[Code of Federal Regulations]
[Title 49, Volume 6]
[Revised as of October 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 49CFR571.126]
[Page 457-467]
TITLE 49--TRANSPORTATION
OF TRANSPORTATION
PART 571_FEDERAL MOTOR VEHICLE SAFETY STANDARDS--Table of Contents
Subpart B_Federal Motor Vehicle Safety Standards
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, including those resulting in vehicle
rollover.
S3. Application and Incorporation by Reference.
S3.1 Application. This standard applies to passenger cars,
multipurpose passenger vehicles, trucks, and buses with a gross vehicle
weight rating of
[[Page 458]]
4,536 kilograms (10,000 pounds) or less, according to the phase-in
schedule specified in S8 of this standard.
S3.2 Incorporation by reference. ASTM E1337-90 (Reapproved 1996),
Standard Test Method for Determining Longitudinal Peak Braking
Coefficient of Paved Surfaces Using a STD Reference Test Tire, and ASTM
E1136-93 (1993), Standard Specification for a Radial Standard Reference
Test Tire, are incorporated by reference in S6.2.2 of this section. The
Director of the Federal Register has approved the incorporation by
reference of this material in accordance with 5 U.S.C. 552(a) and 1 CFR
Part 51. Copies of ASTM E1337-90 (rev. 1996) and ASTM E1136-93 (1993)
may be obtained from the ASTM Web site at http://www.astm.org, or by
contacting ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-
2959. Copies of ASTM E1337-90 (Reapproved 1996) and ASTM E1136-93 (1993)
may be inspected at NHTSA's Office of Rulemaking, 400 Seventh Street,
SW., Washington, DC 20590, or at the National Archives and Records
Administration (NARA). For information on the availability of this
material at NARA, call 202-741-6030, or go to: http://www.archives.gov/
federal--register/code--of--federal--regulations/ibr--locations.html.
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 brake torques individually to induce a correcting
yaw moment 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;
(3) That has a means to determine the vehicle's yaw rate and to
estimate its side slip or side slip derivative with respect to time;
(4) That has a means to monitor driver steering inputs;
(5) That has an algorithm to determine the need, and a means to
modify engine torque, as necessary, to assist the driver in maintaining
control of the vehicle, and
(6) That is operational over the full speed range of the vehicle
(except at vehicle speeds less than 15 km/h (9.3 mph) or when being
driven in reverse).
Lateral Acceleration means the component of the vector acceleration
of a point in the vehicle perpendicular to the vehicle x axis
(longitudinal) and parallel to the road plane.
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 a
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 brake torques individually to all four
wheels 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, the vehicle speed is below 15 km/h
(9.3 mph), or the vehicle is being driven in reverse.
S5.1.3 Remains capable of activation even if the antilock brake
system or traction control system is also activated.
[[Page 459]]
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 commanded steering wheel
angle of 5A or greater, where A is the steering wheel angle computed in
S7.6.1.
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 rate recorded after the
steering wheel angle changes sign (between first and second peaks) (Peak
in Figure 1) 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 rate recorded after the steering wheel angle changes
sign (between first and second peaks) 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) for vehicles with a GVWR of 3,500kg (7,716 lb) or less, and 1.52 m
(5 feet) for vehicles with a GVWR greater than 3,500 kg (7,716 lb) when
computed 1.07 seconds after the Beginning of Steer (BOS). BOS is defined
in S7.11.6.
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:
[GRAPHIC] [TIFF OMITTED] TR06AP07.008
S5.2.3.2 Time t = 0 for the integration operation is the instant of
steering initiation, known as the Beginning of Steer (BOS). BOS is
defined in S7.11.6.
S5.3 ESC Malfunction. The vehicle must be equipped with a telltale
that provides a warning to the driver of 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 As of September 1, 2011, must be mounted inside the occupant
compartment in front of and in clear view of the driver;
S5.3.2 As of September 1, 2011, must be identified by the symbol
shown for ``ESC Malfunction Telltale'' or the specified words or
abbreviations listed in Table 1 of Standard No. 101 (49 CFR 571.101);
S5.3.3 As of September 1, 2011, except as provided in paragraph
S5.3.4, the ESC malfunction telltale must illuminate only when a
malfunction(s) exists and 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 As of September 1, 2011, 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 requirement S5.3.4 does not apply to telltales shown in a
common space.
S5.3.7 The ESC malfunction telltale must extinguish at the next
ignition cycle after the malfunction has been corrected.
S5.3.8 The manufacturer may use the ESC malfunction telltale in a
flashing mode to indicate ESC operation.
S5.3.9 Prior to September 1, 2011, a disconnection of the power to
the ESC electronic control unit may be indicated by the ABS malfunction
telltale instead of the ESC malfunction telltale, and a disconnection of
the ``ESC Off'' control need not illuminate the ESC malfunction
telltale.
S5.4. ESC Off and Other System Controls. The manufacturer may
include an ``ESC Off'' control whose only purpose
[[Page 460]]
is to place the ESC system in a mode in which it will no longer satisfy
the performance requirements of S5.2.1, S5.2.2 and S5.2.3. Manufacturers
may also provide controls for other systems that have an ancillary
effect upon ESC operation. Controls of either kind that place the ESC
system in a mode in which it will no longer satisfy the performance
requirements of S5.2.1, S5.2.2 and S5.2.3 are permitted, 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 except if that mode is specifically for enhanced traction
during low-speed, off-road driving and is entered by the driver using a
mechanical control that cannot be automatically reset electrically. 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 As of September 1, 2011, a control whose only purpose is to
place the ESC system in a mode in which it will no longer satisfy the
performance requirements of S5.2.1, S5.2.2 and S5.2.3 must be identified
by the symbol shown for ``ESC Off'' in Table 1 of Standard No. 101 (49
CFR 571.101) or the text, ``ESC Off'' as listed under ``Word(s) or
Abbreviations'' in Table 1 of Standard No. 101 (49 CFR 571.101).
S5.4.3 A control for another system that has the ancillary effect of
placing the ESC system in a mode in which it no longer satisfies the
performance requirements of S5.2.1, S5.2.2, and S5.2.3 need not be
identified by the ``ESC Off'' identifiers in Table 1 of Standard No. 101
(49 CFR 571.101), but the ESC status must be identified by the ``ESC
Off'' telltale in accordance with S5.5, as of September 1, 2011.
S5.5 ESC Off Telltale
S5.5.1 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, if such a mode is
provided.
S5.5.2 As of September 1, 2011, the ``ESC Off'' telltale must be
identified by the symbol shown for ``ESC Off'' in Table 1 of Standard
No. 101 (49 CFR 571.101) or the text, ``ESC Off'' as listed under
``Word(s) or Abbreviations'' in Table 1 of Standard No. 101 (49 CFR
571.101).
S5.5.3 As of September 1, 2011, the ``ESC Off'' telltale must be
mounted inside the occupant compartment in front of and in clear view of
the driver.
S5.5.4 The ``ESC Off'' telltale must 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
S5.5.5 Notwithstanding S5.3.1(e) of 49 CFR 571.101, the vehicle
manufacturer may use the ``ESC Off'' telltale to indicate an ESC level
of function other than the fully functional default mode even if the
vehicle would meet S5.2.1, S5.2.2 and S5.2.3 at that level of ESC
function.
S5.5.6 As of September 1, 2011, except as provided in paragraph
S5.5.7 and S5.5.8, 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.
S5.5.7 The ``ESC Off'' telltale need not be activated when a starter
interlock is in operation.
S5.5.8 The requirement S5.5.6 does not apply to telltales shown in a
common space.
S5.5.9 The ``ESC Off'' telltale must extinguish after the ESC system
has been returned to its fully functional default mode.
S5.6 ESC System Technical Documentation. To ensure a vehicle is
equipped with an ESC system that meets the definition of ``ESC System''
in S4, the vehicle manufacturer must make available to the agency, upon
request, the following documentation:
S5.6.1 A system diagram that identifies all ESC system hardware. The
diagram must identify what components are used to generate brake torques
at each wheel, determine vehicle yaw rate, estimated side slip or the
side slip derivative and driver steering inputs.
[[Page 461]]
S5.6.2 A written explanation describing the ESC system basic
operational characteristics. This explanation must include a discussion
on the system's capability to apply brake torques at each wheel and how
the system modifies engine torque during ESC system activation. The
explanation must also identify the vehicle speed range and the driving
phases (acceleration, deceleration, coasting, during activation of the
ABS or traction control) under which the ESC system can activate.
S5.6.3 A logic diagram that supports the explanation provided in
S5.6.2.
S5.6.4 Specifically for mitigating vehicle understeer, a discussion
of the pertinent inputs to the computer or calculations within the
computer and how its algorithm uses that information and controls ESC
system hardware to limit vehicle understeer.
S6. Test Conditions.
S6.1 Ambient conditions.
S6.1.1 The ambient temperature is between 7 [deg]C (45 [deg]F) and
40 [deg]C (104 [deg]F).
S6.1.2 The maximum wind speed is no greater than 10 m/s (22 mph) for
passenger cars and 5 m/s (11 mph) for multipurpose passenger vehicles,
trucks and buses.
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 when measured using an American Society for
Testing and Materials (ASTM) E1136-93 (1993) standard reference test
tire, in accordance with ASTM Method E 1337-90 (Reapproved 1996), at a
speed of 64.4 km/h (40 mph), without water delivery. (These standards
are here incorporated by reference as explained in S3.2 above.)
S6.2.3 The test surface has a consistent slope between level and 1%.
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. Where
required, ballast shall be placed on the floor behind the passenger
front seat or if necessary in the front passenger foot well area. All
ballast shall be secured in a way that prevents it from becoming
dislodged during test conduct.
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 testing trucks,
multipurpose passenger vehicles, and buses. Vehicles with a baseline
weight under 2,722 kg (6,000 lbs) must be equipped with ``standard''
outriggers and vehicles with a baseline weight equal to or greater than
2,722 kg (6,000 lbs) must be equipped with ``heavy'' outriggers. A
vehicle's baseline weight is the weight of the vehicle delivered from
the dealer, fully fueled, with a 73 kg (160 lb) driver. Standard
outriggers shall be designed with a maximum weight of 32 kg (70 lb) and
a maximum roll moment of inertia of 35.9 kg-m\2\ (26.5 ft-lb-sec\2\).
Heavy outriggers shall be designed with a maximum weight of 39 kg (86
lb) and a maximum roll moment of inertia of 40.7 kg-m\2\ (30.0 ft-lb-
sec\2\).
S6.3.5 Automated steering machine. 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. The steering machine shall be capable of supplying
steering torques between 40 to 60 Nm (29.5 to 44.3 lb-ft). The steering
machine must be able to apply these torques when operating with steering
wheel velocities up to 1200 degrees per second.
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.
[[Page 462]]
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
malfunction telltale must be activated as a check of lamp function, as
specified in S5.3.4, and if equipped, the ``ESC Off'' telltale must also
be activated as a check of lamp function, as specified in S5.5.6. The
telltale bulb check is not required for a telltale shown in a common
space as specified in S5.3.6 and S5.5.8.
S7.3 ``ESC Off'' control check. For vehicles equipped with an ``ESC
Off'' control, 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'' control and verify that the ``ESC Off'' telltale is illuminated,
as specified in S5.5.4. 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 S5.4.1.
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 constant
vehicle speed of 80 2 km/h (50 1 mph) and 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 (corrected using the methods specified
in S7.11.3) 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 0.1 degrees 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.
Initiation of the first Sine with Dwell test series shall begin within
two hours after completion of the Slowly Increasing Steer tests of S7.6.
[[Page 463]]
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 clockwise steering
for the first half cycle. The vehicle is provided a cool-down period
between each test run of 90 seconds to five minutes, with the vehicle
stationary.
S7.9.1 The steering motion is initiated with the vehicle coasting in
high gear at 80 2 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, provided the calculated magnitude of
6.5A is less than or equal to 300 degrees. If any 0.5A increment, up to
6.5A, is greater than 300 degrees, the steering amplitude of the final
run shall be 300 degrees.
S7.9.5 Upon completion of the two series of test runs, post
processing of yaw rate and lateral acceleration data is done as
specified in S7.11.
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 (with the vehicle power off). When
simulating an ESC malfunction, the electrical connections for the
telltale lamp(s) are not to be disconnected.
S7.10.2 With the vehicle initially stationary and the ignition
locking system in the ``Lock'' or ``Off'' position, activate the
ignition locking system to the ``Start'' position and start the engine.
Place the vehicle in a forward gear and obtain a vehicle speed of 48
8 km/h (30 5 mph). Drive
the vehicle for at least two minutes including at least one left and one
right turning maneuver. Verify that within two minutes of obtaining this
vehicle speed the ESC malfunction indicator illuminates in accordance
with S5.3.
S7.10.3 Stop the vehicle, 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 ``Start'' position and
start the engine. Verify that the ESC malfunction indicator again
illuminates to signal a malfunction and remains illuminated as long as
the engine is running or until the fault is corrected.
S7.10.4 Deactivate the ignition locking system to the ``Off'' or
``Lock'' position. Restore the ESC system to normal operation, activate
the ignition system to the ``Start'' position and start the engine.
Verify that the telltale has extinguished.
S7.11 Post Data Processing--Calculations for Performance Metrics.
Yaw rate and lateral displacement measurements and calculations must be
processed utilizing the following techniques:
S7.11.1 Raw steering wheel angle data is filtered with a 12-pole
phaseless Butterworth filter and a cutoff frequency of 10Hz. The
filtered data is then zeroed to remove sensor offset utilizing static
pretest data.
S7.11.2 Raw yaw rate data is filtered with a 12-pole phaseless
Butterworth filter and a cutoff frequency of 6Hz. The filtered data is
then zeroed to remove sensor offset utilizing static pretest data.
S7.11.3 Raw lateral acceleration data is filtered with a 12-pole
phaseless Butterworth filter and a cutoff frequency of 6Hz. The filtered
data is then zeroed to remove sensor offset utilizing static pretest
data. The lateral acceleration data at the vehicle center of gravity is
determined by removing the effects caused by vehicle body roll and by
correcting for sensor placement via use of coordinate transformation.
For data collection, the lateral accelerometer shall be located as close
as possible to the position of the vehicle's
[[Page 464]]
longitudinal and lateral centers of gravity.
S7.11.4 Steering wheel velocity is determined by differentiating the
filtered steering wheel angle data. The steering wheel velocity data is
then filtered with a moving 0.1 second running average filter.
S7.11.5 Lateral acceleration, yaw rate and steering wheel angle data
channels are zeroed utilizing a defined ``zeroing range.'' The methods
used to establish the zeroing range are defined in S7.11.5.1 and
S7.11.5.2.
S7.11.5.1 Using the steering wheel rate data calculated using the
methods described in S7.11.4, the first instant steering wheel rate
exceeds 75 deg/sec is identified. From this point, steering wheel rate
must remain greater than 75 deg/sec for at least 200 ms. If the second
condition is not met, the next instant steering wheel rate exceeds 75
deg/sec is identified and the 200 ms validity check applied. This
iterative process continues until both conditions are ultimately
satisfied.
S7.11.5.2 The ``zeroing range'' is defined as the 1.0 second time
period prior to the instant the steering wheel rate exceeds 75 deg/sec
(i.e., the instant the steering wheel velocity exceeds 75 deg/sec
defines the end of the ``zeroing range'').
S7.11.6 The Beginning of Steer (BOS) is defined as the first
instance filtered and zeroed steering wheel angle data reaches -5
degrees (when the initial steering input is counterclockwise) or +5
degrees (when the initial steering input is clockwise) after time
defining the end of the ``zeroing range.'' The value for time at the BOS
is interpolated.
S7.11.7 The Completion of Steer (COS) is defined as the time the
steering wheel angle returns to zero at the completion of the Sine with
Dwell steering maneuver. The value for time at the zero degree steering
wheel angle is interpolated.
S7.11.8 The second peak yaw rate is defined as the first local yaw
rate peak produced by the reversal of the steering wheel. The yaw rates
at 1.000 and 1.750 seconds after COS are determined by interpolation.
S7.11.9 Determine lateral velocity by integrating corrected,
filtered and zeroed lateral acceleration data. Zero lateral velocity at
BOS event. Determine lateral displacement by integrating zeroed lateral
velocity. Zero lateral displacement at BOS event. Lateral displacement
at 1.07 seconds from BOS event is determined by interpolation.
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 55 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 75 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 95 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
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this standard and is manufactured on or after June 5, 2007, 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 June 5, 2007, 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 June 5, 2007, 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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[72 FR 17310, Apr. 6, 2007, as amended at 72 FR 34410, June 22, 2007]