limited
effect on understeer loss-of-control even on surfaces with high levels
of friction. No manufacturer has proposed this method of intervention
to correct path deviation in loss of control situations.
In summary, while specific differences in the implementation may
exist between ESC systems, the basic elements of the feed-back control
systems are common to all. We have concluded that to accomplish the
goal of preventing a vehicle from losing path or directional control a
vehicle must be equipped with all of the essential components of the
current ESC systems. There does not appear to be any current
alternative to the technology that is being mandated that attains the
goals of this proposed rule. We solicit comment on alternatives to
mandating the installation of ESC, consistent with our statutory
directive.

VI. Leadtime

Considering the very high level of potential life-saving benefits
of this proposed safety standard, NHTSA wishes to avoid excessive delay
in its development and implementation. Except for possibly some low-
production-volume vehicles with infrequent design changes, NHTSA
believes that most other vehicles can reasonably be equipped with ESC
within three to four model years (MY) from the date of issuance of a
final rule. This proposal does not require improvements in ESC
technology over the present 2006 MY systems, and most vehicles would
likely experience some level of redesign in the next five years in the
normal course of business. There already is a strong trend to provide
ESC as standard equipment on SUVs, and it is likely that market segment
will be equipped with ESC prior to a final rule becoming effective. We
have taken these considerations into account in proposing both the
phase-in plan as well as the final compliance date for full
implementation of the standard.
Our intention is to have 90 percent of the subject fleet equipped
with ESC in the 2011 model year that starts September 1, 2010.
Accordingly, assuming the final rule is published in June 2008, and
becomes effective September 1, 2008, we are proposing the following
phase-in schedule:

September 1, 2008--30 percent of fleet.
September 1, 2009--60 percent of fleet.
September 1, 2010--90 percent of fleet.
September 1, 2011--All light vehicles.

However, NHTSA is proposing to exclude multi-stage manufacturers
and alterers from the requirements of the phase-in and to extend by one
year the time for compliance by those manufacturers (i.e., until
September 1, 2012). This NPRM also proposes to exclude small volume
manufacturers (i.e., manufacturers producing less than 5,000 vehicles
for sale in the U.S. market in one year) from the phase-in, instead
requiring such manufacturers to fully comply with the standard on
September 1, 2011.
Under our proposal, vehicle manufacturers would be permitted to
earn carry-forward credits for compliant vehicles, produced in excess
of the phase-in requirements, which are manufactured between the
effective date of the final rule and the conclusion of the phase-in
period. We note that carry-forward credits would not be permitted to be
used to defer the mandatory compliance date of September 1, 2011 for
all covered vehicles.
The initial phase-in of 30 percent occurring almost simultaneously
with the effective date is the result of our belief that all
manufacturers subject to the phase-in already plan to exceed that level
of ESC installation in the 2009 MY. Confidential information submitted
to NHTSA by many manufacturers indicate that all responding
manufacturers will exceed a 30 percent installation rate, and that
several will exceed it by a large margin that would earn considerable
carry-forward credits.

[[Page 54733]]

VII. Benefits and Costs

A. Summary

This section summarizes our analysis of the benefits, costs, and
cost per equivalent life saved as a result of the proposed ESC
requirement. As noted previously, the life- and injury-saving potential
of ESC is very significant, both in absolute terms and when compared to
prior agency rulemakings. This proposal for ESC, if made final, would
save 1,536 to 2,211 lives and cause a reduction of 50,594 to 69,630
MAIS 1-5 injuries annually once all passenger vehicles have ESC. This
compares favorably with the Regulatory Impact Analyses for other
important rulemakings such as FMVSS No. 208 mandatory air bags (1,964
to 3,670 lives saved), FMVSS No. 214 side impact protection (690 to
1,030 lives saved), and FMVSS No. 201 upper interior head impact
protection (870 to 1,050 lives saved). The ESC proposal would also save
$396 to $555 million annually in property damage and travel delay
(undiscounted). The total cost of the proposal is estimated to be $985
million.
The proposal is extremely cost-effective. The cost per equivalent
life saved would range from $0.19 to $0.32 million at a 3 percent
discount and $0.27 to $0.43 million at a 7 percent discount. Again, the
cost-effectiveness for ESC compares favorably with the Regulatory
Impact Analyses for other important rulemakings such as FMVSS No. 202
head restraints safety improvement ($2.61 million per life saved),
FMVSS No. 208 center seat shoulder belts ($3.39 to $5.92 million per
life saved), FMVSS No. 208 advanced air bags ($1.9 to $9.0 million per
life saved), and FMVSS No. 301 fuel system integrity upgrade ($1.96 to
$5.13 million per life saved).
For a more complete discussion of the benefits and costs associated
with this proposed rulemaking for ESC, please consult the Preliminary
Regulatory Impact Analysis (PRIA), which is available in the docket for
this rulemaking.

B. ESC Benefits

As discussed in detail in Chapter IV (Benefits) of the PRIA, we
anticipate that this rulemaking would prevent 70,344 to 95,153 crashes
(1,408 to 2,355 fatal crashes and 69,936 to 91,798 non-fatal crashes).
Preventing these crashes entirely is the ideal safety outcome and would
translate into 1,536 to 2,211 lives saved and 50,594 to 69,630 MAIS 1-5
injuries prevented.
The above figures include benefits related to rollover crashes.
However, in light of the relatively severe nature of crashes involving
rollover, ESC's contribution toward mitigating the problem associated
with this subset of crashes should be noted. We anticipate that this
rulemaking would prevent 37,309 to 41,147 rollover crashes (1,057 to
1,314 fatal crashes and 36,252 to 39,833 non-fatal crashes). This would
translate into 1,161 to 1,445 lives saved and 43,901 to 49,010 MAIS 1-5
injuries prevented in rollovers.
In addition, preventing crashes would also result in benefits in
terms of travel delay savings and property damage savings. We estimate
that this rulemaking would save $396 to $555 million, undiscounted, in
these two categories ($310 to $348 million of this savings attributable
to prevented rollover crashes).

C. ESC Costs

In order to estimate the cost of the additional components required
to equip every vehicle in future model years with an ESC system,
assumptions were made about future production volume and the
relationship between equipment found in anti-lock brake systems (ABS),
traction control (TC), and ESC systems. We assumed that in an ESC
system, the equipment of ABS is a prerequisite. Thus, if a passenger
car did not have ABS, it would require the cost of an ABS system plus
the additional incremental costs of the ESC system to comply with an
ESC standard. We assumed that traction control (TC) was not required to
achieve the safety benefits found with ESC. We estimated a future
annual production of 17 million light vehicles consisting of nine
million light trucks and eight million passenger cars.
An estimate was made of the MY 2011 installation rates of ABS and
ESC. It served as the baseline against which both costs and benefits
are measured. Thus, the cost of the standard is the incremental cost of
going from the estimated MY 2011 installations to 100 percent
installation of ABS and ESC. The estimated MY 2011 installation rates
are presented in Table 9.

Table 9.--MY 2011 Predicted Installations
[Percent of the light vehicle fleet]
------------------------------------------------------------------------
ABS ABS + ESC
------------------------------------------------------------------------
Passenger Cars................................ 86 65
Light Trucks.................................. 99 77
------------------------------------------------------------------------

Based on the assumptions above and the data provided in Table 9,
Table 10 presents the percent of the MY 2011 fleet that would need
these specific technologies in order to equip 100 percent of the fleet
with ESC.

Table 10.--Percent of the Light Vehicle Fleet Requiring Technology To
Achieve 100% ESC Installation
------------------------------------------------------------------------
None ABS + ESC ESC only
------------------------------------------------------------------------
Passenger Cars................... 65 14 21
Light Trucks..................... 77 1 22
------------------------------------------------------------------------

The cost estimates developed for this analysis were taken from tear
down studies that contractors have performed for NHTSA. This process
resulted in estimates of the consumer cost of ABS at $368 and the
incremental cost of ESC at $111. Thus, it would cost a vehicle that
does not have ABS currently, $479 to meet this proposal. Combining the
technology needs in Table 10 with the cost above and assumed production
volumes yields the cost estimate in Table 11 for the proposed standard.

[[Page 54734]]

Table 11.--Summary of Vehicle Costs for the ESC Proposal
[2005$]
------------------------------------------------------------------------
Average Total costs
vehicle costs (million)
------------------------------------------------------------------------
Passenger Cars............................. $90.3 $728
Light Trucks............................... 29.2 363
----------------------------
Total.................................. 58 985
------------------------------------------------------------------------

In summary, Table 11 shows that the new vehicle costs of providing
electronic stability control and antilock brakes will add approximately
$985 million to new light vehicles at a cost averaging over $58 per
vehicle.
In addition, we note that this proposal would add weight to
vehicles and consequently would increase their lifetime use of fuel.
Most of the added weight is for ABS components and very little is for
the ESC components. Since 99 percent of light trucks are predicted to
have ABS in MY 2011, the weight increase for light trucks is less than
one pound and is considered negligible. The average weight gain for
passenger cars is estimated to be 2.1 pounds, resulting in 2.6 more
gallons of fuel being used over the lifetime of these vehicles. The
present discounted value of the added fuel cost over the lifetime of
the average passenger car is estimated to be $2.73 at a 7 percent
discount rate and $3.35 at a 3 percent discount rate.
We have not included in these cost estimates, allowances for ESC
system maintenance and repair. Although all complex electronic systems
will experience component failures from time to time necessitating
repair, our experience to date with existing systems is that their
failure rate is not outside the norm. Also, there are no routine
maintenance requirements for ESC systems.

VIII. Public Participation

How Can I Influence NHTSA's Thinking on This Notice?

In developing this notice, NHTSA tried to address the concerns of
all stakeholders. Your comments will help us determine what standard
should be set for ESC as part of FMVSS No. 126. We invite you to
provide different views about the issues presented, new approaches and
technologies about which we did not ask, new data, how this notice may
affect you, or other relevant information. We welcome your views on all
aspects of this notice. Your comments will be most effective if you
follow the suggestions below:
Explain your views and reasoning as clearly as possible.
Provide empirical evidence, wherever possible, to support
your views.
If you estimate potential costs, explain how you arrived
at that estimate.
Provide specific examples to illustrate your concerns.
Offer specific alternatives.
Reference specific sections of the notice in your
comments, such as the units or page numbers of the preamble, or the
regulatory sections.
Be sure to include the name, date, and docket number of
the proceeding as part of your comments.

How Do I Prepare and Submit Comments?

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

How Can I Be Sure That My Comments Were Received?

If you wish Docket Management to notify you upon its receipt of
your comments, enclose a self-addressed, stamped postcard in the
envelope containing your comments. Upon receiving your comments, Docket
Management will return the postcard by mail. Each electronic filer will
receive electronic confirmation that his or her submission has been
received.

How Do I Submit Confidential Business Information?

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

Will the Agency Consider Late Comments?

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

How Can I Read the Comments Submitted by Other People?

You may read the comments received by Docket Management at the
address given above under ADDRESSES. The hours of the Docket are
indicated above in the same location.
You may also review filed public comments on the Internet. To read
the comments on the Internet, take the following steps:
1. Go to the Docket Management System (DMS) Web page of the
Department of Transportation (http://dms.dot.gov/).
2. On that page, click on ``search.''

[[Page 54735]]

3. On the next page (http://dms.dot.gov/search/), type in the four-
digit docket number shown at the beginning of this document. (Example:
If the docket number were ``NHTSA-1998-1234,'' you would type
``1234.'') After typing the docket number, click on ``search.''
4. On the next page, which contains docket summary information for
the docket you selected, click on the desired comments. You may
download the comments. Although the comments are imaged documents,
instead of word processing documents, the ``pdf'' versions of the
documents are word searchable.
Please note that even after the comment closing date, we will
continue to file relevant information in the Docket as it becomes
available. Further, some people may submit late comments. Accordingly,
we recommend that you periodically check the Docket for new material.

Data Quality Act Statement

Pursuant to the Data Quality Act, in order for substantive data
submitted by third parties to be relied upon and used by the agency, it
must also meet the information quality standards set forth in the DOT
Data Quality Act guidelines. Accordingly, members of the public should
consult the guidelines in preparing information submissions to the
agency. DOT's guidelines may be accessed at http://dmses.dot.gov/submit/DataQualityGuidelines.pdf.

IX. Regulatory Analyses and Notices

A. Vehicle Safety Act

Under 49 U.S.C. Chapter 301, Motor Vehicle Safety (49 U.S.C. 30101
et seq.), the Secretary of Transportation is responsible for
prescribing motor vehicle safety standards that are practicable, meet
the need for motor vehicle safety, and are stated in objective
terms.\29\ These motor vehicle safety standards set the minimum level
of performance for a motor vehicle or motor vehicle equipment to be
considered safe.\30\ When prescribing such standards, the Secretary
must consider all relevant, available motor vehicle safety
information.\31\ The Secretary also must consider whether a proposed
standard is reasonable, practicable, and appropriate for the type of
motor vehicle or motor vehicle equipment for which it is prescribed and
the extent to which the standard will further the statutory purpose of
reducing traffic accidents and associated deaths.\32\ The
responsibility for promulgation of Federal motor vehicle safety
standards has been delegated to NHTSA.\33\
---------------------------------------------------------------------------

\29\ 49 U.S.C. 30111(a).
\30\ 49 U.S.C. 30102(a)(9).
\31\ 49 U.S.C. 30111(b).
\32\ Id.
\33\ 49 U.S.C. 105 and 322; delegation of authority at 49 CFR
1.50.
---------------------------------------------------------------------------

As noted previously, section 10301 of SAFETEA-LU mandated a
regulation to reduce the occurrence of rollovers ``consistent with
stability enhancing technologies.'' In developing this proposed rule
for ESC, the agency carefully considered the statutory requirements of
both SAFETEA-LU and 49 U.S.C. Chapter 301.
First, in preparing this document, the agency carefully evaluated
available research, testing results, and other information related to
ESC technology. The agency performed extensive research on its own and
made use of research performed by the Alliance of Automobile
Manufacturers. We have also performed analyses of ESC using actual
crash data to determine the effectiveness of ESC in reducing single-
vehicle crashes and rollovers. In sum, this document reflects our
consideration of all relevant, available motor vehicle safety
information.
Second, to ensure that the ESC requirements are practicable, the
agency research and the Alliance research documented the capabilities
of current ESC systems and dynamic performance of model year 2005
vehicles equipped with them. We have tentatively concluded that all
current production vehicles equipped with ESC systems would comply with
the equipment requirements, that all but one vehicle would comply with
the performance tests proposed, and that only minor software tuning
would be required to bring that vehicle into compliance. In sum, we
believe that this proposed rule is practicable, in that it could be
implemented with existing technology and is quite cost effective given
its potential to prevent thousands of deaths and injuries each year,
particularly those associated with single-vehicle crashes leading to
rollover.
Third, the regulatory text following this preamble is stated in
objective terms in order to specify precisely what equipment
constitutes an ESC system, what performance is required and how
performance would be tested under the standard. The proposed definition
of an ESC system is based on an industry consensus definition developed
by the Society of Automotive Engineers (SAE). The proposed rule also
includes performance requirements and test procedures for the timing
and intensity of the oversteer intervention of the ESC system and the
responsiveness of the vehicle. This test procedure involves a precisely
defined steering pattern performed by a robotic steering machine under
a defined set of test conditions (e.g., ambient temperature, road test
surface, vehicle load, vehicle speed). Performance is defined by
objective measurements of yaw rate and lateral acceleration taken by
scientific instruments at precise times with reference to the steering
pattern. The standard's test procedures carefully delineate how testing
would be conducted. Thus, the agency believes that this test procedure
is sufficiently objective and would not result in any uncertainty as to
whether a given vehicle satisfies the requirements of the ESC standard.
Finally, we believe that this proposed rule is reasonable and
appropriate for motor vehicles subject to the applicable requirements.
As discussed elsewhere in this notice, the agency is addressing
Congress' concern about rollover crashes resulting in fatalities and
serious injuries. Under section 10301 of SAFETEA-LU, Congress mandated
installation of stability enhancing technologies in new vehicles to
reduce rollovers. NHTSA has determined that ESC systems meeting the
requirements of this proposed rule offer an effective countermeasure to
rollover crashes and to other single-vehicle and certain multi-vehicle
crashes. Accordingly, we believe that this proposed rule is appropriate
for vehicles that would become subject to these provisions because it
furthers the agency's objective of preventing deaths and serious
injuries, particularly those associated with rollover crashes.

B. Executive Order 12866 and DOT Regulatory Policies and Procedures

Executive Order 12866, ``Regulatory Planning and Review'' (58 FR
51735, October 4, 1993), provides for making determinations whether a
regulatory action is ``significant'' and therefore subject to Office of
Management and Budget (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;

[[Page 54736]]

(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.
We have considered the impact of this action under Executive Order
12866 and the Department of Transportation's regulatory policies and
procedures. This action has been determined to be economically
significant under the Executive Order, and it is also a subject of
congressional interest and a mandate under section 10301 of SAFETEA-LU.
The agency has prepared and placed in the docket a Preliminary
Regulatory Impact Analysis. This rulemaking action is also significant
within the meaning of the Department of Transportation's Regulatory
Policies and Procedures (44 FR 11034; February 26, 1979). Accordingly,
this rulemaking document was reviewed by the Office of Management and
Budget under Executive Order 12866, ``Regulatory Planning and Review.''
The agency has estimated that compliance with this proposal would cost
approximately $985 million per year and have net benefits as high as
$10.6 billion per year. Thus, this rule would have greater than a $100
million effect.

C. Regulatory Flexibility Act

Pursuant to the Regulatory Flexibility Act of 1980 (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).
However, no regulatory or flexibility analysis is required if the head
of an agency certifies that 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 rulemaking action under
the Regulatory Flexibility Act and has included an initial regulatory
flexibility analysis in the PRE. This analysis discusses potential
regulatory alternatives that the agency considered that would still
meet the identified safety need of reducing the occurrence of rollovers
through stability enhancing technologies. Alternatives considered
included (a) applying the standard to light trucks but not to passenger
cars and (b) permitting front-wheel-only ESC systems that are incapable
of understeer intervention. The first alternative was rejected because
passenger car ESC systems would save 956 lives and reduce 34,902
injuries annually at a cost per equivalent fatality that would easily
justify a separate rule for passenger cars. The second alternative was
rejected because front-wheel-only ESC systems would prevent 30 percent
fewer single-vehicle crashes without producing a large cost saving.
To summarize the conclusions of that analysis, the agency believes
that the proposal would have a significant economic impact on a
substantial number of small businesses. There are currently four small
domestic motor vehicle manufacturers in the United States, each having
fewer than 1,000 employees. Although the cost for an ESC system is
relatively high, we believe that these manufacturers would be able to
pass the associated costs on to purchasers without decreasing sales
volume, because the demand for these high-end, luxury vehicles tends to
be inelastic and the increase in total vehicle cost is expected to be
only 0.2-1.1 percent.
There are a significant number of final-stage manufacturers and
alterers that could be impacted by the proposed rule for ESC, some of
which buy incomplete vehicles. However, final-stage manufacturers and
alterers typically do not modify the brake system of the vehicle, so
the original manufacturer's certification of the ESC system should pass
through for these vehicles. We believe that increased costs associated
with ESC would impact all such final-stage manufacturers and alterers
equally, and that such costs would be passed on to consumers.
Furthermore, we have no reason to believe that an average cost of $90
per passenger car and $29 per truck will cause a significant decline in
overall vehicle sales.
We do not expect manufacturers of ESC systems to be classified as
small businesses.

D. Executive Order 13132 (Federalism)

Executive Order 13132 sets forth principles of federalism and the
related policies of the Federal government. NHTSA has analyzed this
rule in accordance with the principles and criteria set forth in
Executive Order 13132, Federalism, and has determined that it does not
have sufficient Federal implications to warrant consultation with State
and local officials or the preparation of a Federalism summary impact
statement. The rule will not have any substantial impact on the States,
or on the current Federal-State relationship, or on the current
distribution of power and responsibilities among the various local
officials. However, 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.

E. Executive Order 12988 (Civil Justice Reform)

Pursuant to Executive Order 12988, ``Civil Justice Reform'' (61 FR
4729, February 7, 1996), the agency has considered whether this
proposed rule would have any retroactive effect. This proposed rule
would 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 of a motor vehicle or motor vehicle equipment 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. Executive Order 13045 (Protection of Children From Environmental
Health and Safety Risks)

Executive Order 13045, ``Protection of Children from Environmental
Health and Safety Risks'' (62 FR 19855, April 23, 1997), applies to any
rule that: (1) Is determined to be ``economically significant'' as
defined under Executive Order 12866, and (2) concerns an environmental,
health, or safety risk that the agency has reason to believe may have a
disproportionate effect on children. If the regulatory action meets
both criteria, the agency must evaluate the environmental health or
safety effects of the planned rule on children, and explain why the
planned regulation

[[Page 54737]]

is preferable to other potentially effective and reasonably feasible
alternatives considered by the agency.
Although the proposed rule for ESC has been determined to be an
economically significant regulatory action under Executive Order 12866,
the problems associated with loss of vehicle control equally impact all
persons riding in a vehicle, regardless of age. Consequently, the
proposed rule does not involve a decision based on environmental,
health, or safety risks that disproportionately affect children and
would not necessitate further analyses under Executive Order 13045.

G. Paperwork Reduction Act

Under the Paperwork Reduction Act of 1995 (PRA), a person is not
required to respond to a collection of information by a Federal agency
unless the collection displays a valid OMB control number. 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 Electronic
Stability Control 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 4,536 Kg (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.
Estimated Costs: NHTSA estimates that the total annual cost burden,
in U.S. dollars, will be $2,100. No additional resources would 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 would require
manufacturers of passenger cars, multipurpose passenger vehicles,
trucks, and buses with a gross vehicle weight rating of 4,536 Kg
(10,000 pounds) or less to provide motor vehicle production data for
the following three years: September 1, 2008 to August 31, 2009;
September 1, 2009 to August 31, 2010; and September 1, 2010 to August
31, 2011.
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. 126,
Electronic Stability Control 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 October 18,
2006.

H. National Technology Transfer and Advancement Act

Section 12(d) of the National Technology Transfer and Advancement
Act of 1995 (NTTAA), Public Law 104-113, 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.
The equipment requirements of this standard are based (with minor
modifications) on the SAE Surface Vehicle Information Report on
Automotive Stability Enhancement Systems J2564 Rev JUN2004 that
provides an industry consensus definition of an ESC system. However,
there is no voluntary consensus standard for ESC that contains any
specifications for a performance test.

I. Unfunded Mandates Reform Act

Section 202 of the Unfunded Mandates Reform Act of 1995 (UMRA)
requires Federal agencies to prepare a written assessment of the costs,
benefits, and other effects of proposed or final rules that include a
Federal mandate likely to result in the expenditure by State, local or
tribal governments, in the aggregate, or by the private sector, of more
than $100 million in any one year (adjusted for inflation with base
year of 1995, so currently about $118 million in 2004 dollars). 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 we
publish with the final rule an explanation why that alternative was not
adopted.
This proposal would not result in the expenditure by State, local,
or tribal governments, in the aggregate, of more than $118 million
annually, but it would result in the expenditure of that magnitude by
vehicle manufacturers and/or their suppliers.
In this proposed rule, the agency is presenting not only its
proposed regulatory approach for ESC, but also the regulatory
alternatives it has considered. In addition, as part of the public
comment process, the agency is open to suggestions regarding ways to
promote flexibility and to minimize costs of compliance, while
achieving the safety purposes of the Safe, Accountable, Flexible,
Efficient Transportation Equity Act: A Legacy for Users of 2005.

J. National Environmental Policy Act

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

K. 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.

L. Privacy Act

Please note that anyone is able to search the electronic form of
all comments received into any of our dockets by the name of the
individual submitting the comment (or signing the comment, if submitted
on behalf of an association, business, labor union, etc.). You may
review DOT's complete

[[Page 54738]]

Privacy Act Statement in the Federal Register published on April 11,
2000 (Volume 65, Number 70; pages 19477-78) or you may visit http://dms.dot.gov.
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Proposed Regulatory Text

List of Subjects in 49 CFR Parts 571 and 585

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

In consideration of the foregoing, NHTSA is proposing to amend 49
CFR parts 571 and 585 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. Section 571.101 is amended by revising Table 1 to read as
follows:

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

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3. Section 571.126 is added to read as follows:

Sec. 571.126 Standard No. 126; Electronic stability control systems.

S1. Scope. This standard establishes performance and equipment
requirements for electronic stability control (ESC) systems.
S2. Purpose. The purpose of this standard is to reduce the number
of deaths and injuries that result from crashes in which the driver
loses directional control of the vehicle.
S3. Application. This standard applies to passenger cars,
multipurpose passenger vehicles, trucks, and buses with a gross vehicle
weight rating of 4,536 kilograms (10,000 pounds) or less, according to
the phase-in schedule specified in S8 of this standard.
S4. Definitions.
Ackerman Steer Angle means the angle whose tangent is the wheelbase
divided by the radius of the turn at a very low speed.
Electronic Stability Control System or ESC System means a system
that has all of the following attributes:
(1) That augments vehicle directional stability by applying and
adjusting the vehicle brakes individually to induce correcting yaw
torques to a vehicle;
(2) That is computer controlled with the computer using a closed-
loop algorithm to limit vehicle oversteer and to limit vehicle
understeer when appropriate;
(3) That has a means to determine the vehicle's yaw rate and to
estimate its side slip;
(4) That has a means to monitor driver steering inputs, and
(5) That is operational over the full speed range of the vehicle
(except below a low-speed threshold where loss of control is unlikely).
Oversteer means a condition in which the vehicle's yaw rate is
greater than the yaw rate that would occur at the vehicle's speed as
result of the Ackerman Steer Angle.
Sideslip or side slip angle means the arctangent of the lateral
velocity of the center of gravity of the vehicle divided by the
longitudinal velocity of the center of gravity.
Understeer means a condition in which the vehicle's yaw rate is
less than the yaw rate that would occur at the vehicle's speed as
result of the Ackerman Steer Angle.
Yaw rate means the rate of change of the vehicle's heading angle
measured in degrees/second of rotation about a vertical axis through
the vehicle's center of gravity.
S5. Requirements. Subject to the phase-in set forth in S8, each
vehicle must be equipped with an ESC system that meets the requirements
specified in S5 under the test conditions specified in S6 and the test
procedures specified in S7 of this standard.
S5.1 Required Equipment. Vehicles to which this standard applies
must be equipped with an electronic stability control system that:
S5.1.1 Is capable of applying all four brakes individually and has
a control algorithm that utilizes this capability.
S5.1.2 Is operational during all phases of driving including
acceleration, coasting, and deceleration (including braking), except
when the driver has disabled ESC or the vehicle is below a low speed
threshold where loss of control is unlikely.
S5.1.3 Remains operational when the antilock brake system or
traction control system is activated.
S5.2 Performance Requirements. During each test performed under the
test conditions of S6 and the test procedure of S7.9, the vehicle with
the ESC system engaged must satisfy the stability criteria of S5.2.1
and S5.2.2, and it must satisfy the responsiveness criterion of S5.2.3
during each of those tests conducted with a steering angle amplitude of
180 degrees or greater.
S5.2.1 The yaw rate measured one second after completion of the
sine with dwell steering input (time T0 + 1 in Figure 1)
must not exceed 35 percent of the first peak value of yaw velocity
recorded after the beginning of the dwell period
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during the same test run, and
S5.2.2 The yaw rate measured 1.75 seconds after completion of the
sine with dwell steering input must not exceed 20 percent of the first
peak value of yaw velocity recorded after the beginning of the dwell
period during the same test run.
S5.2.3 The lateral displacement of the vehicle center of gravity
with respect to its initial straight path must be at least 1.83 m (6
feet) when computed 1.07 seconds after initiation of steering.
S5.2.3.1 The computation of lateral displacement is performed using
double integration with respect to time of the measurement of lateral
acceleration at the vehicle center of gravity, as expressed by the
formula:

Lateral Displacement = [int][int]Ayc.g.dt

S5.2.3.2 Time, t = 0 for the integration operation is the instant
of steering initiation.
S5.3 ESC Malfunction. The vehicle must be equipped with a telltale
that provides a warning to the driver not more than two minutes after
the occurrence of one or more malfunctions that affect the generation
or transmission of control or response signals in the vehicle's
electronic stability control system. The ESC malfunction telltale:
S5.3.1 Must be mounted inside the occupant compartment in front of
and in clear view of the driver;
S5.3.2 Must be identified by the symbol shown for ``ESC Malfunction
Telltale'' in Table 1 of Standard No. 101 (49 CFR 571.101);
S5.3.3 Must remain continuously illuminated under the conditions
specified in S5.3 for as long as the malfunction(s) exists, whenever
the ignition locking system is in the ``On'' (``Run'') position; and
S5.3.4 Except as provided in paragraph S5.3.5, each ESC malfunction
telltale must be activated as a check of lamp function either when the
ignition locking system is turned to the ``On'' (``Run'') position when
the engine is not running, or when the ignition locking system is in a
position between ``On'' (``Run'') and ``Start'' that is designated by
the manufacturer as a check position.
S5.3.5 The ESC malfunction telltale need not be activated when a
starter interlock is in operation.
S5.3.6 The ESC malfunction telltale must extinguish after the
malfunction has been corrected.
S5.3.7 The manufacturer may use the ESC malfunction telltale in a
flashing mode to indicate ESC operation.
S5.4 ESC Off Switch and Telltale. The manufacturer may include a
driver selectable switch that places the ESC system in a mode in which
it will not satisfy the performance requirements of S5.2.1, S5.2.2 and
S5.2.3 provided that:
S5.4.1 The vehicle's ESC system must always return to a mode that
satisfies the requirements of S5.1 and S5.2 at the initiation of each
new ignition cycle, regardless of what mode the driver had previously
selected. If the system has more than one mode that satisfies these
requirements, the default mode must be the mode that satisfies the
performance requirements of S5.2 by the greatest margin.
S5.4.2 The vehicle manufacturer must provide a telltale indicating
that the vehicle has been put into a mode that renders it unable to
satisfy the requirements of S5.2.1, S5.2.2 and S5.2.3.
S5.4.3 The ``ESC Off'' switch and telltale must be identified by
the symbol shown for ``ESC Off'' in Table 1 of Standard No. 101 (49 CFR
571.101).
S5.4.4 The ``ESC Off'' telltale must be mounted inside the occupant

[[Page 54750]]

compartment in front of and in clear view of the driver.
S5.4.5 The ``ESC Off'' telltale remain continuously illuminated for
as long as the ESC is in a mode that renders it unable to satisfy the
requirements of S5.2.1, S5.2.2 and S5.2.3, and
S5.4.6 Except as provided in paragraph S5.4.7, each ``ESC Off''
telltale must be activated as a check of lamp function either when the
ignition locking system is turned to the ``On'' (``Run'') position when
the engine is not running, or when the ignition locking system is in a
position between ``On'' (``Run'') and ``Start'' that is designated by
the manufacturer as a check position.
S5.4.7 The ``ESC Off'' telltale need not be activated when a
starter interlock is in operation.
S5.4.8 The ``ESC Off'' telltale must extinguish after the ESC
system has been returned to its fully functional default mode.
S6. Test Conditions.
S6.1. Ambient conditions.
S6.1.1 The ambient temperature is between 0 [deg]C (32 [deg]F) and
40 [deg]C (104 [deg]F).
S6.1.2 The maximum wind speed is no greater than 10m/s (22 mph).
S6.2. Road test surface.
S6.2.1 The tests are conducted on a dry, uniform, solid-paved
surface. Surfaces with irregularities and undulations, such as dips and
large cracks, are unsuitable.
S6.2.2 The road test surface must produce a peak friction
coefficient (PFC) of 0.9 0.05 when measured using an
American Society for Testing and 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.
S6.2.3 The test surface has a consistent slope between level and
2%. All tests are to be initiated in the direction of positive slope
(uphill).
S6.3 Vehicle conditions.
S6.3.1 The ESC system is enabled for all testing.
S6.3.2 Test Weight. The vehicle is loaded with the fuel tank filled
to at least 75 percent of capacity, and total interior load of 168 kg
(370 lbs) comprised of the test driver, approximately 59 kg (130 lbs)
of test equipment (automated steering machine, data acquisition system
and the power supply for the steering machine), and ballast as required
by differences in the weight of test drivers and test equipment.
S6.3.3 Tires. The vehicle is tested with the tires installed on the
vehicle at time of initial vehicle sale. The tires are inflated to the
vehicle manufacturer's recommended cold tire inflation pressure(s)
specified on the vehicle's placard or the tire inflation pressure
label. Tubes may be installed to prevent tire de-beading.
S6.3.4 Outriggers. Outriggers must be used for tests of Sport
Utility Vehicles (SUVs), and they are permitted on other test vehicles
if deemed necessary for driver safety.
S6.3.5 A steering machine programmed to execute the required
steering pattern must be used in S7.5.2, S7.5.3, S7.6 and S7.9.
S7. Test Procedure.
S7.1 Inflate the vehicles' tires to the cold tire inflation
pressure(s) provided on the vehicle's placard or the tire inflation
pressure label.
S7.2 Telltale bulb check. With the vehicle stationary and the
ignition locking system in the ``Lock'' or ``Off'' position, activate
the ignition locking system to the ``On'' (``Run'') position or, where
applicable, the appropriate position for the lamp check. The ESC system
must perform a check of lamp function for the ESC malfunction telltale,
and if equipped, the ``ESC Off'' telltale, as specified in S5.3.4 and
S5.4.6.
S7.3 ``ESC Off'' switch check. For vehicles equipped with an ``ESC
Off'' feature, with the vehicle stationary and the ignition locking
system in the ``Lock'' or ``Off'' position, activate the ignition
locking system to the ``On'' (``Run'') position. Activate the ``ESC
Off'' switch and verify that the ``ESC Off'' telltale is illuminated.
Turn the ignition locking system to the ``Lock'' or ``Off'' position.
Again, activate the ignition locking system to the ``On'' (``Run'')
position and verify that the ``ESC Off'' telltale has extinguished
indicating that the ESC system has been reactivated as specified in
S5.4.
S7.4 Brake Conditioning. Condition the vehicle brakes as follows:
S7.4.1 Ten stops are performed from a speed of 56 km/h (35 mph),
with an average deceleration of approximately 0.5 g.
S7.4.2 Immediately following the series of 56 km/h (35 mph) stops,
three additional stops are performed from 72 km/h (45 mph).
S7.4.3 When executing the stops in S7.4.2, sufficient force is
applied to the brake pedal to activate the vehicle's antilock brake
system (ABS) for a majority of each braking event.
S7.4.4 Following completion of the final stop in S7.4.2, the
vehicle is driven at a speed of 72 km/h (45 mph) for five minutes to
cool the brakes.
S7.5 Tire Conditioning. Condition the tires using the following
procedure to wear away mold sheen and achieve operating temperature
immediately before beginning the test runs of S7.6 and S7.9.
S7.5.1 The test vehicle is driven around a circle 30 meters (100
feet) in diameter at a speed that produces a lateral acceleration of
approximately 0.5 to 0.6 g for three clockwise laps followed by three
counterclockwise laps.
S7.5.2 Using a sinusoidal steering pattern at a frequency of 1 Hz,
a peak steering wheel angle amplitude corresponding to a peak lateral
acceleration of 0.5-0.6 g, and a vehicle speed of 56 km/h (35 mph), the
vehicle is driven through four passes performing 10 cycles of
sinusoidal steering during each pass.
S7.5.3 The steering wheel angle amplitude of the final cycle of the
final pass is twice that of the other cycles. The maximum time
permitted between all laps and passes is five minutes.
S7.6 Slowly Increasing Steer Test. The vehicle is subjected to two
series of runs of the Slowly Increasing Steer Test using a steering
pattern that increases by 13.5 degrees per second until a lateral
acceleration of approximately 0.5 g is obtained. Three repetitions are
performed for each test series. One series uses counterclockwise
steering, and the other series uses clockwise steering. The maximum
time permitted between each test run is five minutes.
S7.6.1 From the Slowly Increasing Steer tests, the quantity ``A''
is determined. ``A'' is the steering wheel angle in degrees that
produces a steady state lateral acceleration of 0.3 g for the test
vehicle. Utilizing linear regression, A is calculated, to the nearest
0.1 degrees, from each of the six Slowly Increasing Steer tests. The
absolute value of the six A's calculated is averaged and rounded to the
nearest degree to produce the final quantity, A, used below.
S7.7 After the quantity A has been determined, without replacing
the tires, the tire conditioning procedure described in S7.5 is
performed immediately prior to conducting the Sine with Dwell Test of
S7.9.
S7.8 Check that the ESC system is enabled by ensuring that the ESC
malfunction and ``ESC Off'' (if provided) telltales are not
illuminated.
S7.9 Sine with Dwell Test of Oversteer Intervention and
Responsiveness. The vehicle is subjected to two series of test runs
using a steering pattern of a sine wave at 0.7 Hz frequency with a 500
ms delay beginning at the second peak amplitude as shown in Figure 2
(the Sine with Dwell tests). One series uses counterclockwise steering
for the first half cycle, and the other series uses

[[Page 54751]]

clockwise steering for the first half cycle. The maximum time permitted
between each test run is five minutes.
S7.9.1 The steering motion is initiated with the vehicle coasting
in high gear at 80 1 km/h (50 1 mph).
S7.9.2 In each series of test runs, the steering amplitude is
increased from run to run, by 0.5A, provided that no such run will
result in a steering amplitude greater than that of the final run
specified in S7.9.4.
S7.9.3 The steering amplitude for the initial run of each series is
1.5A where A is the steering wheel angle determined in S7.6.1.
S7.9.4 The steering amplitude of the final run in each series is
the greater of 6.5A or 270 degrees.
S7.9.5 Notwithstanding S7.9.4, the test is terminated after a run
in which the vehicle does not satisfy S5.2.1 or S5.2.2.
S7.10 ESC Malfunction Detection.
S7.10.1 Simulate one or more ESC malfunction(s) by disconnecting
the power source to any ESC component, or disconnecting any electrical
connection between ESC components. When simulating an ESC malfunction,
the electrical connections for the telltale lamp(s) are not to be
disconnected.
S7.10.2 With the vehicle stationary and the ignition locking system
in the ``Lock'' or ``Off'' position, activate the ignition locking
system to the ``On'' (``Run'') position. Verify that within two minutes
of activating the ignition locking system, the ESC malfunction
indicator illuminates in accordance with S5.3.
S7.10.3 Deactivate the ignition locking system to the ``Off'' or
``Lock'' position. After a five-minute period, activate the vehicle's
ignition locking system to the ``On'' (``Run'') position. Verify that
the ESC malfunction indicator again illuminate to signal a malfunction
and remains illuminated as long as the ignition locking system is in
the ``On'' (``Run'') position.
S7.10.4 Restore the ESC system to normal operation and verify that
the telltale has extinguished.
S8 Phase-in schedule.
S8.1 Vehicles manufactured on or after September 1, 2008, and
before September 1, 2009. For vehicles manufactured on or after
September 1, 2008, and before September 1, 2009, the number of vehicles
complying with this standard must not be less than 30 percent of:
(a) The manufacturer's average annual production of vehicles
manufactured on or after September 1, 2005, and before September 1,
2008; or
(b) The manufacturer's production on or after September 1, 2008,
and before September 1, 2009.
S8.2 Vehicles manufactured on or after September 1, 2009, and
before September 1, 2010. For vehicles manufactured on or after
September 1, 2009, and before September 1, 2010, the number of vehicles
complying with this standard must not be less than 60 percent of:
(a) The manufacturer's average annual production of vehicles
manufactured on or after September 1, 2006, and before September 1,
2009; or
(b) The manufacturer's production on or after September 1, 2009,
and before September 1, 2010.
S8.3 Vehicles manufactured on or after September 1, 2010, and
before September 1, 2011. For vehicles manufactured on or after
September 1, 2010, and before September 1, 2011, the number of vehicles
complying with this standard must not be less than 90 percent of:
(a) The manufacturer's average annual production of vehicles
manufactured on or after September 1, 2007, and before September 1,
2010; or
(b) The manufacturer's production on or after September 1, 2010,
and before September 1, 2011.
S8.4 Vehicles manufactured on or after September 1, 2011. All
vehicles manufactured on or after September 1, 2011 must comply with
this standard.
S8.5 Calculation of complying vehicles.
(a) For purposes of complying with S8.1, a manufacturer may count a
vehicle if it is certified as complying with this standard and is
manufactured on or after (date to be inserted that is 60 days after
publication date of final rule), but before September 1, 2009.
(b) For purpose of complying with S8.2, a manufacturer may count a
vehicle if it:
(1)(i) Is certified as complying with this standard and is
manufactured on or after (date to be inserted that is 60 days after
date of publication of the final rule), but before September 1, 2010;
and
(ii) Is not counted toward compliance with S8.1; or
(2) Is manufactured on or after September 1, 2009, but before
September 1, 2010.
(c) For purposes of complying with S8.3, a manufacturer may count a
vehicle if it:
(1)(i) Is certified as complying with this standard and is
manufactured on or after (date to be inserted that is 60 days after
date of publication of the final rule), but before September 1, 2011;
and
(ii) Is not counted toward compliance with S8.1 or S8.2; or
(2) Is manufactured on or after September 1, 2010, but before
September 1, 2011.
S8.6 Vehicles produced by more than one manufacturer.
S8.6.1 For the purpose of calculating average annual production of
vehicles for each manufacturer and the number of vehicles manufactured
by each manufacturer under S8.1 through S8.4, a vehicle produced by
more than one manufacturer must be attributed to a single manufacturer
as follows, subject to S8.6.2:
(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 markets the vehicle, must be attributed
to the manufacturer that markets the vehicle.
S8.6.2 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 585, between the manufacturer
so specified and the manufacturer to which the vehicle would otherwise
be attributed under S8.6.1.
S8.7 Small volume manufacturers.
Vehicles manufactured during any of the three years of the
September 1, 2008 through August 31, 2011 phase-in by a manufacturer
that produces fewer than 5,000 vehicles for sale in the United States
during that year are not subject to the requirements of S8.1, S8.2,
S8.3, and S8.5
S8.8 Final-stage manufacturers and alterers.
Vehicles that are manufactured in two or more stages or that are
altered (within the meaning of 49 CFR 567.7) after having previously
been certified in accordance with Part 567 of this chapter are not
subject to the requirements of S8.1 through S8.5. Instead, all vehicles
produced by these manufacturers on or after September 1, 2012 must
comply with this standard.
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PART 585--PHASE-IN REPORTING REQUIREMENTS

4. The authority citation for part 585 continues to read as
follows:

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

5. Subpart I is added to read as follows:

Sec.
Subpart I--Electronic Stability Control System Phase-in Reporting
Requirements
585.81 Scope.
585.82 Purpose.
585.83 Applicability.
585.84 Definitions.
585.85 Response to inquiries.
585.86 Reporting requirements.
585.87 Records.
585.88 Petition to extend period to file report.

Subpart I--Electronic Stability Control System Phase-in Reporting
Requirements

Sec. 585.81 Scope.

This subpart 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 to submit a report, and maintain records related to the report,
concerning the number of such vehicles that meet the requirements of
Standard No. 126, Electronic stability control systems (49 CFR
571.126).

Sec. 585.82 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. 126 (49 CFR 571.126).

Sec. 585.83 Applicability.

This subpart 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. However, this
subpart does not apply to manufacturers whose production consists
exclusively of vehicles manufactured in two or more stages, and
vehicles that are altered after previously having been certified in
accordance with part 567 of this chapter. In addition, this subpart
does not apply to manufacturers whose production of motor vehicles for
the United States market is less than 5,000 vehicles in a production
year.

Sec. 585.84 Definitions.

For the purposes of this subpart: Production year means the 12-
month period between September 1 of one year and August 31 of the
following year, inclusive.

Sec. 585.85 Response to inquiries.

At any time prior to August 31, 2011, 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. 126 (49 CFR 571.126). The manufacturer's designation of a
vehicle as a certified vehicle is irrevocable. Upon request, the
manufacturer also must specify whether it intends to utilize carry-
forward credits, and the vehicles to which those credits relate.

Sec. 585.86 Reporting requirements.

(a) General reporting requirements. Within 60 days after the end of
the production years ending August 31, 2009, August 31, 2010, and
August 31, 2011, each manufacturer must submit a report to the National
Highway Traffic Safety Administration concerning its compliance with
Standard No. 126 (49 CFR 571.126) 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. 126 (49 CFR 571.126) 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, 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. 126 (49 CFR 571.126).
(3) Statement regarding compliance. Each manufacturer must provide
a statement regarding whether or not the manufacturer complied with the
ESC requirements as applicable to the period covered by the report, and
the basis for that statement. This statement must include an
explanation concerning the use of any carry-forward credits.
(4) 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 S8.6.2 of Standard No.
126 (49 CFR 571.126) 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. 585.87 Records.

Each manufacturer must maintain records of the Vehicle
Identification Number for each vehicle for which information is
reported under Sec. 585.86(b)(2) until December 31, 2013.

Sec. 585.88 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.
585.86(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: September 7, 2006.
Stephen R. Kratzke,
Associate Administrator for Rulemaking.
[FR Doc. 06-7598 Filed 9-14-06; 10:00 am]
BILLING CODE 4910-59-P