[Federal Register Volume 67, Number 141 (Tuesday, July 23, 2002)]
[Proposed Rules]
[Pages 48117-48129]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-18477]
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DEPARTMENT OF TRANSPORTATION
National Highway Traffic Safety Administration
49 CFR Part 571
[DOT Docket No. NHTSA-02-12845]
RIN: 2127-AH71
Federal Motor Vehicle Safety Standards; Accelerator Control
Systems
AGENCY: National Highway Traffic Safety Administration (NHTSA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: This document proposes to revise the Federal motor vehicle
safety standard for accelerator control systems. The standard seeks to
reduce deaths and injuries resulting from engine overspeed caused by
malfunctions in these systems. When the standard was originally drafted
and issued, most systems were mechanical. Now, increasing numbers of
systems are electronic, electric or hybrid. The revised standard would
explicitly apply to these systems, and contain provisions addressing
the distinctive failure modes of each type of system.
DATES: You should submit your comments early enough to ensure that
Docket Management receives them not later than September 23, 2002.
ADDRESSES: You should mention the docket number of this document in
your comments and submit your comments in writing to: Docket
Management, Room PL-401, 400 Seventh Street, SW., Washington, DC,
20590.
You may call the Docket at 202-366-9324. You may visit the Docket
from 10 a.m. to 5 p.m., Monday through Friday.
FOR FURTHER INFORMATION CONTACT: For non-legal issues, you may call Mr.
Michael Pyne, Office of Crash Avoidance Standards at (202) 366-4171.
His FAX number is (202) 493-2739.
For legal issues, you may call Ms. Dorothy Nakama, Office of the
Chief Counsel at (202) 366-2992. Her FAX number is (202) 366-3820.
You may send mail to both of these officials at National Highway
Traffic Safety Administration, 400 Seventh St., SW., Washington, DC,
20590.
SUPPLEMENTARY INFORMATION:
Table of Contents
I. Background ``History of Standard No. 124
II. Standard No. 124 and Electronic Accelerator Control Systems
III. Why We Propose to Amend Standard No. 124
IV. 1995 Request for Comments
V. 1997 Public Technical Workshop
VI. Notice of Proposed Rulemaking
A. Scope of the Proposed Revision of Standard No. 124
B. Components of an Accelerator Control System
1. Connective Components of an Air or Fuel-Throttled Engine's
Accelerator Control System
2. Connective Components of an Electric Propulsion Motor
C. Inadequacy of Present Performance Criteria
D. Criteria for Return to Idle in Normal Operation
1. Diesel Engines
2. HEUI Injectors with Multiple ``Throttles'
3. Electric Motors
4. Response Time Requirements Will be Retained
E. Fail-Safe Performance Criteria
1. Alternative Fail-Safe Performance Tests for Air-Throttled
Engines
2. Alternative Fail-Safe Performance Tests for Fuel-Throttled
Engines
3. Alternative Fail-Safe Performance Tests for Electric Vehicles
4. Alternative Fail-Safe Performance Tests for Hybrid Vehicles
F. Irrevocable Selection of Test to Which a Vehicle is Certified
G. Definition of ``Idle State''
H. Handling Limp Home Strategies
I. Severance and Disconnection
J. Two Sources of Energy for Returning Throttle to Idle
K. Stabilization of Engine Power and Idle State Tolerances
VII. Leadtime
VIII. Regulatory Analyses and Notices
A. Executive Order 12866 and DOT Regulatory Policies and
Procedures
B. Executive Order 13132 (Federalism)
C. Executive Order 13045 (Economically Significant Rules
Disproportionately Affecting Children)
D. Executive Order 12778 (Civil Justice Reform)
E. Regulatory Flexibility Act
F. National Environmental Policy Act
G. Paperwork Reduction Act
H. National Technology Transfer and Advancement Act
I. Unfunded Mandates Reform Act
J. Data Quality Guidelines
K. Plain Language
L. Regulation Identifier Number (RIN)
Proposed Regulatory Text
I. Background--History of Standard No. 124
The purpose of Standard No. 124, Accelerator Control Systems, 49
CFR 571.124, is to reduce deaths and injuries resulting from failures
of a vehicle's accelerator control system. Since 1972, Standard No. 124
has specified requirements for ensuring the return of a vehicle's
throttle to the idle position under each of the following
circumstances: (1) When the driver removes the actuating force (usually
the driver's foot) from the accelerator control (usually the
accelerator pedal), and (2) when there is a severance or disconnection
in the accelerator control system (``fail-safe'' operation). Standard
No. 124 applies to passenger cars, multipurpose passenger vehicles,
trucks, and buses.
Standard No. 124 at S5.1 requires that each vehicle have ``at least
two sources of energy,'' each independently capable of returning the
throttle to the idle position, within the time specified in paragraph
S5.3, from any accelerator position or speed whenever the driver
removes the actuating force. The Standard defines the throttle as ``the
component of the fuel metering device that connects to the driver-
operated accelerator control system and that by input from the driver-
operated accelerator control system controls engine speed.''
Paragraph S5.2 requires that the throttle return to idle ``whenever
any one component of the accelerator control system is disconnected or
severed at a single point.'' This requirement must be met within the
time specified in paragraph S5.3.
Paragraph S5.3 requires the throttle to return to idle within one
second for vehicles with a gross vehicle weight rating (GVWR) of 10,000
pounds or less and within two seconds for vehicles with GVWRs greater
than 10,000 pounds. The return-to-idle time is increased to three
seconds for any vehicle that is exposed to ambient air at 0 degrees to
-40 degrees Fahrenheit during the test or for any portion of a 12-hour
conditioning period.
II. Standard No. 124 and Electronic Accelerator Control Systems
When originally promulgated, the definitions and requirements of
Standard No. 124 were easy to apply because they were based on the
then-universal mechanical control systems. The ``throttle'' of a
gasoline engine was the carburetor shaft that opened and closed the air
intake passages. The ``throttle'' of a diesel engine was the control
rod or rack that controlled fuel flow to the high pressure injectors.
The two energy sources were simply two return springs acting on the
linkage between the accelerator pedal and the throttle. If at least one
of those springs
[[Page 48118]]
were connected directly to the carburetor or to the diesel fuel
injection rack, it would cause the throttle to return to idle in the
event of a disconnection of the pedal linkage. If the disconnection
occurred at one of the springs, the other would permit continued driver
control.
Since Standard No. 124 was issued, electronic engine controls using
computer systems have become commonplace. Electronic accelerator
linkages have become so common on large trucks that a mechanical
accelerator linkage controlling a fuel injection rack is now rare on
those vehicles. Already the norm for large trucks, fully electronic
accelerator controls, or ``throttle-by-wire'' systems, have recently
been introduced on light trucks and passenger cars. In these systems,
the driver's pressure on the accelerator pedal is sensed electronically
and is transmitted to the device on the engine which controls engine
power.
The introduction of electronic systems led to questions about
whether and how they were regulated by Standard No. 124. Isuzu Motors
America, Inc. (Isuzu) wrote first, asking a variety of questions
concerning electronic systems. Isuzu suggested that some of the
language in the standard seemed more appropriate for mechanical
accelerator systems than for electronic ones. Its central question was
whether the standard applies to electronic systems. Among other
questions, Isuzu asked whether a severance in electric wires in its
electronic accelerator control system is a severance within the meaning
of S5.2 of the standard. Isuzu expressed its belief that, because the
electric wires were not a ``moving part,'' the answer should be no.
In an August 8, 1988 interpretation letter to Isuzu, NHTSA
disagreed with Isuzu's position. NHTSA stated that the standard, which
refers generally to accelerator control systems, instead of
specifically to ``mechanical'' systems, applies to electronic
accelerator control systems. The agency interpreted Standard No. 124's
requirement that the throttle must return to idle ``whenever any one
component of the accelerator control system is disconnected or severed
at a single point,'' to include all severances or disconnections of any
component of the accelerator control system as it is defined in the
standard, not just disconnections of moving parts. NHTSA subsequently
reiterated its position that Standard No. 124 applies to electronic
accelerator controls in letters of November 9, 1988 to Caterpillar,
Inc.; September 23, 1992 to Bendix Heavy Vehicle Systems; and August 7,
1996 to Philips Research Lab Aachen.
Although the agency has applied Standard No. 124 to electronic
accelerator control systems on several occasions, manufacturers
continue to question whether the Standard applies to these systems. One
correspondent assumed, incorrectly, that since electronic accelerator
control systems do not include springs and linkages beyond the pedal
assembly as described in Standard No. 124, the electronic components of
such systems were not regulated. Similarly, other correspondents have
believed Standard No. 124 to mean simply that two return springs should
be placed on the accelerator pedal assembly.
In response, the agency has recited in its interpretation letters
the requirement that the sources of energy must be capable of returning
the throttle to idle in the event of any single severance or
disconnection. NHTSA noted that although the use of two springs on the
pedal assembly may represent good pedal design, it does not
intrinsically overcome a disconnection anywhere within an electronic
accelerator control system. Good pedal design by itself does not
provide an electronic accelerator control system with the same degree
of fail-safe operation provided in a mechanical system by having a
return spring directly on the throttle or fuel injection rack. The
springs on the throttle or fuel injection rack in a traditional
mechanical system could overcome an accelerator control disconnection
and return the throttle to idle regardless of where in the system the
disconnection occurred. In an electronic accelerator control system,
disconnection or severance of the wiring between the pedal position
sensor and the engine control processor, between the engine control
processor and the throttle on the engine, and in the power and ground
connections to the engine control processor are failures analogous to
the disconnections of mechanical linkages. Those failures cannot be
addressed by focusing solely on the pedal.
Some parties have recognized the analogy between wire severance or
disconnection and mechanical linkage severance or disconnection but,
because of the standard's lack of specificity, still found it necessary
to ask whether the standard applies to short circuits of connecting
wires as well as open disconnections.
III. Why We Propose to Amend Standard No. 124
The need for interpretation letters drawing analogies between
traditional mechanical components and new electronic systems results
from the present regulatory language that reflects the design of
mechanical systems. Now that electronic accelerator controls are
becoming increasingly commonplace, there is a growing need to revise
Standard 124 to address electronic control systems explicitly. As an
example, although the term ``throttle'' is not ambiguous for mechanical
systems, it loses its clarity when applied to a diesel engine with
electronically controlled fuel injectors because the functional
throttle position is the product of the combined duty cycle of the
engine's injectors and thus cannot be measured by observing the
position of any single component. Regulatory language that specifically
addresses ``throttle'' in the context of electronic controls systems
would help make it explicit not only that Standard No. 124 applies to
electronic control systems, but also how it applies to them.
We are also concerned that regulating electronic systems by drawing
analogies to mechanical systems has the undesirable effect of limiting
the permissible responses to failures in electronic systems to only the
fail-safe modes that are possible with mechanical systems. The only
response that the present standard recognizes for fail-safe performance
is the return of the throttle exactly to the idle position. However,
the real issue is the return of engine power to a benign idle state as
a fail-safe response to a disconnection in the accelerator control
system. Electronic engine controls can reduce the engine power through
control of fuel pressure, spark timing, and other factors independent
of throttle position. It is neither necessary nor desirable to limit
the ways in which fail-safe performance can be achieved by electronic
accelerator controls systems.
IV. 1995 Request for Comments
In a Request for Comments published in the Federal Register on
December 4, 1995 (60 FR 62061), NHTSA introduced the subject of
revising Standard No. 124 to add specific provisions for electronic
accelerator controls. The notice asked for explanations of the
principles of operation and fail-safe provisions of systems in use. It
also presented for discussion the idea of identifying each potential
failure mode of an electronic accelerator control system and a
corresponding fail-safe requirement practicable for each failure mode,
as
[[Page 48119]]
well as the alternative idea of a redundant engine controller active
only at the idle position of the accelerator pedal.
In general, the comments of vehicle and engine manufacturers did
not address the specific questions in the notice. Instead, they voiced
a preference for rescinding the standard altogether, suggesting that
market forces and litigation pressure are sufficient to assure fail-
safe performance without a Federal motor vehicle safety standard.
However, they also commented that, should the agency disagree about
rescission, a standard specifying fail-safe performance in the least
design-specific terms would be preferable to the requirements suggested
in the Request for Comments.
V. 1997 Public Technical Workshop
On May 20, 1997, NHTSA held a public technical workshop on
electronic accelerator controls, with the participation of the Truck
Manufacturers Association (TMA) and the organization then known as the
American Automobile Manufacturers Association (AAMA). Both
organizations made brief presentations about the general operating
principles of electronic accelerator controls and emphasized that there
had been no safety-related developments concerning electronic
accelerator controls to justify applying Standard No. 124 to such
systems, which they would consider an increase in the scope of the
standard.
AAMA identified the following problems in defining the safety
performance of electronic accelerator controls: How to define ``idle'';
how to define ``severance'' and ``disconnection''; how to handle ``limp
home'' strategies; how to specify a test procedure; and how to specify
where in the engine management system disconnections and severances
should be considered failures of the accelerator control system. TMA
stressed that the idle speed is dependent on environmental and
operating conditions and is somewhat variable by necessity; therefore,
``return to idle'' must refer to a range of operation identified by the
manufacturer as appropriate for conditions and not simply as a throttle
position.
During the meeting, we responded to these comments by stating that
we were seeking neither to increase nor decrease the scope of Standard
No. 124, but to have a standard that was clear and adequate in its
application to electronic accelerator controls and that was as
performance-oriented as possible. We agreed that existing electronic
accelerator control systems appeared to be safe and that present
regulation by analogy was inadequate only in its lack of clarity
regarding its applicability and its exclusion of new fail-safe
strategies. We invited the attendees, and especially the industry
associations, to provide specific recommendations for regulatory text
that would address the difficulties in updating Standard No. 124.
TMA and AAMA each submitted suggested regulatory text amending the
Standard to accommodate electronic accelerator controls. Their
comments, including their suggestions about text, may be viewed in the
docket for the present notice. As discussed in the next section, our
proposed revision of Standard No. 124 draws on their suggestions, but
differs in several important ways.
VI. Notice of Proposed Rulemaking
A. Scope of the Proposed Revision of Standard No. 124
In response to the industry's concerns, we seek to ensure that the
scope of the proposed standard remains the same as that of the present
standard. Nothing in this proposed rule intentionally changes the scope
of Standard No. 124. For example, where the present standard applies
only to single-point severances or disconnections such as the
disconnection of one end of a throttle cable, the proposed standard
also is limited to single-point severances and disconnections such as
unhooking one electrical connector or cutting a conductor at one
location. The proposal does not attempt to make the requirements more
stringent by requiring fail-safe performance when multiple severances
or disconnections occur simultaneously.
Electronic accelerator controls are more complex than mechanical
accelerator controls. The revised standard in this proposal appears
correspondingly more complex than the present standard, but the added
regulatory text is for the purpose of greater specificity. Lack of
specificity in the present standard has led some parties to believe
that electronic accelerator controls are regulated less comprehensively
than mechanical accelerator controls. This amendment also enhances
design freedom and avoids greater burden on manufacturers by addressing
types of accelerator controls other than mechanical air throttles and
by allowing fail-safe strategies other than return of the air throttle
to a mechanical stop.
The agency's view of the scope of the Standard differs from the
suggestions made in 1997 by TMA and AAMA with regard to whether an
electronic accelerator control system is comprised only of the pedal
position sensor and its wiring to the input of the engine control
module (ECM), or whether it extends beyond the ECM to include
connections to the actual throttling device on the engine.
AAMA argued that the ECM itself should be considered the throttle.
We do not agree with this position. We believe that the throttle is the
air intake valve, or throttle plate (which is housed in the ``throttle
body''), for a conventional gasoline engine. In versions of this engine
with mechanical accelerator controls, a cable or linkage that is
clearly part of the accelerator control system operates the air intake
valve. If the cable or linkage is disconnected at the air intake valve,
the present standard requires the air intake valve to close by means of
a spring or other source of energy. Versions of this engine with
electronic accelerator controls have a similar throttle to which is
added an electric actuator to open and close the air intake valve. If
the electrical connection between the ECM and the electric actuator of
the air intake valve were disconnected, no corresponding fail-safe
action would be required in AAMA's view of the scope of the standard.
This view is contrary to the analogies between mechanical and
electronic systems that form the basis of the legal interpretations of
the present standard.
B. Components of an Accelerator Control System
The present standard refers to the accelerator control system in
general terms, defining it in S4.1 as ``all vehicle components, except
the fuel metering device, that regulate engine speed in direct response
to the movement of the driver-operated control and that return the
throttle to the idle position upon release of the actuating force.''
In this proposed rule, we treat an accelerator control system
(ACS), whether electronic or mechanical, as a series of linked
components extending from the driver-operated control to the fuel
metering device on the engine or motor. A severance at any one point in
the system should not result in losing control of engine power.
Electronic systems with wires, relays, control modules, and electric
actuators joining the accelerator pedal to the throttle or injectors on
the engine are analogous to mechanical systems in which levers,
linkages, pivots, cables, and springs serve the same purpose. This
definition also applies to an ACS that mixes mechanical and electronic
components.
[[Page 48120]]
In a mechanical control system, it is reasonably clear which
vehicle components comprise the ACS, and it is therefore not difficult
to apply the definition used in the present standard. Electronic ACSs
are less easily defined than mechanical ones because a variety of
components can influence engine speed without being in the direct line
of action between the accelerator pedal and the throttling device on
the engine.
One possible approach to defining an electronic ACS would be to
list in the standard exactly which components, connections, modules,
etc., make up an ACS and are subject to the fail-safe requirements.
This explicit approach would provide for a high degree of clarity, but
would tend to produce a standard lacking flexibility. There is the
possibility that any connective component omitted from specific mention
in the standard would be excluded from regulation, whether
intentionally or not.
The alternative regulatory approach, and the one that we have
chosen to employ in the proposed standard, is to specify in general
terms the connective components that are regulated. This general
approach lends a high degree of flexibility to the standard by leaving
open the possibility that the regulatory language can be adapted to new
technology.
We agree with TMA and AAMA that there is no evidence of a new
safety problem requiring an increase in the scope of Standard No. 124.
Since the scope of the fail-safe requirements is still limited to the
``connective components'' of accelerator control systems, we believe
the proposed standard adheres to the scope of the existing standard.
Nevertheless, this notice lists some common components of an ACS to
illustrate the intent of the proposed standard and to make it clear
that these components are considered part of the ACS. The following
paragraphs list some of the connective components of electronic
accelerator control systems subject to the fail-safe requirements of
Standard No. 124, as well as elements of mechanical accelerator control
systems always understood to be covered by Standard No. 124.
1. Connective Components of an Air or Fuel-Throttled Engine's ACS--
For an air-or fuel-throttled engine, the critical connective components
of the accelerator control system are: (1) The springs or other sources
of energy that return the driver-operated control and the throttle to
the idle position; (2) the linkages, rods, cables or equivalent
components which are actuated by the driver-operated control; (3) the
linkages, rods, cables or equivalent components which actuate the
throttle; (4) the hoses which connect hydraulic or pneumatic systems
within an accelerator control system; (5) the connectors and individual
conductors in the electrical wiring which connect the driver-operated
control to the engine control processor; (6) the connectors and
individual conductors in the electrical wiring which connect the engine
control module (ECM) to the throttle or other fuel-metering device; and
(7) the connectors and individual conductors in the electrical wiring
which connect the ECM to the electrical power source and electrical
ground.
With regard to the ECM itself, the agency believes that an
electronic accelerator control system necessarily includes the ECM as
one component. However, we view the fail-safe requirements of the
Standard as pertaining to the connective elements rather than the
internal elements of the ECM. We agree with TMA and AAMA that internal
elements of the ECM are analogous in function to the internal elements
of a carburetor or fuel injection distributor, which have never been
included in the fail-safe requirements of the Standard. The wiring and
connectors between the pedal position sensor and the ECM, the wiring
and connectors between the ECM and the physical fuel-metering device on
the engine, and the power and ground connections to the ECM are all
connective rather than internal elements.
2. Connective Components of an Electric Propulsion Motor--For an
electric motor, the critical connective components of an accelerator
control system are: (1) The springs or other sources of energy that
return the driver-operated control and the motor speed controller to
the idle position; (2) the linkages, rods, cables or equivalent
components which are actuated by the driver-operated control; (3) the
linkages, rods, cables or equivalent components which actuate the motor
speed controller; (4) the hoses which connect hydraulic or pneumatic
systems within an accelerator control system; (5) the connectors and
individual conductors in the electrical wiring which connect the
driver-operated control to the motor speed controller or motor control
processor; (6) the connectors and individual conductors in the
electrical wiring which connect the motor control processor to the
motor speed controller; (7) the connectors and individual conductors in
the electrical wiring which connect the motor control processor to the
electrical power and electrical ground; and (8) the connectors and
individual conductors in the electrical wiring from the motor speed
controller to the electric traction motor.
C. Inadequacy of Present Performance Criteria
At present, Standard No. 124's performance criteria are based on
measuring the position of the ``throttle,'' which is defined as the
component of the fuel metering device that connects to the driver-
operated accelerator control to regulate engine power and speed. The
advantage of this indicator of accelerator control operation is that it
is simple to measure. The lag time of the actual change in engine power
and speed, which can be considerable because it depends on engine
characteristics such as compression and rotational inertia and test
conditions such as load and temperature, does not complicate the
determination of whether the throttle returns to idle within the
required time. The typical throttle of a gasoline engine is the
``butterfly'' plate in the air intake.
However, the convenient measurement of throttle plate position, has
no literal meaning for many engines other than conventional gasoline
engines. For a modern diesel engine, the hydraulically actuated,
electrically controlled unit injection (HEUI) fuel injectors function
as multiple throttles, and for a vehicle powered by an electric motor,
the motor speed controller is considered the throttle. For HEUI fuel
injectors and for electric motor speed controllers, there is no
observable component equivalent to a throttle that changes position
when the accelerator control is operated.
Furthermore, electronic accelerator control systems now being
installed on some gasoline engines have a spring-centered throttle
plate. In the absence of an electrical signal at the throttle plate
actuator, the spring-centered throttle opens much more than the usual
idle position. In the event the electronic accelerator control is
disconnected from the throttle plate actuator, these engines cannot
satisfy the present fail-safe criterion that the ``throttle return to
the idle position.'' On the other hand, engines of this design can
accomplish the essential fail-safe performance of returning engine
power to a satisfactory idle condition through spark timing control or
other means. However, strategies other than throttle plate return would
not be recognized as being in compliance under the present Standard.
For these reasons, we propose alternative performance criteria to
recognize the various ways in which a return to idle state power can be
achieved.
[[Page 48121]]
D. Criteria for Return to Idle in Normal Operation
Like the present Standard, the proposed Standard has return-to-idle
time requirements for two operating conditions: (1) Normal operation of
intact accelerator control systems, and (2) fail-safe operation in the
event of a severance or disconnection in the accelerator control
system. Regarding normal operation, the proposed Standard has retained
return of the air throttle to the idle position as the criterion for
air-throttled (gasoline) engines. The criterion is still valid for
normal operation of engines with mechanical accelerator controls and
also for air-throttled engines with electronic accelerator controls.
1. Diesel Engines--For diesels (and other fuel-throttled engines),
this proposal accepts TMA's suggestion that the return of the fuel
delivery rate (gallons/minute of fuel entering the combustion chambers
of the engine) to the idle state be used as the return to idle
criterion. For these engines, power is controlled directly by
controlling the fuel flow. The result of rapidly returning the
accelerator control to idle is a rapid return of the fuel rate to the
steady idle rate without the lag required to see the effect on engine
speed. In this respect, the fuel rate of fuel-throttled engines is much
like the throttle position of air-throttled engines.
2. HEUI Injectors With Multiple ``Throttles''--An engine with a
HEUI injection system, now commonplace in commercial trucks, is
potentially problematic with respect to return to idle criteria because
it has multiple ``throttles,'' its individual HEUI injectors, which can
operate independently of each other. This difficulty is overcome by
using a measured fuel rate that combines the action of the individual
injectors and represents the steady effect of all the injectors'
dynamic duty cycles (percent open time or pulse width and frequency).
It also solves the problem of the lack of a throttle reference position
and thus provides a satisfactory return-to-idle indicant. For many
trucks, a fuel rate signal that computes the combined effect of fuel
pressure and fuel injector duty cycles is available as a diagnostic
signal at the ECM. For engines without a reliable diagnostic signal,
direct measurement of fuel flow in the supply and return lines would be
necessary.
3. Electric Motors--For vehicles powered by electric motors, the
electric power input at the drive motor (computed from voltage and
current) can be used as the indicant of return-to-idle. This
measurement represents the operation of the motor speed controller
that, like an electronic fuel injector, is a throttle without a
measurable reference position. Since propulsive power is directly
proportional to the drive motor input current and voltage, this
indicant is equivalent to throttle position.
4. Response Time Requirements Will Be Retained--AAMA suggested
eliminating the response time requirements for return to idle in normal
operation, but the agency has chosen to retain these requirements. The
elimination of the requirements for normal operation was the subject of
a prior NPRM (see 61 FR 19020; April 30, 1996) (No DOT Docket No.)
which was withdrawn (see 62 FR 10514; March 7, 1997) (No DOT Docket
No.). These requirements continue to protect against accelerator
controls with poor operation due to mechanical friction.
E. Fail-Safe Performance Criteria
In the case of fail-safe operation, electronic accelerator control
systems can have a variety of ways of curtailing vehicle power in
response to an accelerator control system failure. Our intent in the
proposed Standard is to take advantage of those possibilities by
establishing fail-safe criteria that are performance-oriented rather
than design-oriented.
AAMA suggested a criterion for fail-safe behavior in the event of a
disconnection or severance of the accelerator control system that is
strictly performance based and applies to all forms of vehicle
propulsion. That criterion was that the maximum time to return to the
idle state in the presence of a single severance, disconnection, or
short circuit not exceed the time to return to the idle state in the
absence of any such fault by more than three seconds. AAMA further
suggested that the engine RPM would be used as the idle state indicant
for this test.
This suggested criterion appears to be simple and easily attainable
because of the extra three seconds of reaction time, but it is actually
a rigorous requirement and a difficult test to perform. We propose not
to restrict the test to operation in neutral, as initially suggested by
AAMA, because that restriction would neglect real driving safety. We
propose that in order to adequately determine whether propulsive power
is returned to the idle state, the appropriate time to be measured is
the time for a whole vehicle to slow from any speed and power condition
back to the speed at which the engine is at the idle RPM. It could
easily take 60 seconds for a vehicle to slow from 70 mph to an idle
speed of perhaps 20 mph as a result of simply lifting the driver's foot
from the accelerator pedal. Random differences in the effect of wind
and road surface alone make it unlikely that successive runs, even with
a vehicle free of faults, would be repeatable within 3 seconds unless
performed on an indoor dynamometer. Also, much of the deceleration is
the result of engine braking (negative driving torque), and it is
arguable that the safety purpose of the standard is satisfied by the
cessation of driving torque alone as a fail-safe response.
In the proposed rule, we have included AAMA's suggested RPM test as
performed on a dynamometer, in S6.4, as a compliance test of fail-safe
performance, and have made it valid for any type of engine or motor.
With the RPM test, the proposed standard includes a compliance test
that is purely performance-based and independent of design. However,
the RPM test is not the sole fail-safe test in the proposed standard
because of the disadvantages just described. This is because there are
several optional tests in addition to the RPM option for demonstrating
fail-safe performance that, though their applicability depends on
design, will be simpler and less burdensome to perform than the RPM
test for most vehicles.
1. Alternative Fail-Safe Performance Tests for Air-Throttled
Engines--For air-throttled engines, we propose three alternative tests.
The first test is the return of the throttle plate to the idle
position. This alternative is identical to the present standard and is
the least burdensome test for many vehicles in current production. The
second test alternative for air-throttled engines is return of the fuel
rate to the idle state. For engines of this type, engine power cannot
vary substantially from the idle state if the fuel rate is constrained
to the value observed at the idle state. Thus, fuel rate is a reliable
indicant that engine power is under control. The third test, the RPM
test, can be used if neither of the other two tests is compatible with
the vehicle's fail-safe design.
2. Alternative Fail-Safe Performance Tests for Fuel-Throttled
Engines--Since fuel-throttled engines such as diesel engines may
operate with excess air in the combustion chambers, neither the
position of an air throttle, if one is present, nor the air intake rate
would be an accurate indicant of engine power. Fuel rate, on the other
hand, is an accurate and sufficient indicant of engine power for these
engines. Consequently, we have included the same fuel rate criterion
specified for normal operation of fuel-throttled engines as an optional
test for fail-safe
[[Page 48122]]
performance of those engines. This test was suggested by TMA for both
normal and fail-safe operation. As stated above, the RPM test is the
other option for these types of engines.
3. Alternative Fail-Safe Performance Tests for Electric Vehicles--
For vehicles driven by electric motors, we are proposing that the
normal operation criterion for measuring throttle return time of
vehicles driven by electric motors, i.e., return of the drive motor
electric power input to the idle state, be used as an optional test of
fail-safe performance for these vehicles. Again, as stated above, the
RPM test is the other option for these vehicles.
4. Alternative Fail-Safe Performance Tests for Hybrid Vehicles--For
a hybrid vehicle with more than one type of propulsion system, the RPM
test could be applied to the various propulsion systems working
together. Alternatively, the fail-safe performance of the accelerator
controls of each separate propulsion system could be demonstrated
independently using either optional tests appropriate for each
propulsion system or the RPM test.
F. Irrevocable Selection of Test to Which Vehicle is Certified
While we propose alternative compliance options in order to
minimize the burden on manufacturers, we are also proposing to require
manufacturers to declare the option to which their compliance is
certified before the agency performs any compliance test of its own. We
have noted previously that when a safety standard provides
manufacturers with more than one compliance option, the agency needs to
know which option has been selected in order to conduct a compliance
test.
We have had previous experience with enforcing standards having
compliance options without an irrevocable election provision. A
manufacturer may certify a vehicle based on one compliance option but
subsequently, when confronted with an apparent noncompliance (based on
a compliance test) consistent with that choice, argue that the
compliance test is irrelevant because the vehicle complies with a
different compliance option. Such a shift in the manufacturer's
compliance stance would create obvious difficulties for the agency in
managing its available resources for carrying out its enforcement
responsibilities. By granting manufacturers the flexibility of
compliance alternatives, the agency does not intend to impose upon
itself an obligation to test each vehicle with each compliance option
to determine whether the vehicle in fact complies with this standard.
To avoid this circumstance, we intend to compel manufacturers to
inform the agency, when asked to do so, of the compliance option on
which its certification is based. The agency will test the vehicle in
accordance with that information and further will consider that choice
irrevocable. We will consider that test to be prima facie proof of
compliance or noncompliance, without regard to whether the vehicle may
comply with another option the manufacturer was not intending to rely
on. Further, we believe that a post hoc argument that a different
option can apply raises serious questions about the manufacturer's
compliance with its obligations under 49 U.S.C. 30115 to ensure, using
reasonable care, that its certificate is neither false nor misleading.
G. Definition of ``Idle State''
TMA and AAMA advised the agency in their comments that the idle
state is not fixed but varies according to a number of factors such as
engine temperature, accessory load, and emission controls. It may not
be possible for a manufacturer to specify absolute values for operating
characteristics of the idle state like throttle opening, engine speed,
and fuel rate because those characteristics can change according to
conditions, e.g., if the engine is warming up or the vehicle's air
conditioning is turned on. As a result, the idle state can vary over a
limited range without any input from the accelerator pedal. The idle
state also can be modified by speed setting devices such as cruise
control. Further, some engines may now employ a ``limp home'' mode
which can adjust engine operation to prevent stalling in the event of a
malfunction and to provide enough power for a vehicle to be moved from
an unsafe location.
For mechanical accelerator control systems, the current standard
accommodates the existence of a range of idle states by allowing any
idle position ``appropriate for existing conditions.'' Thus, in a
traditional air-throttled engine in which the idle position is
determined by a mechanical throttle stop, the throttle stop itself can
change position as dictated by operating conditions. For example, it
may move to a position of increased throttle opening when the engine is
cold. For compliance testing, the throttle stop provides a convenient
reference position that makes determination of compliance a simple
matter.
In vehicles with electronic engine controls, there may be no
reference position like a throttle stop. Therefore, it is necessary to
establish a reference or baseline value for the idle state, whether it
is measured by throttle position, fuel rate, RPM, or electrical power
input. The standard could require that the manufacturer specify a value
for the baseline, but it would be burdensome to have to obtain idle
state data for each of the numerous possible combinations of operating
conditions for each vehicle used in compliance testing.
Instead, it is easier and more practical to establish a baseline
simply by measuring the initial value of the applicable idle state
indicant (throttle position, fuel rate, RPM, electrical power input,
etc.) at the beginning of a compliance test (i.e., immediately before
the fault is induced). The initial value is an appropriate baseline
because it accounts for whatever operating conditions exist. Further,
it is a convenient baseline because it is measured directly at the time
of the test, and does not depend on information provided by the vehicle
manufacturer.
Once the baseline is established, the value of the idle state
indicant at the end of the test should be expected to be the same as
the baseline value established at the start of the test. Compliance is
indicated by whether or not the idle state returns to the baseline
value within the elapsed time specified in S5.3.
However, this approach only works if operating conditions such as
engine temperature, ambient temperature, accessory load, etc., are
constant during a test because on many vehicles there is no idle
reference position that adjusts along with those conditions. On an
electronic engine, idle state adjustments due to changes in operating
conditions would likely take place in the internal circuitry of the
ECM. Consequently, a noncomplying increase in idle state might be
indistinguishable from a permissible one.
Because of this, the proposed standard specifies that operating
conditions must be held constant during the test procedures. In a
compliance test, the engine must be stabilized before the test and all
accessory controls held constant so that any conditions that affect
idle state do not change during the course of the test. In order to
eliminate variations in engine idle that are not controlled by the
driver, the engine will be operated long enough to release the cold
start mechanism as well as to stabilize the emissions controls. The
reference or baseline value is established by observing the value of
the idle state indicant for an engine with a normally functioning
accelerator control system. For normal operation, the idle
[[Page 48123]]
state following any input to the accelerator pedal is compared to
baseline value, and in fail-safe operation, the idle state following a
disconnection in the accelerator control system is compared to the
baseline value. Return to the baseline must occur within the specified
time span. With the engine operating in a steady state with all
accessory controls held constant, any difference in the ``before and
after'' idle states could not be attributed to a change in operating
conditions.
H. Handling Limp Home Strategies
Limp home strategies allow for a temporary increase in idle speed
to keep an engine from stalling as a result of certain malfunctions,
and enhance safety and convenience by preserving limited mobility to
get a partially disabled vehicle off the roadway. The test procedures
for fail-safe performance identify the baseline idle state as the idle
state for a vehicle without a fault in the accelerator control system
(although the test could be run with faults in other engine systems).
The test requirements do not allow the vehicle to comply if it is in a
higher idle state at the end of the test because there would be no real
fail-safe requirement. Whatever idle state resulted from a fault in the
accelerator control system could be claimed as a limp-home mode induced
by the fault. The question of compliance would be essentially rendered
moot (although an unsafe idle condition might be considered a vehicle
safety defect.)
Neither TMA nor AAMA discussed the possibility of manufacturers
creating a limp home strategy specifically for accelerator control
system faults such as disconnections and severances. However, the
agency considered a hybrid vehicle, the Toyota Prius, which was
designed with a ``limp-off-the-road'' mode for such faults. In this
case, a disconnection of the pedal position sensor causes the electric
traction motor to receive enough power to move the vehicle off the
road. To assure safety, the power is removed upon any activation of the
service brake.
We do not view this design as presenting a safety or compliance
testing problem. Under the proposed test procedures, fail-safe
performance tests would be conducted with the brake pedal (or brake
lamp switch) depressed by the minimum amount necessary to cancel the
limp-off-the-road idle state during introduction of accelerator control
disconnections. We are proposing to include paragraph S5.4 in the
Standard to permit limp-off-the-road idle states for accelerator
control system faults, but only if they are canceled by any use of the
service brake. We have chosen to refer to these as ``limp-off-the-
road'' modes because we believe that term is a more accurate
description of what their purpose should be, and also to distinguish
them from ``limp-home'' modes that are designed to function in response
to faults not involving the accelerator control system.
I. Severance and Disconnection
Under the proposed revised standard, electrical connections could
be tested for disconnection of a whole connector and for the severance
of each individual conductor in the wiring at the connector. Each
conductor could be either left open or shorted to ground. This
treatment is consistent with the prior agency legal interpretations of
the standard relating to single point disconnections and severances in
electronic accelerator control systems. (See NHTSA interpretation
letter of August 8, 1988 to Isuzu Motors America, Inc.)
In the test procedures of the proposed regulatory text, ``induce
fault'' refers to the act of disconnecting one component of the
accelerator control system, or severing a single conducting wire to a
component, or disconnecting or severing one mechanical linkage or
spring within the accelerator control system.
J. Two Sources of Energy for Returning Throttle to Idle
At present, Standard No. 124 at S5.1 states that there shall be at
least two sources of energy capable of returning the throttle to the
idle position within the specified time limits from any accelerator
position or speed, whenever the driver removes the opposing actuating
force. S5.1 also specifies that, whenever one source of energy fails,
the other shall fulfill the return-to-idle function.
In the past, springs have been the predominant sources of energy
for return to idle. That appears to still be the case for accelerator
pedal (treadle) assemblies of vehicles with electronic accelerator
controls. These assemblies usually incorporate redundant springs. Such
springs would be considered part of the accelerator control system
under the proposed standard. Fail-safe operation would be tested by
disconnecting a spring, just as it is tested in the existing standard.
Although having two or more springs on the treadle is an effective
countermeasure for instances where a spring disconnection occurs, it is
not a sufficient condition to ensure return of the throttle to the idle
state. Many vehicles now have electric motors, solenoids, or other
devices to control the actual throttle on the engine. Redundant springs
on the treadle could be rendered irrelevant if, e.g., the electrical
connector to the treadle were disconnected. Under this proposal, fail-
safe performance could be tested by disconnecting any single spring in
the accelerator pedal or any single spring anywhere else in the ACS.
We believe that all sources of energy connected to the accelerator
control system for throttle return, whether springs, solenoids,
electric actuators, or other devices, should be treated uniformly as
single components whose disconnection must not result in losing control
of engine power.
Because the standard requires return to idle regardless of whether
there are two sources of energy present, the current requirement may be
considered somewhat redundant. Also, it is evident that many
manufacturers will provide two or more springs on treadle assemblies
whether there is an explicit requirement for it. Nevertheless, since we
tentatively conclude that this requirement would continue to ensure
that disconnection of one spring would not cause a runaway engine, we
propose to retain it in Standard No. 124.
K. Stabilization of Engine Power and Idle State Tolerance
A significant concern in the regulation of ACS failures is that
after a fault occurs, the engine should return to a benign power state
very quickly, and should also stabilize at a benign condition. It would
be unsafe for engine power to return only temporarily to a safe idle
state and subsequently jump to a relatively high idle, even after a
significant delay.
It is evident from agency tests that an engine with a fault in the
ACS may return to or below the baseline idle state initially and within
the specified time, but may not stabilize at or below the baseline.
Rather, engine power can increase after the initial return to idle.
Also, it is reasonable to expect that the idle level attained after
fault introduction might be subject to fluctuation because current
engines or motors operating in a fault condition might not always be
able to achieve a smooth, uniform idle state. Engine operation might be
rough, with speed oscillations and/or an elevated idle speed. These are
not unexpected side effects when severances or disconnections occur,
particularly in modern engines with electronic controls that might be
capable of evoking a variety of control strategies to avoid stalling.
Such variations in idle conditions may occur independently of
[[Page 48124]]
any limp-off-the-road provisions built into the engine control system.
The current standard is silent regarding the need to remain at idle
after returning to the idle state when a fault occurs. With traditional
mechanical linkages, there was little or no reason to believe that an
engine's fail-safe response would change after the first few seconds.
The throttle's initial return to or below the idle position after fault
introduction was thought to be a sufficient measure of performance, and
there was no need to consider engine power behavior at any later
instant.
The current standard does not allow for return to any condition
that is above the idle state, even by a small amount. Further, it does
not give any consideration to whether an elevated idle condition is
benign or not. In the past, the prevalence of mechanical throttle
systems made such considerations unnecessary because a broken
accelerator control system generally was not capable of making
adjustments in order to compensate for disconnections or severances.
With electronic engine controls, the situation has changed. Engine
computers continuously monitor engine operation. When the computer
recognizes a problem, it can adjust engine operation. Such adjustments
may occur on a delayed basis. Thus, power output behavior of electronic
engines can change over a period of seconds after a fault occurs. Even
if an engine returns to a safe power level initially, there might be
fluctuations in engine idle parameters. These fluctuations could
periodically exceed the baseline idle state by a significant amount.
For example, in one agency test of a fuel-throttled diesel engine
in a school bus (GTL Test No. 3473), in which a fault was introduced in
the ACS by severing one of the wires between the accelerator pedal
position sensor and the engine control module, the fuel rate signal
returned very quickly (within 0.2 seconds) to an indicated rate
approximately the same as the fuel rate at idle before the wire was
severed. By itself, this result appeared to indicate that the vehicle's
ACS met a safe level of performance. However, within one second after
fault introduction, the fuel rate increased momentarily to a level
(approximately 1.2 gallons/hour) that was 2.4 times the baseline value
(approximately 0.5 gallons/hour). The indicated fuel rate stabilized at
exactly the baseline rate or less only after about 3.4 seconds had
elapsed after fault introduction.
In this example, the initial return of indicated fuel rate to zero
was evidence that engine power had dropped to a safe level in response
to the ACS fault. Since the fuel rate subsequently increased before two
seconds had elapsed to a level greater than the baseline, it was
necessary to look at the fuel rate behavior for a greater time interval
after the fault was introduced to determine if the engine continued to
operate at a safe power level. In this case, it did so after a few
seconds.
We believe there is no safety reason why the engine power should
not be allowed to vary as long as a relatively benign idle condition is
achieved within the time specified in S5.3 of the existing standard and
maintained. In this example, the engine did return to a benign power
level, approximately equal to the baseline power level at idle, within
the prescribed time and it also did stabilize, after several seconds,
at exactly the baseline level.
In order to address issues relating to stabilization of the idle
state, we believe it is appropriate to require return to an idle state
that is reasonably close to the baseline idle state, even if not
identical to it, by specifying a tolerance which, when applied to the
baseline, defines a maximum safe idle condition while also providing
for some reasonable amount of variation.
We are proposing to permit a 50 percent increase from the idle
state in fail-safe operation. That is, the idle state achieved after
fault introduction must not be any more than 50 percent greater than
the baseline idle state as determined prior to fault introduction. This
level of tolerance would accommodate the kind of engine behavior such
as speed fluctuations that the agency observed in tests that were
conducted for the purpose of updating Standard No. 124. It would also
eliminate the need to either lengthen the allowable time to return to
idle in S5.3 or to specify an allowable delay before a complete return
to the baseline idle state is achieved in a compliance test.
We are also proposing to require that an engine must remain at the
idle state, within the 50 percent tolerance, after initially returning
to or below that level following a disconnection or severance. That is,
an engine or motor cannot be considered to comply if it returns to an
acceptable idle state only temporarily and then increases to a
relatively high power level. Under this proposal, the engine would be
required to remain at the idle state indefinitely. This requirement
would also prevent random or periodic fluctuations in idle state that
are large enough to significantly exceed the baseline idle state, even
though the idle state might be within compliance during portions of the
oscillations. We do not believe this requirement expands Standard No.
124's scope because we believe that a requirement to remain at idle
fulfills exactly the same safety need as the requirement to initially
return to idle, and it is, in fact, implied in the existing standard.
To measure fuel rate, engine RPM, or electric power, the 50 percent
tolerance would be calculated by multiplying the baseline value of the
measured quantity by 1.5. To measure the air throttle position, the
percent opening is the ratio of throttle plate angular displacement to
its full travel. It is calculated by dividing the angular displacement
to its full travel. The percent opening would be calculated by dividing
the angular displacement of the throttle plate relative to its fully
closed position by the angular displacement of the wide open throttle
relative to fully closed.
The above described definition of ``percent throttle opening'' is
included in the ``Definitions'' section of the proposed Standard. As an
example, a throttle plate that is designed to rotate 80 degrees from
its fully closed position to its fully open position would be
considered 20 percent open when rotated 16 degrees from its fully
closed position. If a baseline idle position for this throttle at given
idle state conditions were measured to be 8 degrees from the fully
closed position, then the 50 percent tolerance would be 4 degrees.
Thus, the maximum opening following fault inducement in S6.3.4 and the
release of the throttle in S6.3.5 would be 12 degrees from the fully
closed position.
VII. Leadtime
We propose that the new standard apply to passenger cars,
multipurpose passenger vehicles, trucks and buses manufactured on or
after the first September 1st that occurs two or more years after the
publication of the final rule. Public comment is sought on this
proposed lead time. We believe that two years is sufficient lead time
for industry since we do not believe that compliance with this proposed
rule would involve any new technology, or performance specifications
that manufacturers cannot meet with existing design, tooling, or
manufacturing capabilities. We further believe that conducting the
proposed test procedures would not involve any new technologies or
procedures that manufacturers would find difficult to conduct. Since
this rulemaking would not make any substantive changes in the scope of
Standard No. 124, manufacturers or passenger cars, multipurpose
passenger vehicles, trucks or buses would not need to make any changes
in vehicle manufacturing
[[Page 48125]]
processes or procedures to ensure that their vehicles meet Standard No.
124.
VIII. Regulatory Analyses and Notices
A. Executive Order 12866 and DOT Regulatory Policies and Procedures
Executive Order 12866, ``Regulatory Planning and Review'' (58 FR
51735, October 4, 1993), provides for making determinations whether a
regulatory action is ``significant'' and therefore subject to 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;
(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 rulemaking action under
Executive Order 12866 and the Department of Transportation's regulatory
policies and procedures. This rulemaking document was not reviewed by
the Office of Management and Budget under E.O. 12866, ``Regulatory
Planning and Review.'' The rulemaking action is also not considered to
be significant under the Department's Regulatory Policies and
Procedures (44 FR 11034; February 26, 1979).
The purpose of the proposed revision of Standard No. 124,
Accelerator control systems, is to specifically clarify the
requirements as they apply to ``non-mechanical'' accelerator control
systems, and not an expansion of the present requirements. These
proposed requirements were developed with the agency working in concert
with the motor vehicle industry, to prevent interpretation problems
that have been associated with the present standard. Therefore, there
are no new costs involved with the proposed revisions, and a regulatory
evaluation has not been prepared.
B. Executive Order 13132 (Federalism)
Executive Order 13132 requires us to develop an accountable process
to ensure ``meaningful and timely input by State and local officials in
the development of regulatory policies that have federalism
implications.'' ``Policies that have federalism implications'' is
defined in the Executive Order to include regulations that have
``substantial direct effects on the States, on the relationship between
the national government and the States, or on the distribution of power
and responsibilities among the various levels of government.'' Under
Executive Order 13132, we may not issue a regulation with Federalism
implications, that imposes substantial direct compliance costs, and
that is not required by statute, unless the Federal government provides
the funds necessary to pay the direct compliance costs incurred by
State and local governments, or unless we consult with State and local
governments, or unless we consult with State and local officials early
in the process of developing the proposed regulation. We also may not
issue a regulation with Federalism implications and that preempts State
law unless we consult with State and local officials early in the
process of developing the proposed regulation.
This proposed rule would not have substantial direct effects on the
States, on the relationship between the national government and the
States, or on the distribution of power and responsibilities among the
various levels of government, as specified in Executive Order 13132.
The reason is that this proposed rule, if made final, would apply to
motor vehicle manufacturers, and not to the States or local
governments. Thus, the requirements of Section 6 of the Executive Order
do not apply to this proposed rule.
C. Executive Order 13045 (Economically Significant Rules
Disproportionately Affecting Children)
Executive Order 13045 (62 FR 19885, April 23, 1997) applies to any
rule that: (1) Is determined to be ``economically significant'' as
defined under E.O. 12866, and (2) concerns an environmental, health or
safety risk that NHTSA has reason to believe may have a
disproportionate effect on children. If the regulatory action meets
both criteria, we must evaluate the environmental health or safety
effects of the planned rule on children, and explain why the planned
regulation is preferable to other potentially effective and reasonably
feasible alternatives considered by us.
This proposed rule is not subject to the Executive Order because it
is not economically significant as defined in E.O. 12866 and does not
involve decisions based on environmental, health or safety risks that
disproportionately affect children.
D. Executive Order 12778 (Civil Justice Reform)
Pursuant to Executive Order 12778, ``Civil Justice Reform,'' we
have considered whether this proposed rule would have any retroactive
effect. We conclude that it would not have such an effect. Under 49
U.S.C. 30103, whenever a Federal motor vehicle safety standard is in
effect, a State may not adopt or maintain a safety standard applicable
to the same aspect of performance which is not identical to the Federal
standard, except to the extent that the state requirement imposes a
higher level of performance and applies only to vehicles procured for
the State's use. 49 U.S.C. 30161 sets forth a procedure for judicial
review of final rules establishing, amending or revoking Federal motor
vehicle safety standards. That section does not require submission of a
petition for reconsideration or other administrative proceedings before
parties may file suit in court.
E. Regulatory Flexibility Act
Pursuant to the Regulatory Flexibility Act (5 U.S.C. 601 et seq.,
as amended by the Small Business Regulatory Enforcement Fairness Act
(SBREFA) of 1996) whenever an agency is required to publish a notice of
rulemaking for any proposed or final rule, it must prepare and make
available for public comment a regulatory flexibility analysis that
describes the effect of the rule on small entities (i.e., small
businesses, small organizations, and small governmental jurisdictions).
However, no regulatory flexibility analysis is required if the head of
an agency certifies the rule would 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 would not
have a significant economic impact on a substantial number of small
entities.
The Head of the Agency has considered the effects of this
rulemaking action under the Regulatory Flexibility Act (5 U.S.C. 601 et
seq.) and certifies that this proposal would not have a significant
economic impact on a substantial number of small entities. The
statement of the factual basis for the certification is that since this
rulemaking would not make any substantive changes in the scope of
Standard No. 124, small manufacturers of passenger cars, multipurpose
[[Page 48126]]
passenger vehicles, trucks or buses would not need to make any changes
in vehicle manufacturing processes or procedures to ensure that their
vehicles meet Standard No. 124. Accordingly, the agency believes that
this proposal would not affect the costs of motor vehicle manufacturers
considered to be small business entities.
F. National Environmental Policy Act
We have analyzed this proposal for the purposes of the National
Environmental Policy Act and determined that it would not have any
significant impact on the quality of the human environment.
G. Paperwork Reduction Act
NHTSA has determined that, if made final, this proposed rule would
not impose any ``collection of information'' burdens on the public,
within the meaning of the Paperwork Reduction Act of 1995 (PRA). This
rulemaking action would not impose any filing or recordkeeping
requirements on any manufacturer or any other party. For this reason,
we discuss neither electronic filing and recordkeeping nor do we
discuss a fully electronic reporting option by October 2003.
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 us to use voluntary consensus standards in our 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 us to provide Congress, through OMB,
explanations when we decide not to use available and applicable
voluntary consensus standards.
After conducting a search of available sources (including data from
International Organization of Standards or other standards bodies), we
have determined that there are not any available and applicable
voluntary consensus standards that we can use in this notice of
proposed rulemaking. We have searched the SAE's Recommended Practices
applicable to accelerator control systems. We found SAE J1843
Accelerator Pedal Position Sensor for Use with Electronic Controls in
Medium and Heavy-Duty Vehicle Applications APR93, the purpose of which
is to ``provide a common electrical and mechanical interface
specification that can be used to design electronic accelerator pedal
position sensors and electronic control systems for use in medium and
heavy-duty vehicle applications.'' However, the specifications in this
SAE Standard are limited to the pedal position sensor and a connector-
pin diagnostic. It does not provide guidance on the entire accelerator
control system. Since the SAE Standard does not provide guidance on an
issue material to this rulemaking, we have developed our own proposal.
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). Before promulgating a NHTSA rule for which a written
statement is needed, section 205 of the UMRA generally requires us 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 us 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 costs of $100 million or more to
either State, local, or tribal governments, in the aggregate, or to the
private sector. Thus, this proposal is not subject to the requirements
of sections 202 and 205 of the UMRA.
J. Data Quality Guidelines
After reviewing the provisions of this NPRM pursuant to OMB's
Guidelines for Ensuring and Maximizing the Quality, Objectivity,
Utility, and Integrity of Information Disseminated by Federal Agencies
(``Guidelines'') issued by the Office of Management and Budget (OMB)
(67 FR 8452, Feb. 22, 2002) and prepared, in draft form, by the
Department of Transportation (DOT) (67 FR 21319, Apr. 30, 2002), NHTSA
has determined that if made final, nothing in this rule would result in
``information dissemination'' to the public, as that term is defined in
the Guidelines.
If a determination were made that public distribution of data
resulting from this rule, constituted information dissemination and
was, therefore, subject to the OMB/DOT Guidelines, then the agency
would review the information prior to dissemination to ascertain its
utility, objectivity, and integrity (collectively, ``quality''). Under
the Guidelines, any ``affected person'' who believed that the
information ultimately disseminated by NHTSA was of insufficient
quality could file a complaint with the agency. The agency would review
the disputed information, make an initial determination of whether it
agreed with the complainant, and notify the complainant of its initial
determination. Once notified of the initial determination, the affected
person could file an appeal with the agency.
K. Plain Language
Executive Order 12866 requires each agency to write all rules in
plain language. Application of the principles of plain language
includes consideration of the following questions:
--Have we organized the material to suit the public's needs?
--Are the requirements in the rule clearly stated?
--Does the rule contain technical language or jargon that is not clear?
--Would a different format (grouping and order of sections, use of
headings, paragraphing) make the rule easier to understand?
--Would more (but shorter) sections be better?
--Could we improve clarity by adding tables, lists, or diagrams?
--What else could we do to make this rulemaking easier to understand?
If you have any responses to these questions, please include them
in your comments on this NPRM.
L. 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.
[[Page 48127]]
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 website at Click on ``Help &
Information'' or ``Help/Info'' to obtain instructions for filing the
document electronically.
How Can I be Sure That My Comments Were Received?
If you wish Docket Management to notify you upon its receipt of
your comments, enclose a self-addressed, stamped postcard in the
envelope containing your comments. Upon receiving your comments, Docket
Management will return the postcard by mail.
How do I Submit Confidential Business Information?
If you wish to submit any information under a claim of
confidentiality, you should submit three copies of your complete
submission, including the information you claim to be confidential
business information, to the Chief Counsel, NHTSA, at the address given
above under FOR FURTHER INFORMATION CONTACT. In addition, you should
submit two copies, from which you have deleted the claimed confidential
business information, to Docket Management at the address given above
under ADDRESSES. When you send a comment containing information claimed
to be confidential business information, you should include a cover
letter setting forth the information specified in our confidential
business information regulation. (49 CFR Part 512.)
Will the Agency Consider Late Comments?
We will consider all comments that Docket Management receives
before the close of business on the comment closing date indicated
above under DATES. To the extent possible, we 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 see the 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.''
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.
List of Subjects in 49 CFR Part 571
Imports, Motor vehicle safety, Motor vehicles, Rubber and rubber
products, Tires.
In consideration of the foregoing, it is proposed that the Federal
Motor Vehicle Safety Standards (49 CFR Part 571), be amended as set
forth below.
PART 571--FEDERAL MOTOR VEHICLE SAFETY STANDARDS
1. The authority citation for part 571 would continue 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 571.124 would be revised to read as follows:
Sec. 571.124 Standard No. 124; Accelerator control systems.
S1. Scope. This standard establishes requirements for the return of
engines and electric motors that are connected to a vehicle's drive
wheels to the idle state, whenever the actuating force on the driver-
operated accelerator control is removed, or there is a severance or
disconnection in the accelerator control system.
S2. Purpose. The purpose of this standard is to reduce deaths and
injuries resulting from engine over-speed caused by malfunctions in the
accelerator control system.
S3. Application. This standard applies to passenger cars, multi-
purpose passenger vehicles, trucks, and buses.
S4. Definitions.
Accelerator control system means all vehicle components, including
all engine control modules, that either operate the throttle in
response to movement of the driver-operated accelerator control or
return the driver-operated accelerator control and the throttle to the
idle position upon release of an actuating force.
Air throttle position means the ratio of the angular displacement
of the throttle plate in that position relative to its fully closed
position to its wide open angular displacement relative to its fully
closed position.
Air-throttled engine means an internal combustion engine in which
the power is regulated primarily through control of the air intake to
the combustion chambers.
Ambient temperature means the surrounding air temperature, at a
distance such that it is not significantly affected by heat from the
vehicle under test.
Driver-operated accelerator control means any device, such as the
accelerator pedal, that allows the driver to change the speed of a
vehicle's engine or motor by changing input to the device, but does not
include the cruise control or engine controls for other driver-operated
ancillary components or systems.
Fuel delivery rate means the rate at which fuel enters the
combustion chambers of an engine.
Fuel-throttled engine means an internal combustion engine in which
the power is regulated primarily through control of fuel delivery to
the combustion chambers.
Idle state means the engine power output to the drive wheels under
idle
[[Page 48128]]
state conditions when there is no input to the driver-operated
accelerator control.
Idle state conditions include, but are not limited to, engine
temperature, air conditioning load, emission control, limp home mode,
and the use of the cruise control.
Input electric power delivery means a power (wattage) computation
using the input current and voltage to an electric motor and an
appropriate power factor, if applicable.
Limp home mode means a device or design that restricts the engine
or motor to a limited speed range when certain faults other than
accelerator control system faults are detected by the engine management
system.
Limp-off-the-road mode means a device or design that increases
engine or motor speed above the idle state in response to a fault in
the accelerator control system.
RPM means the engine or motor speed in revolutions per minute.
Throttle means the component of an engine that is connected to the
accelerator control system and that controls the air intake to the
combustion chambers of an air-throttled engine, the fuel delivery to
the combustion chambers of a fuel-throttled engine or the electric
power to an electric traction motor in response to the driver-operated
accelerator control.
S5. Requirements. Each vehicle shall meet the following
requirements when its engine or motor is running under any load
condition, when tested under the applicable provisions of S6.
S5.1 Performance in Normal Operation. The throttle shall return to
or below the idle state within the time limit specified in S5.3 from
any position of the driver-operated accelerator control or any speed of
which the engine or motor is capable, whenever the actuating force is
removed from the driver-operated accelerator control. The idle state of
the throttle in normal operation is measured by one of the following
indicators when the engine or motor is at a stable idle and its idle
state conditions remain constant:
(a) the air throttle position of an air-throttled engine;
(b) the fuel rate to the combustion chambers of a fuel-throttled
engine; or
(c) the input electrical power (calculated from the measurements of
current and voltage) for an electric traction motor.
S5.2 Fail-safe Performance.
S5.2.1 In the event of disconnection or severance of any one
component of an accelerator control system at a single point, the
engine or motor power shall return to or below the idle state, within
the tolerance allowed by S6, within the time limit specified in S5.3,
from any position of the driver-operated accelerator control or any
speed of which the engine is capable. Each electronic control module in
an accelerator control system is considered to be a single component.
Severances and disconnections include those which can occur in the
external connections of an electronic control module to other
components of the accelerator control system and exclude those which
can occur internally in an electronic control module.
S5.2.2 The time to return to the idle state is measured either from
the first removal of the actuating force by the driver or from the time
of severance or disconnection.
S5.2.3 The accelerator control system shall meet the requirements
of this section when either open circuits or short circuits to ground
result from disconnections and severances of electrical wires and
connectors.
S5.2.4 Selection of compliance options. Where options for testing
fail-safe performance are specified in S6, the manufacturer shall
select the option by the time it certifies the vehicle and may not
thereafter select a different option for the vehicle. Each manufacturer
shall, upon request from the National Highway Traffic Safety
Administration, provide information regarding which of the compliance
options it has selected for a particular vehicle or make/model.
S5.3 Accelerator response time.
S5.3.1 Except as provided in S5.3.2, the maximum time to return to
idle state shall be 1 second for vehicles of 4,536 kilograms (10,000
pounds) or less gross vehicle weight rating (GVWR), and 2 seconds for
vehicles of more than 4,536 kilograms (10,000 pounds) GVWR.
S5.3.2 The maximum time to return to idle state shall be 3 seconds
for any vehicle that is exposed to ambient air at ``18 degrees Celsius
to ``40 degrees Celsius during a test or for any portion of the
conditioning period described in S6.
S5.4 Limp-Off-the-Road Mode for Accelerator Control System Faults.
S5.4.1 Any increase in the idle state as a limp-off-the-road mode
response to a fault in the accelerator control system that is greater
than the tolerances provided in S6. shall be removed upon application
of the service brake within the time limit specified in S5.3 and shall
not recur as long as the service brake is applied.
S5.4.2 For purposes of S5.4, application of the service brake means
any application that is sufficient to illuminate the vehicle's stop
lamps.
S5.5 Driver-Operated Accelerator Control. There shall be at least
two sources of energy, each of which is separately capable of returning
the driver-operated accelerator control to the idle position within the
applicable time limit specified in S5.3, from any position whenever the
driver removes the actuating force.
S6. Test Procedures and Conditions.
S6.1.1 The air-conditioning setting selected for testing shall be
any point within the vehicle's air conditioning control.
S6.1.2 If a vehicle is equipped with limp home mode, the idle state
condition is determined with the limp home mode either on or off.
S6.1.3 For idle state conditions such as emissions control that do
not provide a means of adjustment, the engine or motor will be operated
long enough to stabilize its idle state prior to testing.
S6.1.4 Air-throttled engines. An air-throttled engine is tested for
fail-safe performance under S6.2, S6.3, or S6.4, at the manufacturer's
option.
S6.1.5 Fuel-throttled engines. A fuel-throttled engine is tested
for fail-safe performance under S6.3, or S6.4 at the manufacturer's
option.
S6.1.6 Electric motors. An electric motor is tested for fail-safe
performance under S6.4 or S6.5 at the manufacturer's option.
S6.1.7 Baseline value. The baseline value is the value of the
engine or motor power indicant specific to each test procedure below
measured for an engine or motor without faults in its accelerator
control system for the idle state conditions that will exist at the
beginning and end of the test.
S6.1.8 Conditions applicable to all test procedures. The test
procedures are conducted with the vehicle's service brake applied by
the minimum amount necessary to disengage any limp-off-the-road mode
effects.
S6.1.9 Temperature. The conditioning and test procedures are
conducted at any ambient temperature between ``40 degrees Celsius and
+50 degrees Celsius.
S6.2 Return of Air Throttle Position.
S6.2.1 Condition the vehicle to the selected ambient temperature
for 12 hours.
S6.2.2 Operate the engine at idle long enough to determine the
baseline air throttle position for the idle state condition.
S6.2.3 Impose test load and engine speed conditions.
S6.2.4 Induce fault while measuring air throttle position.
S6.2.5 After at least 3 seconds, remove actuating force on driver-
operated accelerator control while measuring air throttle position.
[[Page 48129]]
S6.2.6 The air throttle shall return to and remain indefinitely in
a position that is no greater than 50 percent more open than the
baseline idle position of S6.1.2 in the response time specified in S5.3
following either S6.2.4 or S6.2.5.
S6.3 Return of Fuel Delivery Rate.
S6.3.1 Condition the vehicle to the selected ambient temperature
for 12 hours.
S6.3.2 Operate engine at idle long enough to determine fuel
delivery rate in the idle state.
S6.3.3 Impose test load and engine speed conditions.
S6.3.4 Induce fault while measuring fuel delivery rate.
S6.3.5 After at least 3 seconds, remove actuating force on driver-
operated accelerator control while measuring fuel delivery rate.
S6.3.6 The fuel delivery rate shall return to and shall remain
indefinitely at a value that is no greater than 50% more than the idle
state value of S6.3.2 in the response time specified in S5.3 following
either S6.3.4 or S6.3.5.
S6.4 Return of Engine or Motor RPM.
S6.4.1 This test is performed on a chassis dynamometer providing
the same resistance as a function of road speed for test runs as for
baseline runs.
S6.4.2 Vehicle load, tire pressures and all other factors affecting
rolling resistance are kept constant between baseline and test runs.
S6.4.3 Condition the vehicle to the selected ambient temperature.
S6.4.4 Operate the engine or motor at idle long enough to determine
the baseline idle RPM on the chassis dynamometer in the same gear which
will be selected for the baseline return-to-idle time measurement of
S6.4.5 and the fail-safe test of S6.4.8.
S6.4.5 Begin baseline return-to-idle time measurement by imposing
test load and engine or motor speed conditions.
S6.4.5.1 Return the external test load to that of S6.4.4 and
simultaneously remove the actuating force on the driver-operated
accelerator control.
S6.4.5.2 Record the time for the RPM to return to the idle RPM
determined in S6.4.4. plus 50 percent.
S6.4.6 Begin fail-safe test by imposing test load and engine or
motor speed conditions as in S6.4.5.
S6.4.7 Return the external test load to that of S6.4.4 and remove
the actuating force on the driver-operated accelerator control in the
manner of S6.4.6 and simultaneously induce fault while measuring RPM.
S6.4.8 The time following S6.4.9 for the RPM to return to a level
that is no greater than 50 percent more than the baseline idle RPM of
S6.4.4 shall not exceed the normal idle RPM return time of S6.4.7 by
more than three seconds.
S6.4.9 The RPM shall remain indefinitely at a level that is no
greater than 50 percent more than the baseline idle RPM of S6.4.4.
S6.5 Return of Input Power Delivery to an Electric Motor.
S6.5.1 Condition test vehicle to selected ambient temperature.
S6.5.2 Operate the motor at idle long enough to determine the
baseline idle input power (which may be zero for some vehicles.)
S6.5.3 Impose test load and engine speed conditions.
S6.5.4 Induce fault while measuring input voltage and total current
delivery.
S6.5.5 After at least 3 seconds, remove actuating force on driver-
operated accelerator control while measuring input voltage and total
current delivery.
S6.5.6 The input power to the motor shall return to and shall
remain indefinitely at a value that is no more than 50 percent greater
than the baseline idle value of S6.5.2 in the response time specified
in S5.3 following either S6.5.4 or S6.5.5.
Issued on: July 16, 2002.
Stephen R. Kratzke,
Associate Administrator for Safety Performance Standards.
[FR Doc. 02-18477 Filed 7-22-02; 8:45 am]
BILLING CODE 4910-59-Pb